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Pediatrics_Nelson. and atypical absence seizures. Although atonic seizures are typically brief (lasting 1 to 2 seconds), they are quite disabling because of a sudden loss of postural tone, resulting in falls and injuries.


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Pediatrics_Nelson. Seizures in the setting of fever may be caused by infections of the nervous system (meningitis, encephalitis, brainabscess), unrecognized epilepsy triggered by fever, or febrile seizures. The latter represents the most common cause ofseizures among children between 6 months and 6 years of age, occurring in about 4% of all children. By definition, a febrile seizure occurs in the presence of fever. Simple febrile seizures are generalized at onset, last less than 15 minutes, and occur only once in a 24-hour period in a neurologicallyand developmentally normal child. If there are focal features,the seizure lasts longer than 15 minutes or recurs within 24hours, or if the child has preexisting neurologic challenges,the seizure is referred to as a complex or atypical febrile seizure.


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Pediatrics_Nelson. The prognosis of children with simple febrile convulsionsis excellent. Intellectual achievements are normal. Febrile seizures recur in 30% to 50% of children. The risk of subsequentepilepsy is not substantially greater than that for the generalpopulation (approximately 2%). Factors that increase the riskfor the development of epilepsy include abnormal neurologicexamination or development, family history of epilepsy, andcomplex febrile seizures. Because febrile seizures are briefand the outcome is benign, most children require no treatment. Rectal diazepam can be administered during a seizureto abort a prolonged event and is a reasonable option forchildren with a history of prolonged febrile seizures. Becauseof the potential for side effects, daily administration of anticonvulsant medication is not recommended. Administration of antipyretics during febrile illnesses does not preventfebrile seizures.


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Pediatrics_Nelson. PNES (previously termed pseudoseizures) may be the manifestation of conversion disorders or malingering. Additionally, children with genuine epilepsy may, consciously or subconsciously, exhibit concurrent nonepileptic spells. Although the clinical differentiation can be difficult, PNES often differ from epileptic seizures in that the patient’s eyes are often closed (typically eyes are open during epileptic seizures) and the movement is tremulousness or thrashing rather than true tonic-clonic activity. Verbalization and pelvic thrusting are seen more commonly in PNES, urinary and fecal continence is usually preserved, and injury does not occur. If the tongue is bitten, more often the tip of the tongue is injured (as opposed to the sides of the tongue in epileptic seizures). PNES can often be initiated or terminated by suggestion. An EEG performed during PNES does not show epileptiform patterns. The diagnosis is critical, because appropriate mental health care, and not anticonvulsant


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Pediatrics_Nelson. be initiated or terminated by suggestion. An EEG performed during PNES does not show epileptiform patterns. The diagnosis is critical, because appropriate mental health care, and not anticonvulsant medications, is the crux of treatment.


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Pediatrics_Nelson. The epilepsy syndromes represent clinical entities in which age,pattern of clinical events, EEG features, natural history, andprognosis are distinctive (see Table 181-3).


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Pediatrics_Nelson. Benign childhood epilepsy with centrotemporal spikes, also known as benign Rolandic epilepsy, is among the most common epilepsy syndromes and usually begins between ages 5 and 10 years. The seizures typically occur only during sleep or on awakening in more than half of patients. Affected children usually have focal motor seizures involving the face and arm (abnormal movement or sensation around the face and mouth, drooling, rhythmic guttural sound). Speech and swallowing may be impaired. Seizures sometimes secondarily generalize. The interictal EEG demonstrates independent bilateral centrotemporal sharp waves but is otherwise normal. With a classic history and EEG, and a normal neurological examination, the diagnosis can be made with confidence and neuroimaging is not required. Seizures usually respond promptly to anticonvulsant therapy. Intellectual outcome is normal, and the epilepsy resolves after puberty. Comorbid learning difficulties and attention deficit/hyperactivity disorder


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Pediatrics_Nelson. respond promptly to anticonvulsant therapy. Intellectual outcome is normal, and the epilepsy resolves after puberty. Comorbid learning difficulties and attention deficit/hyperactivity disorder (ADHD) are common.


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Pediatrics_Nelson. Childhood absence epilepsy is another common syndrome. Absence seizures typically begin in the early school years and usually resolve by late childhood or adolescence. If absence does not remit, 44% will go on to develop juvenile myoclonic epilepsy (see later discussion). Ethosuximide is the first-choice therapy. A subset of patients also has generalized tonic-clonic seizures. For these children, valproic acid is the first choice as it can prevent both absence and convulsive seizures. Comorbid learning disabilities and ADHD are common. There is no contraindication to treating these children’s ADHD with stimulant medication.


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Pediatrics_Nelson. Juvenile myoclonic epilepsy (of Janz) is the most common generalized epilepsy among adolescents and young adults. Onset is typically in early adolescence with myoclonic jerks (exacerbated in the morning, often causing the patient to drop objects), generalized tonic-clonic seizures, and absence seizures. Seizures usually resolve promptly with anticonvulsant medication (classically valproic acid, but several medications have been shown to be efficacious), but therapy must be maintained for life.


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Pediatrics_Nelson. Infantile spasms are brief contractions of the neck, trunk, and arm muscles, followed by a phase of sustained muscle contraction lasting less than 2 seconds. Spasms occur most frequentlywhen the child is awakening from or going to sleep. Each jerkis followed by a brief period of relaxation with repeated spasmsin clusters of variable duration. Many clusters occur each day.West syndrome is the triad of infantile spasms, developmentalregression, and a dramatically abnormal EEG pattern (hypsarrhythmia). Hypsarrhythmia consists of chaotic high-voltageslow waves, spikes, and polyspikes. The peak age at onset is 3to 8 months. When flexion of the thighs and crying are prominent, the syndrome may be mistaken for colic or gastroesophageal reflux. The underlying etiology of the spasms dictates theprognosis. More than 200 different etiologies have been identified, including tuberous sclerosis, malformations of cortical development (lissencephaly), genetic syndromes (trisomy 21),acquired brain


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Pediatrics_Nelson. More than 200 different etiologies have been identified, including tuberous sclerosis, malformations of cortical development (lissencephaly), genetic syndromes (trisomy 21),acquired brain injury (stroke, perinatal hypoxic-ischemicencephalopathy), and metabolic disorders (phenylketonuria).Infants for whom an etiology is determined are classified as having symptomatic infantile spasms and are at very high risk for long-term neurodevelopmental difficulties. The etiology is notdetermined for a small subset of children. These patients withcryptogenic spasms have a somewhat better long-term prognosis but remain at high risk for adverse outcomes. First-line treatment options for infantile spasms include adrenocorticotropichormone, high-dose oral corticosteroids, and vigabatrin. Forinfants with underlying tuberous sclerosis, vigabatrin is considered the treatment of choice. For other patients, treatmentdeterminations are made on a case-by-case basis.


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Pediatrics_Nelson. Lennox-Gastaut syndrome is a severe epilepsy syndrome with variable age of onset. Most children present before age 5 years. Frequent, multiple seizure types, including atonic, focal, atypical absence, and generalized tonic, clonic, or tonic-clonic varieties, characterize the disorder. Many children have underlying brain injury or malformations. The seizures usually respond poorly to treatment, and most patients have significant intellectual disability. Benign neonatal convulsions are an autosomal dominant genetic disorder linked to abnormal neuronal potassium channels. Otherwise well newborns present with focal seizures toward the end of the first week of life, leading to the colloquial term fifth-day fits. Response to treatment is generally excellent, and the long-term outcome is typically favorable.


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Pediatrics_Nelson. Acquired epileptic aphasia (Landau-Kleffner syndrome)is characterized by the abrupt loss of previously acquired language in young children. The language disability is an acquired cortical auditory deficit (auditory agnosia). The EEG is highly epileptiform in sleep, the peak area of abnormality often being in the dominant perisylvian region (language areas). This diagnosis should be considered for young patients with clear autistic regression, as it is a potentially treatable entity.


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Pediatrics_Nelson. Status epilepticus is a neurologic emergency and is defined as ongoing seizure activity or repetitive seizures without return of consciousness for greater than 30 minutes. Status epilepticus carries an approximately 14% risk of new neurologic deficits, most secondary to the underlying pathology. Similarly, the mortality rate of status epilepticus (4% to 5%) is related to the underlying etiology. Etiologies include new-onset epilepsy of any type, drug intoxication, drug withdrawal (especially missed anticonvulsant doses among children with preexisting epilepsy), hypoglycemia, electrolyte imbalance, acute head trauma, infection, ischemic stroke, intracranial hemorrhage, metabolic disorders, and hypoxia.


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Pediatrics_Nelson. The first priority of treatment is to ensure an adequateairway, breathing, and circulation (Chapter 38). Vital signsshould be obtained and oxygen administered if needed.If respirations are inadequate, positive-pressure ventilation may be required. Intravenous (IV) access should beobtained. In patients with no history of seizures, laboratory evaluation should be undertaken (see below). Severalpharmacologic options exist for management of status epilepticus (Table 181-5). Initial management is usually witha benzodiazepine. Lorazepam, diazepam, and midazolamall are effective agents. Diazepam distributes rapidly to the brain but has a short duration of action. If IV access is not available, liquid preparations may be administered per rectum. If the seizure does not resolve after two dosesof benzodiazepine, a second-line agent must be administered. Either IV phenytoin or fosphenytoin is effective, butcardiac monitoring is required to evaluate for arrhythmia.If the seizures persist, a


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Pediatrics_Nelson. benzodiazepine, a second-line agent must be administered. Either IV phenytoin or fosphenytoin is effective, butcardiac monitoring is required to evaluate for arrhythmia.If the seizures persist, a loading dose of phenobarbital orvalproic acid is appropriate (see Table 181-5). Alternatively,continuous infusions, such as midazolam or pentobarbital,can be employed as third-line agents (with appropriate airway protection, blood pressure support, and strong consideration of continuous video-EEG monitoring to evaluate for ongoing subclinical seizures). If this approach is ineffective, preparations for general anesthesia are undertaken.When status epilepticus stops, maintenance therapy is initiated with the appropriate anticonvulsant.


