Pediatrics_Nelson

Pediatrics_Nelson. Figure 134-1 Schematic representation of the respiratory control system. The respiratory neurons in the brainstem receive information from the chemoreceptors, peripheral sensory receptors, and cerebral cortex. This information is integrated, and the resulting neural output is transmitted to the diaphragms and lungs. The sign denotes stimulation of the receptor. (From Andreoli TE, Bennett JC, Carpenter CJ, et al, editors: Cecil Essentials of Medicine, ed 4, Philadelphia, 1997, WB Saunders, p 171.) apnea, color change (usually blue or pale), sudden limpness, choking, or gagging. The incidence of such events is 0.05% to 1%. Specific causes can be identified in more than 50% of the cases. Gastroesophageal reflux and laryngospasm are the most common causes of ALTE, and they are associated with emesis, choking, or gagging. Central nervous system (CNS) causes (e.g., seizures, breath-holding spells, intracranial bleeding from accidental or nonaccidental trauma) account for approximately 15%


Pediatrics_Nelson

Pediatrics_Nelson. emesis, choking, or gagging. Central nervous system (CNS) causes (e.g., seizures, breath-holding spells, intracranial bleeding from accidental or nonaccidental trauma) account for approximately 15% of cases, and cardiovascular events and metabolic derangements account for smaller percentages. Acute infection with respiratory viruses (respiratory syncytial virus [RSV] and others), pertussis, and serious bacterial infections (sepsis, meningitis) can also cause apnea in infants.


Pediatrics_Nelson

Pediatrics_Nelson. In most cases, a careful history can lead to a correct diagnosis. Questions should include history of premature birth, prior apnea, level of consciousness at the time of the event, presence or absence of respiratory effort, limpness or stiffness, jerking movements (seizure), feeding history, intercurrent illnesses, any trauma, and the social situation of the family. The physical examination should focus on bruising and injury, the general and neurologic condition of the infant, nutritional status, respiratory pattern, and cardiac status. The laboratory evaluation may include serum electrolytes, serum glucose, blood urea nitrogen, creatinine, hemoglobin, hematocrit, white blood cell count, a chest radiograph, and blood gas analysis. Testing for respiratory viruses and pertussis in patients with evidence of respiratory infection should occur. If gastroesophageal reflux is suspected, a barium swallow or pH probe study may be useful. Cardiorespiratory monitoring for 12 to 24 hours in the


Pediatrics_Nelson

Pediatrics_Nelson. with evidence of respiratory infection should occur. If gastroesophageal reflux is suspected, a barium swallow or pH probe study may be useful. Cardiorespiratory monitoring for 12 to 24 hours in the hospital can provide information on respiratory and cardiac patterns and feeding difficulties (choking, gagging, emesis); provide time to get more history and assess the home situation; and alleviate parental anxiety. Useful tests to determine CNS causes include a head computed tomography (CT) scan, magnetic resonance imaging of the brain, and an electroencephalogram (EEG) (for seizures).


Pediatrics_Nelson

Pediatrics_Nelson. There are no standard recommendations for when home monitoring should be prescribed. Polysomnography is not useful in predicting which children with ALTEs are likely to progress to sudden infant death syndrome (SIDS). The key to prevention of future events is to identify the underlying cause and treat it. Teaching parents infant cardiopulmonary resuscitation (CPR) and attempting to alleviate anxiety surrounding the event are recommended.


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Pediatrics_Nelson. SIDS is defined as the unexpected death of an infant younger than 1 year of age in which the cause remains unexplained after an autopsy, death scene investigation, and review of clinical history. The risk of SIDS is higher in premature and low birth weight infants, infants of young impoverished mothers who smoke cigarettes, African American and Native American infants, and in infants whose mothers have abused drugs. The risk of SIDS is increased threeto fivefold in siblings of infants who have died of SIDS and is highest during the winter. SIDS is rare before 4 weeks or after 6 months of age and is most common between 2 and 4 months of age. The incidence of SIDS has