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Pediatrics_Nelson. For an otherwise healthy child with an unprovoked seizure anda normal physical and neurological examination, no laboratoryevaluation is required. Children with simple febrile seizures who have recovered completely require little or no laboratory evaluation other than studies necessary to evaluate the sourceof the fever. If the clinical presentation does not meet thesecriteria and acute symptomatic seizures are suspected, potentially life-threatening causes such as meningitis, sepsis, headtrauma, and toxins should be pursued. A complete laboratoryevaluation for new onset of seizures includes a complete bloodcount and measurement of glucose, calcium, sodium, potassium, chloride, bicarbonate, urea nitrogen, creatinine, magnesium, and phosphorus, as well as blood or urine toxicology ABCs (airway, breathing, circulation) Basic metabolic panel—sodium, calcium, magnesium Toxicology studies as appropriate Complete blood counts, platelets, and differential


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Pediatrics_Nelson. Basic metabolic panel—sodium, calcium, magnesium Toxicology studies as appropriate Complete blood counts, platelets, and differential Benzodiazepine (max rate of administration = 1 mg/min) Lorazepam 0.05–0.1 mg/kg (maximum 2–4mg per dose) Diazepam 0.2–0.5 mg/kg Midazolam 0.1–0.2 mg/kg screening. Children with clinical signs and symptoms of meningitis (neck stiffness, Kernig sign, Brudzinski sign), or historyor physical examination suggestive of intracranial infection,should undergo a lumbar puncture. Cerebrospinal fluid (CSF)should be analyzed for cell counts, culture, protein, and glucose levels. In children less than 18 months old, particularlyyoung infants, the clinical symptoms of meningitis may besubtle. Neonates also may require testing for inborn errors ofmetabolism; blood ammonia; CSF glycine and lactate, as wellas herpes simplex polymerase chain reaction; urine and stoolculture (cytomegalovirus and enterovirus); and a clinical trial of pyridoxine.


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Pediatrics_Nelson. The EEG is the most useful neurodiagnostic test for distinguishing seizures from nonepileptic paroxysmal disorders and for classifying seizures as having focal or generalized onset. The EEG must be interpreted in the context of the clinical history, because some normal children have focal or epileptiform EEG patterns. Children with seizures may have normal interictal EEGs. When the diagnosis is unclear, more sophisticated EEGs with prolonged recordings and simultaneous video monitoring of the patient in an attempt to capture a typical event may be necessary.


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Pediatrics_Nelson. Magnetic resonance imaging (MRI) is superior to computed tomography (CT) in showing most brain pathology,but in the emergency department setting, CT can be performed rapidly and often shows acute intracranial hemorrhage more clearly than MRI. MRI is unnecessary inpatients with the primary generalized epilepsies, such astypical absence and juvenile myoclonic epilepsy. Lesions (tumors, arteriovenous malformations, cysts, strokes, gliosis, focal atrophy) may be identified in 25% of patients,even when the clinical examination and EEG do not suggest focal features. Identification of some lesions, such asfocal cortical dysplasia, hamartoma, and mesial temporalsclerosis, can assist in consideration of surgical treatmentof pharmacoresistant epilepsy.


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Pediatrics_Nelson. The decision to institute daily seizure medications for a firstunprovoked seizure is based on the likelihood of recurrencebalanced against the risk of long-term drug therapy. Determination of the recurrence risk is based on the clinical historyand neurodiagnostic testing (Table 181-6). If the recurrencerisk is 75% or greater, it is usually suggested that daily medication be prescribed. Absence seizures, infantile spasms,atypical absence seizures, and atonic seizures are universallyrecurrent at the time of diagnosis, indicating the need fortherapy. Table 181-6 Recurrence Risk after a First Unprovoked Seizure* SEIZURE TYPE EEG NORMAL, EXAM NORMAL EEG EPILEPTIFORM OR EXAM ABNORMAL BOTH EEG AND EXAM ABNORMAL Special circumstances: 1. For absence epilepsy, ethosuximide is the first line treatment. 2. Adrenocorticotropic hormone, oral corticosteroids, or vigabatrin are used to treat infantile spasms. Figure 181-1 Treatment for epilepsy.


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Pediatrics_Nelson. The goal of treatment is to maintain an optimal functional state. Medication toxicity should be weighed againstthe risk of seizure itself. Initial drug selection is based on themechanism of the seizure (Fig. 181-1). A single agent limitstoxicity, contains cost, and improves compliance. Approximately 60% of children obtain satisfactory seizure controland minimal side effects with the initial drug. If seizurecontrol is not achieved, despite good compliance, additionof a second drug is considered. When available, measuring anticonvulsant blood levels can be helpful in adjustingdosing and monitoring compliance. Levels should be interpreted in light of the patient’s clinical state; a patient with a “low” drug level who is seizure free does not necessarilyneed a higher dose. Anticonvulsant drug levels should bedrawn at trough, usually before the morning doses. When hepatic or renal disease is present, drug binding is likely tobe altered. In this instance, free and bound anticonvulsant


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Pediatrics_Nelson. drug levels should bedrawn at trough, usually before the morning doses. When hepatic or renal disease is present, drug binding is likely tobe altered. In this instance, free and bound anticonvulsant levels can be helpful.


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Pediatrics_Nelson. The duration of anticonvulsant treatment varies according to seizure type and epilepsy syndrome. For most children, anticonvulsant medications can be weaned off after 2 years without seizures. There are some exceptions. Forexample, children with juvenile myoclonic epilepsy, progressive myoclonic epilepsy, atypical absence seizures, and Lennox-Gastaut syndrome usually require treatment for life. Children who have other neurological comorbidities, seizures that were initially difficult to control, orpersistently epileptiform EEGs are at highest risk for recurrence when therapy is discontinued.


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Pediatrics_Nelson. Although cognitively normal children with epilepsy havethe same rates of injury as normal healthy children, thereare important safety considerations for people with epilepsy.The risk of drowning is high, so swimming and bathing mustonly occur under direct adult supervision. Children shoulduse appropriate helmets for sports such as bicycling or iceskating. There is no contraindication to participation in contact sports, but scuba diving, hang gliding, and free climbing are not safe for people with epilepsy. Each country andindividual states have specific laws regarding driving for people with epilepsy. Most require a period of seizure freedombefore issuing a driving permit.


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Pediatrics_Nelson. Weakness is a decreased ability to voluntarily and actively movemuscles. This may be generalized or localized to one aspectof the body. Hypotonia is a state of low muscle resistance to movement. Hypotonia can be associated with weakness, but insome cases is present with normal motor strength. The differential diagnosis for weakness is extensive (Table 182-1). Weakness and hypotonia may be due to disorders of upper motor neurons or lower motor neurons. Upper motor neurons originatein the cerebral motor cortex; their axons form the corticospinaltract ending in the spinal cord and control voluntary motor activity. The anterior horn cells, their motor roots, peripheral motornerves, neuromuscular junctions, and muscles represent the lower motor neurons and muscle units. Maintenance of normal strength, tone, and coordination requires integrated communication throughout this complex system, including the cerebral cortex,cerebellum, brainstem, thalamus, basal ganglia, and spinal cord.


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Pediatrics_Nelson. Available @ StudentConsult.com Weakness caused by upper motor neuron disease differs fromweakness produced by lower motor units (Table 182-2). Dysfunction of the upper motor neuron causes loss of voluntary Neuromuscular junction Myasthenia gravis (juvenile, transient neonatal, congenital) Botulism Muscle Muscular dystrophies (Duchenne, Becker, limb-girdle) Myotonic dystrophies Congenital myopathies Metabolic myopathies Dermatomyositis Polymyositis neuron, the final common pathway producing muscle activity, leads to total absence of movement with hypotonia. Function is best tested by measuring the strength of individual muscle groups or, in a young child, by observing the ability to perform tasks requiring particular muscle groups (e.g., walk up or down stairs, arise from the ground, walk on toes or heels, raise the hands above the head, squeeze a ball).


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Pediatrics_Nelson. Tumors, trauma, infections, demyelinating syndromes, infarction, metabolic diseases, and degenerative diseases may injure the corticospinal tract, producing an upper motor neuron pattern of weakness coupled with increased deep tendon reflexes, spasticity, and extensor plantar responses (Babinski sign). The distribution of weakness depends on the location of the lesion. A tumor in the left parietal region may produce a right hemiparesis. A brainstem glioma may produce a slowly progressive quadriparesis. A diffuse disorder of myelin synthesis, such as a leukodystrophy, would produce a progressive symmetrical quadriparesis. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Acute spinal cord lesions, such as infarction or compression, may produce a flaccid, areflexic paralysis that mimics lower motor neuron disease. A child who exhibits an acute or subacute flaccid paraparesis is most likely to have eitheran acute cord syndrome or Guillain-Barré syndrome. Thehallmarks of spinal cord disease are a sensory level, a motorlevel, disturbance of bowel and bladder function, and local spinal pain or tenderness. The acute cord syndrome maybe the result of transverse myelitis, cord tumor, infarction, demyelination, or trauma. Transverse myelitis, an acute postinfectious demyelinating disorder of the spinal cord, istreated with high-dose steroids. Trauma and tumors (neuroblastoma, lymphoma, sarcoma) compressing the spinalcord necessitate immediate neurosurgical management topreserve vital function.


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Pediatrics_Nelson. Neuromuscular disease affects any component of the lower motor neuron unit. The distribution of muscle weakness can point toward specific diseases (Table 182-3). Progressive degeneration of anterior horn cells is the key manifestation of spinal muscular atrophy (SMA), a genetic diseasethat may begin in intrauterine life or any time thereafter. About control, but not total loss of movement because motor nuclei of the basal ganglia, thalamus, and brainstem have tracts that produce simple or complex stereotyped patterns of movement. Thecorticospinal tract permits fine motor activity and is best testedby rapid alternating movements of the distal extremities. Milddysfunction produces slowed, stiff motions. More severe dysfunction produces stiff, abnormal involuntary postures (spasticity) consisting of forearm flexion at the elbow and wrist andadduction close to the chest, with leg extension and adduction.


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Pediatrics_Nelson. Damage to the spinal cord leaves residual simple, stereotyped reflex movements coordinated by local spinal reflexes below the level of the lesion. Destruction of the lower motor Brain tumor Trauma (accidental, nonaccidental) Infection (meningitis, encephalitis, abscess) Ischemia (arterial or venous) Hemorrhage Metabolic disease (leukodystrophy; inborn error of metabolism; mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) Degenerative disease Botulism Myotonic dystrophy Congenital myotubular myopathy Miller Fisher variant of Guillain-Barré Botulism Polio Miller Fisher variant of Guillain-Barré 25% of patients have a severe infantile form (SMA type1/Werdnig-Hoffmann disease), 50% have a late infantile and more slowly progressive form (SMA type 2/Kugelberg-Welander syndrome), and 25% have a more chronic,juvenile form (SMA type 3). SMA is one of the most frequentautosomal recessive diseases, with a carrier frequency of 1 in 50. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com The earlier in life the process starts, the more severe the progression. Infants with SMA type 1 present in early infancy with severe hypotonia, generalized weakness, and facial involvement. Infants have normal cognitive, social, and language skills and sensation. Fasciculations (quivering of the lateral aspect of the tongue) are best identified by inspecting the mouth when the child is asleep. Deep tendon reflexes are absent. With progression, breathing becomes rapid, shallow, and predominantly abdominal. In an extremely weak child, respiratory compromise leads to atelectasis, pulmonary infection, and death. Most infants with SMA type 1 die within the first 2 years. Children with SMA type 2 may survive to adulthood. Children with SMA type 3 can appear normal, with slower progression of weakness and a normal life expectancy.


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Pediatrics_Nelson. The diagnosis is made by genetic testing. Creatine phosphokinase (CK) may be normal or mildly elevated. The electromyelogram (EMG) shows fasciculations, fibrillations, and other signs of denervation. Muscle biopsy specimens show grouped atrophy. No specific treatment delays progression of SMA, although a number of promising agents are being studied. Symptomatic therapy is directed toward minimizing contractures, preventing scoliosis, maximizing nutrition, and avoiding infections. Respiratory infections are managed early and aggressively with pulmonary hygiene, oxygen, and antibiotics. The use or nonuse of artificial ventilation and tube feedings must be individualized for each patient in each stage of the illness.


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Pediatrics_Nelson. There are many peripheral nerve diseases in childhood, but the most classic presentations are: Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), hereditary motor sensory neuropathy (HMSN), and tick paralysis. Peripheral neuropathies produced by diabetes mellitus, alcoholism, chronic renal failure, exposure to toxins, vasculitis, and the effects of neoplasm are common in adults but are rare in children. Guillain-Barré syndrome (acute inflammatory demyelinating polyradiculoneuropathy) is a postinfectious autoimmune peripheral neuropathy that can occur about 10 days after a respiratory or gastrointestinal infection (classically Mycoplasma pneumonia or Campylobacter jejuni). It occurs in people of all ages and is the most common cause of acute flaccid paralysis in children.


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Pediatrics_Nelson. The characteristic symptoms are areflexia, flaccidity, and symmetrical ascending weakness. Progression can occur rapidly, in hours, or more indolently over weeks. Typically symptoms start with numbness or paresthesia in the hands and feet, then a heavy, weak feeling in the legs. Weakness ascends to involve the arms, trunk, and bulbar muscles (tongue, pharynx, larynx). Deep tendon reflexes are absent even when strength is relatively preserved. Objective signs of sensory loss are usually minor compared with the dramatic weakness. Bulbar and respiratory insufficiency may progress rapidly. Dysfunction of autonomic nerves can lead to blood pressure changes, tachycardia and other arrhythmias, urinary retention or incontinence, or stool retention. This polyneuropathy can be difficult to distinguish from an acute spinal cord syndrome. Preservation of bowel and bladder function, loss of arm reflexes, absence of a sensory level, and lack of spinal tenderness point toward Guillain-Barré


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Pediatrics_Nelson. distinguish from an acute spinal cord syndrome. Preservation of bowel and bladder function, loss of arm reflexes, absence of a sensory level, and lack of spinal tenderness point toward Guillain-Barré syndrome. A cranial nerve variant of Guillain-Barré syndrome called the Miller Fisher variant manifests with ataxia, partial ophthalmoplegia, and areflexia.


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Pediatrics_Nelson. The cerebrospinal fluid in Guillain-Barré syndrome is sometimes normal early in the illness but classically shows elevated protein levels without significant pleocytosis. Magnetic resonance imaging (MRI) with gadolinium may reveal enhancement of the spinal nerve roots. Electrophysiology studies (EMG, nerve conduction velocity [NCV]) are not always required but can provide corroborative diagnostic evidence and prognostic indicators.


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Pediatrics_Nelson. Children in early stages of the disease should be admitted to the hospital. Those with moderate, severe, or rapidly progressive weakness should be cared for in an intensive care unit. Pulmonary and cardiac functions are monitored continuously. Endotracheal intubation should be performed in patients with impending respiratory failure or an inability to clear secretions. Most patients are treated initially with intravenous immunoglobulin (IVIG). Plasma exchange and immunosuppressive drugs are alternatives when IVIG treatment is unsuccessful or in rapidly progressive disease. Physical, occupational, and speech therapies are mainstays of treatment. The illness usually resolves spontaneously, albeit slowly; 80% of patients recover normal function within 1 to 12 months. Twenty percent of patients are left with mild to moderate residual weakness. Some children will suffer acute relapse or chronic symptoms.


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Pediatrics_Nelson. CIDP is an immune-mediated peripheral neuropathy and canaffect patients of all ages. Patients present with both proximal and distal weakness (usually in an episodic, relapsing-remitting pattern) affecting the extremities. Patients may alsoexperience sensation changes such as numbness, tingling, or pain. The diagnosis is clinical, although EMG or nerve biopsymay confirm the diagnosis. The mainstays of treatment forCIDP are IVIG, glucocorticoids, and plasmapheresis. Prognosis varies, with some patients undergoing complete remission, whereas others experience partial remission or severedisability. HMSN (also called Charcot-Marie-Tooth Disease [CMT]) is a group of progressive peripheral nerve diseases. Motor components generally dominate the clinical picture, with sensation and autonomic functions affected later. The most common HMSN is CMT type 1A. Other forms may have milder symptoms. Some subtypes present with severe symptoms starting in infancy.


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Pediatrics_Nelson. The peroneal and tibial nerves are the earliest and most severely affected. Most often, complaints begin in the preschool to early adolescent years, with weakness of the ankles and frequent tripping. Examination shows pes cavus deformity of the feet (high-arched feet), bilateral weakness of foot dorsiflexors, and normal sensation despite occasional complaints of paresthesia. Peripheral nerves can become markedly enlarged and may be palpable on exam. Progression of HMSN is slow, extending over years and decades. Eventually, patients develop weakness and atrophy of the entire lower legs and hands and mild to moderate sensory loss in the hands and feet. Some patients never have more than a mild foot deformity, loss of ankle reflexes, and electrophysiologic abnormalities. Others in the same family may be confined to a wheelchair and have difficulties performing everyday tasks with their hands.


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Pediatrics_Nelson. HMSN can be either demyelinating (CMT1, with severelydecreased NCV and hypertrophic changes on sural nervebiopsy) or axonal (CMT2, with normal NCV but decreased action potential amplitudes and axonal degeneration onbiopsy). Specific genetic testing is available for many subtypes of HMSN. Specific treatment for HMSN is not available,but braces that maintain the feet in dorsiflexion can improvefunction. Available @ StudentConsult.com Tick paralysis produces an acute lower motor neuron pattern of weakness, clinically similar to Guillain-Barré syndrome. An attached female tick releases a toxin, similar to botulism, blocking neuromuscular transmission. Affected patients present with a severe generalized flaccid weakness, including ocular, papillary, and bulbar paralysis. A methodical search for an affixed tick, particularly in hairy areas, must be made in any child with acute weakness. Removal of the tick results in a prompt return of motor function. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Myasthenia gravis is an autoimmune condition. Most commonly, antibodies block the acetylcholine receptors (AChR) at the neuromuscular junction, decreasing the number of effective receptors, which results in rapid fatigability of striated muscle, though other types of auto-antibodies exist. The three childhood varieties are juvenile myasthenia gravis in late infancy and childhood, transient neonatal myasthenia, and congenital myasthenia.


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Pediatrics_Nelson. Variable ptosis, diplopia, ophthalmoplegia, and facial weakness are the presenting symptoms. Dysphagia, poor headcontrol, and extremity weakness may occur. Rapid fatigueof muscles distinguishes myasthenia from other neuromuscular disorders, with progressive worsening over theday or with repetitive activity. In some children, the disease never advances beyond ophthalmoplegia and ptosis (ocular myasthenia). Others have a progressive andpotentially life-threatening illness that involves all musculature, including that of respiration and swallowing.Treatment includes pyridostigmine, an inhibitor of acetylcholinesterase, and, depending on severity, various forms ofimmunosuppression.


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Pediatrics_Nelson. A transient myasthenic syndrome develops in 10% to 20% of neonates born to mothers with myasthenia gravis, presenting in the first hours to days after birth. Almost all infants born to mothers with myasthenia have maternal anti-AChR antibodies. Signs include ptosis, ophthalmoplegia, weak facial movements, poor feeding, hypotonia, respiratory difficulty, and variable extremity weakness. Neonates with transient myasthenia gravis require cholinesterase inhibitors and supportive care for a few days to weeks until the weakness remits.


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Pediatrics_Nelson. A variety of rare disorders of the neuromuscular junction have been reported that are not autoimmune mediated. The congenital myasthenic syndromes (CMS) are due to gene mutations in the components of the neuromuscular junction. They typically present in infancy with hypotonia, ophthalmoparesis, facial diplegia, and extremity weakness, although they can present throughout childhood. Respiratory function and feeding may be compromised. Children with CMS usually have lifelong disability. Some children will respond to pyridostigmine or other drugs that improve neuromuscular junction function.


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Pediatrics_Nelson. Autoimmune myasthenia is most commonly diagnosed through the combination of clinical symptoms and antibody testing. The majority of individuals have antibodies to the AChR, although some have antibodies to other components of the neuromuscular junction. Neurophysiology may exhibit the classic feature of electrodecrement with 3-Hz repetitive stimulation during nerve conduction studies. Administration of a cholinesterase inhibitor (edrophonium chloride) can result in transient improvement in strength, particularly of ptosis, and thus can additionally be used for diagnostic verification. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Infant botulism results from intestinal infection by Clostridium botulinum, which produces a neurotoxin that blocks presynaptic cholinergic transmission. Young age and the absence of competitive bowel flora predispose infants to this disease. Infants may ingest dust, soil, or food (honey or poorly canned foods) contaminated with spores. The progressive neuromuscular blockade ranges from mild to severe. Infants often present with constipation and poor feeding. Hypotonia and weakness develop, along with cranial nerve dysfunction manifested by decreased gag reflex, diminished eye movements, decreased pupillary contraction, and ptosis. Heart rate and blood pressure may fluctuate. Affected infants may develop respiratory failure. The diagnosis is made by the presence of C. botulinum spores and toxin in stool samples. Therapy with botulism IVIG should be administered as soon as the diagnosis is suspected.


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Pediatrics_Nelson. With prompt treatment and respiratory and supportive care, the prognosis is good. Muscular dystrophies are a group of genetic muscle diseases characterized by progressive myofiber degeneration and the gradual replacement of muscle by fibrotic tissue. Duchenne muscular dystrophy is the most common muscular dystrophy and one of the most common genetic disorders of childhood. Duchenne muscular dystrophy is an X-linked disorder (Xp21) affecting approximately 1 in 3500 boys and resulting from a gene mutation of dystrophin. Becker muscular dystrophy is an allelic disorder associated with more mild symptoms; its mutations at least partially preserve the function of the resulting gene product. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Infant boys are only rarely symptomatic in early infancy. At about 2 to 3 years of age, boys develop an awkward gait and an inability to run properly. Some have an antecedent history of mild slowness in attaining motor milestones or poor head control during infancy. Examination shows firm calf hypertrophy and mild to moderate proximal leg weakness with a hyperlordotic, waddling gait. The child typically arises from a lying position on the floor by using his arms to climb up his legs and body (Gower sign). Arm weakness is evident by age 6 years, and most boys are wheelchair dependent by age 12 years. Other manifestations include cardiomyopathy, scoliosis, respiratory decline, and, in some boys, cognitive and behavioral dysfunction. Many boys with Duchenne live into adulthood. Most die in their 20s or early 30s, usually as a result of progressive respiratory decline or cardiac dysfunction.


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Pediatrics_Nelson. Serum CK levels are always markedly elevated. Diagnosis is established by genetic testing for the dystrophin gene mutation. Prenatal diagnosis is possible. Approximately one third of cases represent new mutations. Occasionally, the diagnosis is not made until a muscle biopsy shows muscle fiber degeneration and regeneration accompanied by increased intrafascicular connective tissue. Steroid therapy is now instituted to slow the pace of the disease and delay motor disability. Supportive care includes physical therapy, bracing, proper wheelchairs, and treatment of cardiac dysfunction or pulmonary infections. A multidisciplinary approach is recommended. Through improvements in management, patients are now living significantly longer than in the pre-steroid era.


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Pediatrics_Nelson. Myotonic dystrophy (DM) is the second most common muscular dystrophy and the most common form to present in adulthood. An autosomal dominant genetic disease, DM is caused by progressive expansion of a triplet repeat, CTG, in the myotonic dystrophy protein kinase gene. Presentation is roughly correlated with the number of CTG repeats, and the disease is characterized by genetic anticipation, where each generation presents with earlier and more severe symptoms.


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Pediatrics_Nelson. Although DM most typically presents in adulthood, it can present at any age. Clinical features of childhood-onset “classic” DM include slowly progressive facial and distal extremity weakness as well as myotonia. Myotonia is a disorder of muscle relaxation after contraction. Patients grasp onto an object and have difficulty releasing their grasp, peeling their fingers away slowly. The facial appearance is characteristic, with hollowing of muscles around temples, jaw, and neck; ptosis; facial weakness; and drooping of the lower lip. The voice is nasal and mildly dysarthric. Not only is the striated muscle affected, but smooth muscle of the alimentary tract, uterus, and cardiac tissue are involved. Patients have variable arrhythmias, endocrinopathies, immunologic deficiencies, cataracts, and intellectual impairment.


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Pediatrics_Nelson. A severe congenital form of DM can appear in infants of mothers with myotonic dystrophy because of rapid expansion of the CTG repeat length. Infants are immobile and hypotonic, with ptosis, absence of sucking and Moro reflexes, poor feeding, and respiratory difficulties. Often, weakness and atony of uterine smooth muscle during labor lead to associated hypoxic ischemic encephalopathy and its sequelae, which make the clinical diagnosis more difficult. The presence of congenital contractures, clubfoot, or a history of poor fetal movements indicates intrauterine neuromuscular disease. Those requiring prolonged ventilation have an infant mortality of 25%. Individuals with congenital DM often make significant gains in terms of motor skills, and nearly all children eventually ambulate independently. However, approximately 50% of DM patients have mental retardation. In addition, children with congenital DM experience a second progressive phase of the disease in the teen years, including


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Pediatrics_Nelson. However, approximately 50% of DM patients have mental retardation. In addition, children with congenital DM experience a second progressive phase of the disease in the teen years, including potentially fatal cardiac arrhythmias.


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Pediatrics_Nelson. Diagnosis is established by genetic testing. Other Forms of Childhood Muscle Disease Congenital muscular dystrophies (CMDs) refer to a group of genetically determined conditions that present in infancy or early childhood. The most common subtypes include merosin-deficient congenital muscular dystrophy, Ullrich congenital muscular dystrophy, and the dystroglycanopathies. The characteristic clinical features include hypotonia, extremity weakness, delayed motor development, and congenital contractures. Diagnosis is established through the combination of elevated serum CK and dystrophic changes detected on muscle biopsy. In most individuals, the disease course is slow or nonprogressive, although many children with CMD are wheelchair dependent and require some type of respiratory support. Contractures and scoliosis are often progressive and severely worsen; respiratory status diminishes with age.


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Pediatrics_Nelson. Emery-Dreifuss muscular dystrophy (EDMD), also known as humeroperoneal muscular dystrophy, can be inherited as an X-linked recessive, autosomal dominant, or autosomal recessive disorder. Symptoms typically begin in childhood, although adult onset has been noted. Patients may experience early contractures, slowly progressive humeroperoneal muscle weakness or wasting, and cardiac disease with conduction defects and arrhythmias. EDMD is associated with mild elevations of serum CK levels, abnormal electrocardiograms (ECG), characteristic changes on muscle imaging, and abnormal but nonspecific muscle biopsies. There are no disease-specific modifying therapies for EDMD, although early placement of defibrillators in patients with abnormal ECGs reduces the incidence of sudden death.


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Pediatrics_Nelson. Several forms of limb-girdle muscular dystrophy (LGMD) have been described, which are usually inherited in an autosomal recessive pattern. Depending on the subtype of LGMD, presentation can be throughout childhood. A subset of children will have a Duchenne-like presentation. LGMD primarily affects muscles of the hip and shoulder girdles. Distal muscles may later become weak and atrophic. Many children with LGMD will lose the ability to ambulate. Some may also have progressive cardiac and respiratory failure.


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Pediatrics_Nelson. Facioscapulohumeral dystrophy is an autosomal dominant myopathy. Weakness first appears in the facial and shouldergirdle muscles. Shoulder weakness results in the characteristicobservation of scapular winging, which can often be asymmetric. Patients have mild ptosis, a decrease in facial expression,inability to pucker the lips or close eyes during sleep, neckweakness, difficulty in fully elevating the arms, and thinness ofupper arm musculature. Progression is slow, although childrenoften have a more severe presentation and can have significantdisability related to upper extremity weakness and dysfunction.


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Pediatrics_Nelson. Congenital myopathies (CM) are a relatively common group (prevalence approximately 1:20,000) of nondystrophic muscle disorders that, like congenital muscular dystrophies, most typically present in infancy with hypotonia and weakness. Additional signs and symptoms include congenital contractures, hip subluxation/dislocation, small/atrophic muscles, thin body habitus, and characteristic facial appearance (the “myopathic facies”). Symptoms are often nonprogressive or only slowly progressive, although children often have severe lifelong disabilities including wheelchair dependence, severe scoliosis, and respiratory failure. Clinical finding may distinguish CMDs and other dystrophies (e.g., involvement of the facial musculature in congenital myopathies). Diagnosis is ultimately established based on laboratory studies, biopsy findings, and genetic test results. Histopathologic subtypes are distinguished by characteristic features on muscle biopsy, the most common being nemaline myopathy,


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Pediatrics_Nelson. on laboratory studies, biopsy findings, and genetic test results. Histopathologic subtypes are distinguished by characteristic features on muscle biopsy, the most common being nemaline myopathy, centronuclear myopathy, and core myopathy. More than 15 different genetic causes have been established for CMs. However, nearly 50% of cases are genetically unresolved. Although no specific therapies currently exist for any CM subtype, several promising therapies have shown efficacy in preclinical models of disease.


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Pediatrics_Nelson. Glycogen storage disease type II (Pompe disease) and musclecarnitine deficiency are discussed in Chapters 52 and 55. Several mitochondrial myopathies may present with hypotonia, ophthalmoplegia, and progressive weakness, but the phenotype ofthese disorders is broad (Chapter 57). Endocrine myopathies, including hyperthyroidism, hypothyroidism, hyperparathyroidism, and Cushing syndrome, are associated with proximalmuscle weakness. Periodic paralysis due to familial forms of hypokalemia or hyperkalemia produces episodic weakness. The diagnostic evaluation should be guided by the clinical history and physical examination (Chapter 179).


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Pediatrics_Nelson. Malignant hyperthermia is a life-threatening syndrome manifested by a rapid increase of body temperature, muscle rigidity, metabolic and respiratory acidosis, hypotension, arrhythmias, and convulsions. Acute episodes are precipitated by exposure to anesthetic agents in patients with a genetic predisposition. Patients with Duchenne muscular dystrophy, central core myopathy, and other myopathies are susceptible, although malignant hyperpyrexia can also occur in children without muscle disease as an autosomal dominant genetic disorder. A family history of unexplained death during anesthesia is often noted. Serum CK levels rise and myoglobinuria can result in tubular necrosis and acute renal failure. Diagnosis of idiopathic malignant hyperthermia is possible with genetic testing or an in vitro muscle contraction test that reveals excessive tonic contracture on exposure to halothane and caffeine. Treatment consists of IV dantrolene, sodium bicarbonate, and cooling.


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Pediatrics_Nelson. The clinical distinction between upper and lower motor neuron disorders in infants is blurred because incomplete myelinization of the developing nervous system limits expression of many of the cardinal signs, such as spasticity. The two critical clinical points are whether the child is weak and the presence or absence of deep tendon reflexes. Hypotonia and weakness coupled with depressed or absent deep tendon reflexes suggest a neuromuscular disorder. A stronger child with brisk reflexes suggests an upper motor neuron source for the hypotonia. Causes of neonatal weakness are outlined earlier. A diagnostic algorithm for infants with hypotonia or weakness is presented in Figure 182-1. Available @ StudentConsult.com Some infants who appear to move well when supine in theircribs are floppy when handled or moved. When lifted, their Dysmorphic? CK, cDM1, SMA Brain MRI S MRI CK, PWS No Diagnosis? Diagnosis?


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Pediatrics_Nelson. Dysmorphic? CK, cDM1, SMA Brain MRI S MRI CK, PWS No Diagnosis? Diagnosis? Figure 182-1 Evaluation of an infant with hypotonia. cDM1, Congenital myotonic dystrophy; CK, creatine kinase; CMS, chromosomal microarray analysis; EMG, electromyelogram; MRI, magnetic resonance imaging; NCV, nerve conduction velocity; PWS, Prader-Willi syndrome; SMA, spinal muscular atrophy. (Courtesy James Dowling, MD.) heads flop, they slip through at the shoulders, do not supportweight on their legs, and form an inverted U in prone suspension (Landau posture). When placed prone as neonates,they may lie flat instead of keeping their arms and legs flexed.Passive tone is decreased, but reflexes are normal. Hypotonia may be associated with significant cerebral disease or maybe a benign phenomenon that is outgrown (Table 182-4). The most common cause of hypotonia is hypoxic-ischemic encephalopathy.


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Pediatrics_Nelson. Prader-Willi syndrome (PWS) presents with severe neonatal hypotonia; severe feeding problems leading to failure to thrive; small hands and feet; and, in boys, a small penis, small testicles, and cryptorchidism. Severe hyperphagia and obesity develop in early childhood. Approximately 60% to 70% of affected individuals have an interstitial deletion of paternalchromosome 15q11q13. PWS and trisomy 21 are the most common genetic causes of neonatal hypotonia. Infants who have a connective tissue disorder, such as Ehlers-Danlos syndrome, Marfan syndrome, or familial laxity of the ligaments, may exhibit marked passive hypotonia, ligamentous laxity, and increased skin elasticity. They have normal strength and cognition and achieve motor and mental milestones normally. They may have peculiar postures of their feet or unusual gaits.


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Pediatrics_Nelson. Infants with benign congenital hypotonia typically exhibit the condition at 6 to 12 months old with delayed gross motor skills. They are unable to sit, creep, or crawl, but have good verbal, social, and manipulative skills. Strength appears normal, and the infants can kick arms and legs briskly and bring their toes to their mouths. The children often display head lag, slip-through in ventral suspension, and floppiness of passive tone. The infant seems floppy from birth. The differential diagnosis includes upper and motor neuron disorders and connective tissue diseases. Extensive laboratory investigation is often unrevealing. Most of these children catch up to peers and Severe brain illness* Structural (hydrocephalus) Infectious Metabolic (e.g., anoxia or hypoglycemia) Intoxication through mother Connective tissue disorder Ehlers-Danlos syndrome Marfan syndrome Congenital laxity of ligaments *Common.


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Pediatrics_Nelson. Connective tissue disorder Ehlers-Danlos syndrome Marfan syndrome Congenital laxity of ligaments *Common. appear normal by 3 years of age. Often, other family members have exhibited a similar developmental pattern.


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Pediatrics_Nelson. The incidence of pediatric stroke is 2.5 to 10 per 100,000 children and is higher among neonates, approaching that of elderly patients. A wide spectrum of conditions can produce stroke in childhood (Table 182-5). Pediatric strokes may be due to ischemia (arterial ischemic stroke, cerebral sinovenous thrombosis) or hemorrhage. Arterial ischemic stroke (AIS)is focal brain infarction that results from occlusion of the arteries in the brain. The most common causes are vasculitis resulting in abnormal cerebral arteries (either autoimmune or infectious, such as vasculitis associated with meningitis) and cardioembolic infarcts due to congenital heart disease, sickle cell anemia, or coagulation disorders. Coagulation disorders also increase the risk of cerebral sinovenous thrombosis (CSVT), the occlusion of venous structures in the brain, which can result in ischemia as the cerebral venous pressure rises.


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Pediatrics_Nelson. CSVT can also be caused by infections or dehydration. Hemorrhagic strokes (HS) may be intraparenchymal (primary, or secondary bleeding after AIS) or associated with intra-ventricular, subarachnoid, subdural, or epidural bleeds. The most common causes of HS are vascular malformations, head trauma, and vasculitis. The acute onset of focal neurologic deficits in a child is strokeuntil proven otherwise. Symptoms may be subtle and nonspecific, which can lead to a delay in diagnosis. AIS typicallypresents with acute, focal neurologic deficits. Hemiparesis ismost common, but visual, speech, sensory, or balance deficits may be present. Unlike AIS in adults, focal seizures arequite common in childhood presentation of AIS. Similarly,neonatal AIS most often presents with acute symptomatic focal seizures (typically in the first day of life) or withencephalopathy.


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Pediatrics_Nelson. Symptoms of CSVT may progress more gradually and be more variable and nonspecific than AIS. In CSVT, acute focal deficits may be present, or the child may have progressive signs of elevated intracranial pressure, including headache, papilledema, diplopia (most often from cranial nerve VI palsy), seizures, lethargy, or confusion. HS tends to present acutely, with a sudden “thunderclap” headache. HS may also present with loss of consciousness, nuchal rigidity, focal deficits, or seizures and can be rapidly fatal. Congenital hemiplegia becomes apparent as infants develop, with decreased use of one side of the body, early handedness, or ignoring one side. Neuroimaging reveals an area of encephalomalacia in the contralateral cerebral hemisphere. The details of the child’s intrauterine, labor, delivery, and postnatal history often are unremarkable. The area of encephalomalacia may predispose the child to epilepsy.


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Pediatrics_Nelson. There are many conditions that mimic pediatric stroke, most of which are more common than AIS, HS, or CSVT. Some of these mimics are benign (migraine, psychogenic weakness, musculoskeletal abnormalities), but others require specific, prompt diagnosis and/or treatment (e.g., transient postictal weakness, intracranial infection, inflammatory disease of the central nervous system, tumor, or posterior reversible leukoencephalopathy syndrome).


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Pediatrics_Nelson. On initial presentation, acute neuroimaging is necessary. A noncontrast head computed tomography (CT) scan is highly sensitive to acute HS and can reveal larger, mature AIS; acute, nonhemorrhagic stroke may not be seen on routine CT. Therefore, MRI with diffusion-weighted imaging is required for most presentations. Angiography by magnetic resonance angiography (MRA) or CT angiography is used to confirm arterial occlusion in AIS and can identify underlying arteriopathy, vascular malformations, and aneurysms. Diagnosis of CSVT requires a high clinical suspicion and purposeful imaging of the cerebral venous system with venography by MRI or CT. If clinical assessment does not reveal the cause of the stroke, a complete laboratory investigation should be undertaken promptly based on suspected etiologies (see Table 182-5). Many children with AIS have more than one predisposing factor, so identifying one risk factor does not obviate the need for a complete evaluation.


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Pediatrics_Nelson. Treatment must focus on limiting secondary neuronal injuryand prevention of future strokes. Neuroprotection by maintaining control of temperature, blood pressure, glucose, andseizures is essential. Emergency thrombolysis with medications or catheterization is not yet established for children,but this is an area of active clinical research. Anticoagulants(IV heparin, subcutaneous low-molecular-weight heparin,oral warfarin) and platelet antiaggregants (aspirin) are usedfor secondary stroke prevention in some instances. For thosewith progressive CSVT, anticoagulation is the mainstay oftherapy. Long-term rehabilitation programs are required for most survivors.


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Pediatrics_Nelson. Ataxia is the inability to make accurate, smooth and coordinated movements, usually due to a dysfunction of the cerebellar pathways. If either the afferent (joint position senses)or efferent cerebellar connections (cerebellum through thalamus to cerebral cortex) are disturbed, the patient has ataxia.Truncal ataxia reflects disturbances of the midline cerebellar vermis (e.g., medulloblastoma, acute postinfectious cerebellarataxia, or ethanol intoxication). Appendicular ataxia reflects disturbances of the ipsilateral cerebellar hemisphere (e.g., cystic cerebellar astrocytoma). The most common causes of acuteataxia in childhood are postinfectious acute cerebellar ataxiaand drug intoxications. Discrete lesions within the posteriorfossa, tumors (e.g., medulloblastoma, ependymoma, cerebellar astrocytoma), multiple sclerosis, strokes, and hemorrhagesmay cause ataxia. Other causes include benign paroxysmalvertigo, head trauma, seizures, postictal states, migraine,paraneoplastic


Pediatrics_Nelson

Pediatrics_Nelson. cerebellar astrocytoma), multiple sclerosis, strokes, and hemorrhagesmay cause ataxia. Other causes include benign paroxysmalvertigo, head trauma, seizures, postictal states, migraine,paraneoplastic opsoclonus-myoclonus syndrome associated with neuroblastoma, and inborn errors of metabolism. Congenital disorders also may produce chronic, nonprogressiveataxia. There are a number of inherited ataxia syndromes(Table 183-1).


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Pediatrics_Nelson. Available @ StudentConsult.com Inhalants Drugs of abuse *Common. The usual symptoms of ataxia are a broad-based, unsteady gait (truncal ataxia) and intention tremor or dysmetria (overor undershooting of the target due to abnormal distance perception). An intention tremor worsens as the arm/hand approaches the target. Classically, these symptoms stem from disorders of the cerebellar pathways, but peripheral nerve lesions causing loss of proprioceptive inputs to the cerebellum (Guillain-Barré syndrome) may present with similar symptoms. In addition, weakness may intensify or mimic ataxia, so strength must be assessed, along with coordination. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Drug intoxication is the most common cause of acute ataxia among children. Overdosage with any sedative-hypnotic agentcan produce acute ataxia and lethargy, but ataxia without lethargyusually results from intoxication with ethanol or anticonvulsantdrugs. It is important to ask about any medications or drugs ofabuse the patient may have access to. Treatment is supportive.


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Pediatrics_Nelson. Postinfectious acute cerebellar ataxia may occur 1 to 3 weeks following varicella, infectious mononucleosis, mild respiratory or gastrointestinal viral illnesses, or other infections. The pathogenesis is uncertain and may represent either a direct viral infection of the cerebellum or, more likely, an autoimmune response precipitated by the viral infection and directed at the cerebellar white matter. Symptoms begin abruptly, causing truncal ataxia, staggering, and frequent falling. Dysmetria of the arms, dysarthria, nystagmus, vomiting, irritability, and lethargy may be present. Symptoms, which may be severe enough to prevent standing or sitting, usually peak within 2 days, then stabilize and resolve over several weeks. Cerebrospinal fluid (CSF) examination sometimes shows a mild lymphocytic pleocytosis or mild elevation of protein content. Brain magnetic resonance imaging may reveal cerebellar enhancement. No specific therapy is available except to prevent injury during the ataxic


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Pediatrics_Nelson. pleocytosis or mild elevation of protein content. Brain magnetic resonance imaging may reveal cerebellar enhancement. No specific therapy is available except to prevent injury during the ataxic phase.


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Pediatrics_Nelson. Brain tumors are the second most common neoplasm in children. About 50% arise from within the posterior fossa. Tumors that arise in the posterior fossa or brainstem produce progressive ataxia with headache that may be acute or gradual in onset. There is a progressive worsening over days, weeks, or months, typically with associated signs and symptoms of elevated intracranial pressure. The ataxia and dysmetria may result from primary cerebellar invasion or from obstruction of the CSF pathways (aqueduct of Sylvius or fourth ventricle) with resultant hydrocephalus. The most common tumors in this region include medulloblastoma, ependymoma, cerebellar astrocytoma, and brainstem glioma.


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Pediatrics_Nelson. Rarely, a neuroblastoma located in the adrenal medulla or anywhere along the paraspinal sympathetic chain in the thorax or abdomen is associated with degeneration of Purkinje cells and the development of severe ataxia, dysmetria, irritability, myoclonus, and opsoclonus. An immunologic reaction directed toward the tumor may be misdirected to attack Purkinje cells and other neuronal elements. The myoclonic movements are irregular, lightning-like movements of a limb or the head. Opsoclonus is a rapid, multidirectional, conjugate movement of the eyes, which suddenly dart in random directions. The presence of opsoclonus-myoclonus in a child should prompt a vigorous search for an occult neuroblastoma. Several rare inborn errors of metabolism can present with intermittent episodes of ataxia and somnolence. These include Hartnup disorder, maple syrup urine disease, mitochondrial disorders, abetalipoproteinemia, and vitamin E deficiency.


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Pediatrics_Nelson. Difficulty walking with a severe staggering gait is one manifestation of acute labrynthitis, but the diagnosis usually is clarified by the associated symptoms of a severe sense of spinning dizziness (vertigo), nausea and vomiting, and associated signs of pallor, sweating, and nystagmus. Ataxia-telangiectasia, an autosomal recessive genetic disorder, is the most common of the degenerative ataxias. Affected patients present with ataxia around age 2 years, progressing to loss of ambulation by adolescence. In mid-childhood, telangiectasia is evident over the sclerae, nose, ears, and extremities. Abnormalities in immune function and greatly increased risk of lymphoreticular tumors result in early death.


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Pediatrics_Nelson. Friedreich ataxia is a relentlessly progressive, autosomalrecessive disorder. Children present in the late elementary yearswith ataxia, dysmetria, dysarthria, diminished proprioceptionand vibration, absent deep tendon reflexes, and nystagmus,and many develop hypertrophic cardiomyopathy and skeletalabnormalities (high-arched feet, hammer toes, kyphoscoliosis). Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Movement disorders or dyskinesias are a diverse group of entities associated with abnormal excessive, exaggerated, chaotic, or explosive movements of voluntary muscles. They are generally the result of abnormalities of the extrapyramidal system orthe basal ganglia. Movement disorders in children are typicallyhyperkinetic (increased movement) patterns. The abnormalmovements are activated by stress and fatigue and often disappear in sleep. They are typically diffuse and migratory (chorea)but may be isolated to specific muscle groups (segmental myoclonus, palatal myoclonus) and may not disappear in sleep.


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Pediatrics_Nelson. Chorea is a hyperkinetic, rapid, unsustained, irregular, purposeless movement that seems to flow from one body part to another. Affected patients demonstrate difficulty keeping the tongue protruded or maintaining grip (milkmaid grip).Patients often attempt to incorporate the involuntary movements into more purposeful movements, making them appear fidgety. Choreiform movement abnormalities may be autoimmune/parainfectious, infectious, genetic, structural, metabolic or toxic in origin (Table 183-2). The movements may occur Autoimmune/parainfectious (acute rheumatic fever,* systemic lupus erythematosus) Infectious (human immunodeficiency virus, neurosyphilis, scarlet fever, encephalitis) Genetic (Huntington disease, ataxia-telangiectasia) Structural (stroke, neoplasm) Metabolic/toxic (hepatic/renal failure, hyperthyroidism) Drug induced


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Pediatrics_Nelson. Physiologic* Essential tremor* Hereditary, degenerative (Huntington disease, Wilson disease) Stroke Metabolic (hyperthyroidism, hepatic encephalopathy, electrolyte disturbances) Drugs/toxins* (caffeine, bronchodilators, amphetamines, tricyclic antidepressants) Psychogenic tremor alone or as part of a more extensive neurologic disorder (e.g., Sydenham chorea, Huntington chorea, systemic lupus erythematosus, or encephalitis). Athetosis is a hyperkinetic, slow, coarse, writhing movement that is more pronounced in distal muscles. Athetosis is seen frequently in combination with chorea (choreoathetosis) and usually is present in conjunction with other neurologic signs. It may be seen in virtually all the disorders mentioned for chorea. Many children with mixed forms of cerebral palsy have spasticity and choreoathetosis.


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Pediatrics_Nelson. Dystonia is characterized by abnormally sustained muscle contraction, causing twisting motion (torsion spasm) and repetitive movements or abnormal postures. Cerebral palsy is the most common cause of dystonia among children, usually associated with basal ganglia or thalamic lesions. Many genetic mutations have been implicated in primary dystonias. Antipsychotics and antiemetics can produce acute dystonic reactions, typically involving the face and neck with torticollis, retrocollis, tongue protrusions, and oculogyric crises (eye rotation). Tardive dyskinesia usually is associated with chronic antipsychotic drug use and presents with characteristic face involvement (tongue thrusting, chewing).


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Pediatrics_Nelson. Tremor is a hyperkinetic, rhythmic, oscillatory movement caused by simultaneous contractions of antagonistic muscles. The amplitude and frequency are regular. Inchildren, tremor is usually due to a physiologic tremor,or essential tremor. Essential tremor is the most common movement disorder in adults, and half report onset inchildhood. Other causes of tremor include thyrotoxicosis,hypoglycemia, or drugs (caffeine, bronchodilators, amphetamines, tricyclic antidepressants).


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Pediatrics_Nelson. Myoclonus is a hyperkinetic, brief flexion contraction of a muscle group, resulting in a sudden jerk. Myoclonus may be epileptic or nonepileptic. Nonepileptic myoclonus is distinguished from tremor in that it is a simple contraction of an agonist muscle, whereas tremor is a simultaneous contraction of agonist and antagonist muscles. Myoclonus is seen as a manifestation of various epilepsies and of infectious, toxic, and metabolic encephalopathies. Benign myoclonus is commonly observed during sleep and may be particularly pronounced in neonates.


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Pediatrics_Nelson. Tics are rapid, purposeless, involuntary, stereotyped movements and typically involve the face, eyes, shoulder, and arm. Examples of simple motor tics include blinking, nose twitching, and extremity jerking. Complex motor tics are more orchestrated movements, including head shaking, gesturing, or jumping. Phonic tics may be simple (grunting, throat clearing) or complex (uttering words, phrases). Approximately 25% of children have transient tics. Most tic disorders in children are transient and not intrusive into the child’s life, but may be a source of parental anxiety. Occasionally, tics may be unmasked by stimulant agents. Persistent motor tics (>12 months) in association with vocal tics are characteristic of Tourette syndrome, a chronic tic disorder that usually begins before age 7 years. The pathophysiology underlying tics is unknown, but a family history of tics is elicited in more than 50% of cases. Comorbid features, such as obsessive-compulsive disorder and


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Pediatrics_Nelson. before age 7 years. The pathophysiology underlying tics is unknown, but a family history of tics is elicited in more than 50% of cases. Comorbid features, such as obsessive-compulsive disorder and attention-deficit/hyperactivity disorder, may be present in half of children with Tourette disorder (Chapters 13, 19). Tic disorders are clinical diagnoses, and neurodiagnostic studies have limited value. Many children with tic disorders or Tourette syndrome are unperturbed by their tics and require no therapy. Others may benefit from psychological support, including habit reversal training, and pharmacologic therapy with α-adrenergic receptor agonists (clonidine) or neuroleptics (pimozide, haloperidol, risperidone). Chronic tic disorders wax and wane regardless of intervention and most often improve substantially or resolve entirely by late adolescence.


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Pediatrics_Nelson. Consciousness represents awareness of self and environment (place and time). Arousal represents the system that initiates and maintains consciousness. Consciousness is mediated by the cerebral cortex; arousal is mediated by the reticular activating system extending from the mid pons through the mid-brain and hypothalamus to the thalamus. Lethargic patients have difficulty maintaining an arousedstate. Patients who are obtunded have decreased arousal but are responsive to stimuli. Stupor is a state of responsivenessto pain but not to other stimuli. Coma is a state of unresponsive unconsciousness and is caused by dysfunction of the cerebral hemispheres (bilaterally), the brainstem, or bothsimultaneously. Acute Disorders of Consciousness Available @ StudentConsult.com


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Pediatrics_Nelson. Acute Disorders of Consciousness Available @ StudentConsult.com Acute changes in consciousness vary in degree from mild lethargy and confusion to deep coma. In childhood, the most common causes of coma are toxins, infections, head trauma, hypoxia-ischemia (cardiac arrest, near-drowning), and seizure (postictal state, subclinical status epilepticus) (Table 184-1). The most common cause of long-term morbidity in a patient with depressed consciousness is hypoxia; therefore, airway, breathing and circulation are addressed first. Vital signs, including pulse oximetry, must be assessed. A glucose level should also be checked immediately because hypoglycemia is a rapidly treatable cause of altered mental status. Physical examination searches for clues as to the cause of altered consciousness, such as unusual odors, needle tracts, trauma, or signs of dehydration or organ system failure.


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Pediatrics_Nelson. Breathing patterns may provide important clues to the depth, neurologic localization, and etiology of the depressed consciousness. In Cheyne-Stokes respiration, a period of Gastrointestinal (intussusception) Vasculitis (systemic lupus erythematosus) Hepatic failure Hypertensive encephalopathy Reye syndrome Endocrine disorders (adrenal insufficiency, thyroid disorders) Renal disorders (uremia) Hypoglycemia Hyponatremia or its correction Hypernatremia or its correction Hyperosmolality or its correction Hypercapnia Hyperammonemia Inborn errors of metabolism Diabetes mellitus—ketoacidosis or hypoglycemia Routine laboratory testing Glucose Sodium, potassium, chloride, bicarbonate, BUN, creatinine, AST, ALT, blood gases, ammonia Blood and urine analyses for toxic substances CSF analysis including opening pressure, white and red blood cell counts, protein, glucose, and culture (± viral PCR testing) Neuroimaging Head CT Brain MRI, MRA, MRV


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Pediatrics_Nelson. CSF analysis including opening pressure, white and red blood cell counts, protein, glucose, and culture (± viral PCR testing) Neuroimaging Head CT Brain MRI, MRA, MRV Secondary laboratory testing (if cause remains unknown) Lead level, pyruvate, lactate, serum amino acids, urine organic acids, acylcarnitine profile ALT, Alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CSF, cerebrospinal fluid; CT, computed tomography; EEG, electroencephalogram; MRI/MRA/MRV, magnetic resonance imaging/angiography/venography; PCR, polymerase chain reaction; PT, prothrombin time; PTT, partial thromboplastin time.


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Pediatrics_Nelson. hyperventilation with a crescendo-decrescendo pattern alter-The detailed neurologic examination of a comatose patient nates with a shorter period of apnea and is due to the loss of focuses on the integrity of the brainstem which is the location cerebral, thalamic, or hypothalamic modulation of respiration. of the reticular activating system, mediating arousal. Pupillary This pattern also can be seen in patients with metabolic disor-responses assess the midbrain function. Eye movements are ders, heart failure, or primary respiratory disease. A mid-brain observed or elicited with the doll’s eye maneuver (oculocelesion yields central neurogenic hyperventilation, which phalic response) (Chapter 179) or cold caloric stimulation consists of sustained rapid deep breathing. Gasping respira-(oculovestibular response). If the oculocephalic responses tions are irregularly irregular and indicate dysfunction of the are not elicited or unclear, cold water is flushed into the exterlower brainstem


Pediatrics_Nelson

Pediatrics_Nelson. response). If the oculocephalic responses tions are irregularly irregular and indicate dysfunction of the are not elicited or unclear, cold water is flushed into the exterlower brainstem (medulla). Gasping is ominous and usually is nal ear canal. In a conscious person, this maneuver elicits followed by terminal apnea. nystagmus to the opposite side and extreme vertigo with vom-


Pediatrics_Nelson

Pediatrics_Nelson. The Glasgow Coma Scale (see Table 42-2) can be used to iting. In a comatose patient, cold water irrigation into the ear assess unresponsive patients regarding their best verbal and canal elicits a tonic eye deviation toward the ear irrigated if motor responses and eye opening to stimulation with a score the brainstem is functioning and the patient is not brain dead. of 3 to 15 points. With complete loss of oculomotor function, the eyes remain in the center of the orbit regardless of any stimulation, indicating brainstem failure.


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Pediatrics_Nelson. Body posture at rest and after noxious stimulation can indicate the anatomic level responsible for the alteration of consciousness. Mildly altered mental status may be manifested by a comfortable sleeping posture. Frequent spontaneous readjustments of position, yawns, and sighs are observed. Patients who lie in a flat, extended, unvarying position with eyes half-open exhibit a deeper coma. An asymmetrical posture suggests motor dysfunction of one side. This asymmetry may be subtle, such as mild external rotation of the affected leg.


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Pediatrics_Nelson. Posturing in response to noxious stimulation indicates moreserious neurologic conditions. Decorticate posturing consists of rigid extension of the legs and feet, flexion and supinationof the arms, and fisting of the hands. It indicates bilateral cortical or subcortical abnormalities or herniation, with preservedbrainstem function. Decerebrate posturing (rigid extensionand internal rotation of legs and arms) indicates a midbrainabnormality and is classically associated with herniation ortoxic-metabolic abnormalities. These postures may be exhibitedunilaterally or bilaterally. A structural cause is likely when posturing is asymmetric, whereas symmetric posturing may bemore likely with underlying toxic-metabolic etiologies.


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Pediatrics_Nelson. The evolution of change in consciousness is an important clue to the etiology. A detailed history and physical examination usually provide sufficient clues to differentiate among the three major diagnostic categories producing coma: metabolic/toxic, infectious, and structural. In most clinical situations, the cause of coma is readily identified.


Pediatrics_Nelson

Pediatrics_Nelson. Metabolic derangements are common causes of altered mental status. Disturbances of blood chemistries (glucose, sodium, calcium, bicarbonate, blood urea nitrogen, ammonia) may produce depressed mental status. Metabolic causes of acute coma are suggested by spontaneous fluctuations in the level of consciousness, tremors, myoclonus, asterixis, visual and tactile hallucinations, and deep coma with preservation of pupillary light reflexes. Acute metabolic or toxic disorders usually produce a hypotonic, limp state, but hypertonia, rigidity, and decorticate and decerebrate posturing are sometimes observed in coma caused by hypoglycemia, hepatic encephalopathy, and short-acting barbiturates. A subacute course of somnolence progressing to difficulty arousing from a deep sleep (stupor) over hours suggests drug intoxication or organ system failure (kidney, liver) producing a metabolic encephalopathy. Care must be taken to investigate background medical conditions that may produce a decline in


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Pediatrics_Nelson. suggests drug intoxication or organ system failure (kidney, liver) producing a metabolic encephalopathy. Care must be taken to investigate background medical conditions that may produce a decline in consciousness (e.g., diabetes mellitus, leukemia, kidney failure, liver disease). Intoxication and ingestion are common causes of acute alteration of consciousness, and a thorough history must be taken to search for the offending agent (Chapter 45). A history of social and emotional difficulties, drug abuse, or depression raises concern for self-inflicted injury or toxic ingestion.


Pediatrics_Nelson

Pediatrics_Nelson. Central nervous system infection, such as meningitis or encephalitis, usually causes abrupt alteration of mental status, althoughviral meningoencephalitis (particularly herpes simplex virus) canpresent with subacute alterations in mental status. The presenceof fever, petechiae, chills, and sweats suggests infection. Prodromal photophobia and pain on movement of the head or eyes aresymptoms of meningeal irritation. Premonitory symptoms, suchas abdominal pain, diarrhea, sore throat, conjunctivitis, cough, orrash, point toward viral encephalitis or a postinfectious syndromeas the cause of the altered consciousness.


Pediatrics_Nelson

Pediatrics_Nelson. Structural processes, such as hemorrhage, infarction, or acute hydrocephalus, can cause sudden depressed consciousness in children. An evolution of headache and morning vomiting suggests increased intracranial pressure (ICP). A gradual fading of alertness or declining school performance over preceding weeks suggests an expanding intracranial mass, subdural hematoma, or chronic infection (e.g., tuberculous meningitis, human immunodeficiency virus). Deprivation of oxygen to the brain, caused by either deficient oxygen in the blood (hypoxemia) or deficient delivery of blood to the brain (ischemia), impairs consciousness.


Pediatrics_Nelson

Pediatrics_Nelson. Papilledema or paralysis of cranial nerves III or VI in a patientwith depressed consciousness is strong evidence of elevatedICP, a medical and neurosurgical emergency. Herniations occur under the falx, through the tentorial notch, or into theforamen magnum (Table 184-2). Recognition of the signsassociated with the major herniation syndromes can be lifesaving, if emergent neuroimaging and treatment are initiated.Uncal herniation implies displacement of the mesial temporal lobe over the tentorial edge, producing a unilateral third


Pediatrics_Nelson

Pediatrics_Nelson. Transtentorial Unilateral Supratentorial mass lesions, Downward displacement of supratentorial Headache (uncal) or bilateral diffuse brain swelling, brain tissue into infratentorial compartment Altered consciousness focal edema, or acute (below tentorium), compressing the cerebral Dilated ipsilateral pupil hydrocephalus peduncles, midbrain, third cranial nerve, and Cranial nerve III palsy posterior circulation Hemiparesis Decerebrate posturing Cushing triad Respiratory arrest nerve palsy (“blown pupil”) and hemiparesis (which can beipsilateral, because of compression of the contralateral cerebralpeduncle, or contralateral if the uncus compresses the ipsilateral peduncle). Transtentorial (or central) herniation occurs with gradual downward pressure from the diencephalonthrough the tentorium, resulting in compression of the brain-stem (first midbrain, then progressing to pons and medulla). Aprogressive loss of consciousness accompanied by a characteristic progression of motor,


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Pediatrics_Nelson. tentorium, resulting in compression of the brain-stem (first midbrain, then progressing to pons and medulla). Aprogressive loss of consciousness accompanied by a characteristic progression of motor, oculomotor, pupillary, and respiratory signs indicates incipient transtentorial herniation.


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Pediatrics_Nelson. Evaluation is guided by the history and physical examination(see Table 184-1). Computed tomography (CT) remains thepreferred imaging technique in emergency situations because itcan be performed rapidly and accurately identifies acute hemorrhages, large space-occupying lesions, edema, and shifts ofthe midline. The initial head CT scan is done without contrast to identify blood and calcifications. Contrast can be administered to identify inflammatory and neoplastic lesions, but is notusually required for identification of major lesions. Several metabolic derangements (hepatic encephalopathy, Reye syndrome,hyponatremia, lead encephalopathy, diabetic ketoacidosis, andhypoxic-ischemic injury) may give rise to severe elevations of ICPwithout producing obvious CT abnormalities. Lumbar puncture (LP) in a patient with elevated ICP can result in transtentorial herniation, so imaging should be performed before LP ifelevated ICP is suspected, especially if there are any focal neurological


Pediatrics_Nelson

Pediatrics_Nelson. (LP) in a patient with elevated ICP can result in transtentorial herniation, so imaging should be performed before LP ifelevated ICP is suspected, especially if there are any focal neurological deficits on exam. If trauma or immersion injuries aresuspected, neck manipulation should be avoided until cervicalspine imaging excludes vertebral fracture or subluxation.


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Pediatrics_Nelson. Examination of the cerebrospinal fluid (CSF) may establishthe cause of the alteration of consciousness. Appropriate neuroimaging should be performed to ensure that no added injury islikely to be inflicted with LP. The presence of red blood cells inthe CSF may suggest primary subarachnoid hemorrhage, parenchymal hemorrhage, or hemorrhagic infection (herpes simplexvirus), or it may be due to a traumatic procedure. White bloodcells in the CSF usually denote infectious meningitis or meningoencephalitis but may also be associated with vasculitis or parainfectious syndrome. Elevated CSF protein is seen in patientswith meningeal inflammation or tumors, and abnormal CSFglucose levels are also markers of infection and inflammation.


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Pediatrics_Nelson. The etiology of altered mental status determines the treatment. Ingestions may necessitate gastric lavage, charcoal administration, forced diuresis, dialysis, or specific antidotes (Chapter 45). Infections are treated with appropriate antibiotics or antiviral agents (Chapter 95). If mental status changes are due to increased ICP, acute medical interventions (osmotic agents, steroids, hyperventilation) must be instituted, emergent neuroimaging performed, and urgent neurosurgical consultation obtained. Structural brain lesions may necessitate medical treatment of increased ICP or surgical excision.


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Pediatrics_Nelson. The outcome of altered mental status relates to many variables, including etiology. Intoxication typically carries a good prognosis, whereas hypoxia carries a poor prognosis. Other prognostic factors include the duration of coma and the age of the patient; children have better outcomes than adults. Complete recovery from traumatic coma of several days’ duration is possible in children; however, many survivors of prolonged coma are left in a persistent vegetative state or with severe neuropsychiatric disability. Transient, Recurrent Depression of Consciousness


Pediatrics_Nelson

Pediatrics_Nelson. Transient, Recurrent Depression of Consciousness Episodic alteration or depression of consciousness with full recovery is usually due to seizure, migraine, syncope, or metabolic abnormality (hypoglycemia). Consciousness can be impaired during seizures or in the postictal state. Nonconvulsive (subclinical) status epilepticus (generalized or focal) can directly impair consciousness and is a common complicating factor for patients with acute neurological disorders (head trauma, meningitis, following convulsive status epilepticus). Some patients may have a prolonged postictal state after an unrecognized seizure. Basilar artery or confusional migraines can last hours and be accompanied by agitation, ataxia, cortical blindness, vertigo, or cranial nerve palsies. Headache may precede or follow the neurologic signs.


Pediatrics_Nelson

Pediatrics_Nelson. Syncope is one of the most common causes of abrupt, episodic loss of consciousness. Neurocardiogenic syncope, cardiac arrhythmia, or an obstructive cardiomyopathy can cause recurrent episodes of loss of consciousness. Two thirds of children with syncope have irregular, myoclonic movements as they lose consciousness (anoxic seizures), which much be distinguished from epilepsy (unprovoked seizures). Children with unexplained syncope require a complete cardiac examination (Chapter 140). Metabolic derangements, particularly hypoglycemia, give rise to episodes of lethargy, confusion, seizures, or coma. Several other metabolic disorders cause recurrent bouts of hyperammonemia (Chapter 53). Symptoms include nausea, vomiting, lethargy, confusion, ataxia, hyperventilation, and coma.


Pediatrics_Nelson

Pediatrics_Nelson. Following head injury, children may have immediate depression of consciousness and neurologic deficits or may be completely alert without any immediate signs of neurologic injury. Most serious trauma results from motor vehicle crashes, sports, recreation-related injuries, and violence. Head trauma may result in concussion, posttraumatic intracranial hemorrhage, skull fractures, or cranial nerve or cervical spine injuries. Head injury, or other injuries, with associated retinal hemorrhages in infants and young children should raise the suspicion of abusive head trauma. Concussion is the process in which traumatic forces on the brain result in the rapid onset of short-lived neurologic impairment that typically resolves spontaneously. Patients may have signs or symptoms in one or more domain: somatic (headache), cognitive (slowed reaction times, feeling like they are in a fog, poor attention), emotional (lability, irritability), sleep


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Pediatrics_Nelson. Return to play protocol follows a stepwise progress with each step taking 24 hours. The athlete should continue to the next level if asymptomatic at the current level. 1. No activity, complete physical and mental rest. 2. Light aerobic exercise such as walking or stationary cycling; no resistance training. 3. Sport-specific exercise (skating in hockey, running in soccer). 4. Noncontact, more progressive training drills; resistance training. 5. Full-contact practice after medical clearance. 6. Game play. Modified from McCrory P, Meeuwisse W, Johnston K, et al: Consensus statement on concussion in sport: the 3rd International Conference on Concussion in Sport, held in Zurich, November 2008. Br J Sports Med 2009;43:i76-i84.


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Pediatrics_Nelson. Concussion in Sport, held in Zurich, November 2008. Br J Sports Med 2009;43:i76-i84. disturbance (drowsiness), or physical signs (loss of consciousness, amnesia). Acute symptoms usually reflect a functional disturbance rather than structural injury, and no abnormalities are seen on standard imaging. The majority of concussions resolve within 10 days, although the recovery may be slower in children, and in a small percentage of cases, the symptoms are prolonged. Repeated concussions, especially within a short time frame (days or weeks) carry a significant risk of permanent brain injury (second impact syndrome). Children must not be permitted to resume physical activities until well after the symptoms resolve (Table 184-3).


Pediatrics_Nelson

Pediatrics_Nelson. Head trauma can result in epidural, subdural, parenchymal, and subarachnoid intracranial hemorrhages, as well as brain contusions (Table 184-4). Symptoms include headache, vomiting lethargy, decreased consciousness and seizures. The classic presentation of epidural hemorrhages involves a lucid interval, where, following primary brain injury, a child has a decreased level of consciousness, then returns to normal for several hours before developing rapidly progressive neurologic symptoms. Subdural hemorrhages may result from direct trauma or rotational forces from vigorous shaking (shaken baby syndrome). In neonates and infants with open fontanelles, signs and symptoms may be absent or nonspecific. Occasionally, epidural, subdural, or intracranial hemorrhage or a rapid, life-threatening increase in ICP develops unexpectedly in children due to cerebral edema.


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Pediatrics_Nelson. Skull fractures may be linear, diastatic (spreading the suture), depressed (an edge displaced inferiorly), or compound (bone fragments breaking the skin surface). Linear and diastatic fractures necessitate no treatment, but indicate trauma capable of producing an underlying hematoma. Small, depressed fractures have the same significance as linear fractures, but if the depression is more than 0.5 to 1 cm, surgical elevation of bone fragments and repair of associated dural tears are generally recommended. Compound fractures or penetrating injuries necessitate emergent surgical debridement and tetanus Onset over minutes to hours Lucid interval followed by progressive neurologic deficits Lens-shaped extracerebral hemorrhage compressing brain Chronic subdural Onset over weeks to months Anemia, macrocephaly Seizures, vomiting Crescentic, low-density mass on CT


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Pediatrics_Nelson. Chronic subdural Onset over weeks to months Anemia, macrocephaly Seizures, vomiting Crescentic, low-density mass on CT Focal neurologic deficits Brain swelling with transtentorial herniation CT findings: multifocal low-density areas with punctate hemorrhages Surgical evacuation or observation Prognosis good with prompt treatment, otherwise poor Subdural taps or subdural shunt as necessary Prognosis can be good Medical treatment of elevated intracranial pressure * Prognosis guarded CT, Computed tomography. *Mannitol, elevation of head of bed, diuresis, hyperventilation, steroids. prophylaxis. The risk of associated brain contusion and early seizures is high in compound fractures.


Pediatrics_Nelson

Pediatrics_Nelson. prophylaxis. The risk of associated brain contusion and early seizures is high in compound fractures. Skull fractures may present with localized swelling and pain; subcutaneous bleeding over the mastoid process (Battle sign) or around the orbit (raccoon eyes); blood behind the tympanic membrane (hemotympanum); or CSF leak from the nose (rhinorrhea) or ear (otorrhea). Rarely, a few weeks to months after linear skull fractures, a soft, pulsatile scalp mass is palpable; radiographically, the fracture edges are separated by a soft tissue mass that consists of fibrotic tissue and accumulated brain and meningeal tissue and, possibly a leptomeningeal cyst. The recommended treatment of leptomeningeal cysts involves surgical excision of abnormal tissue and dural repair.


Pediatrics_Nelson

Pediatrics_Nelson. CSF leak occurs when a skull fracture tears adjacent dura, creating communications between the subarachnoid space and the nose, paranasal sinuses, mastoid air cells, or ear. Clear fluid that leaks from the nose or ear after head trauma is presumed to be CSF until proved otherwise. The presence of air within the subdural, subarachnoid, or ventricular space also indicates a dural tear and open communication between the nose or paranasal sinuses and brain. In most cases, the dura heals spontaneously when the patient’s head is kept elevated. Patients with CSF leaks are at risk for the development of meningitis or extradural abscesses. If the leak persists or recurs or if meningitis develops, the dura is surgically repaired. Cranial nerve palsies, secondary to a laceration or contusion of the cranial nerves, may result from a skull fracture and may be transitory or permanent. Longitudinal fracture of the petrous bone produces a conductive hearing loss and facial palsy, which begin hours


Pediatrics_Nelson

Pediatrics_Nelson. cranial nerves, may result from a skull fracture and may be transitory or permanent. Longitudinal fracture of the petrous bone produces a conductive hearing loss and facial palsy, which begin hours after the injury and usually resolve spontaneously. Transverse petrous fractures produce sensorineural hearing loss and immediate facial palsy with a poor prognosis for spontaneous recovery. Disruption of the ossicular chain can cause hearing loss and may necessitate surgery. Vestibular disturbances, producing prolonged posttraumatic vertigo, are extremely common. Permanent loss of olfaction after a head injury is the result of a rupture of the thin olfactory nerves within the cribriform plate. Disruption of cranial nerves III, IV, and VI produces ophthalmoplegia, diplopia, and head tilt. Even seemingly minor head injuries can produce sixth nerve palsy with medial deviation (or incomplete abduction) of one or both eye(s).


Pediatrics_Nelson

Pediatrics_Nelson. Other Complications of Head Trauma Cervical spine injuries must be suspected in any unconscious child, especially if bruises are present on the head, neck, or back. In conscious children, findings of neck or back pain, burning or stabbing pains radiating to the arms, paraplegia, quadriplegia, or asymmetrical motor or sensory responses of arms or legs suggest spinal cord injury. Cervical spine injury (displaced or fractured vertebra) may result in complete transection of the cord with spinal shock, loss of sensation, and flaccid paralysis. A contused cord (without vertebral abnormality) may present in a similar manner. Any patient with a clinical or radiologic abnormality of the spine requires immediate spine and cardiopulmonary stabilization and neurosurgical consultation.


Pediatrics_Nelson

Pediatrics_Nelson. Posttraumatic seizures are divided into one of three patterns: impact seizures, early posttraumatic seizures, and lateposttraumatic seizures. Impact seizures occur within secondsof the injury and are presumed to reflect a direct mechanical stimulation to the cortex. The prognosis is excellent, andlikelihood of later epilepsy is negligible. Early posttraumaticseizures occurring within the first week of the head injury arelikely the result of a localized area of cerebral contusion or edema. The long-term prognosis for these seizures is quitefavorable. Late posttraumatic seizures arise more than a weekafter the trauma and most likely indicate an area of corticalgliosis or scarring that will be a source for long-term epilepsy.These patients often require long-term antiepileptic drugtherapy.


Pediatrics_Nelson

Pediatrics_Nelson. Transient neurologic disturbances may develop a few minutes after head trauma and last for minutes to hours before clearing. The most common symptoms are corticalblindness and confusional states, but hemiparesis, ataxia, orany other neurologic deficit may appear. These symptomsmay represent a trauma-triggered migraine in susceptiblechildren, but care must be exercised to exclude intracranial pathology. Drowsiness, headache, and vomiting are common after head trauma. They are not, by themselves, of concern if consciousness is preserved, the clinical trend is one of improvement, and results of the neurologic examination are normal. Children are especially susceptible to somnolence after head trauma but should be easily arousable. If symptoms worsen or persist for more than 1 to 2 days, neuroimaging may be indicated to look for subdural hematoma or cerebral edema.


Pediatrics_Nelson

Pediatrics_Nelson. Children who have been unconscious or have amnesia following a head injury should be evaluated in an emergency department. High-risk patients include those with persistent depressed or decreasing level of consciousness, focal neurologic signs, penetrating skull injury, depressed skull fractures, or worsening symptoms. Because patients with intracranial hemorrhage may progressively deteriorate and require immediate neurosurgical care, these patients warrant care in a skilled trauma center. The Glasgow Coma Scale is a valuable tool for monitoring the course of patients after trauma for signs of deterioration (Chapter 42). Management includes ensuring an appropriate airway, breathing, and circulation. Neuroimaging with CT or magnetic resonance imaging (MRI), and skull and cervical spine radiographs are obtained emergently. Neuroimaging is not necessary for uncomplicated concussions but should be employed whenever suspicion of structural intracranial lesion exists.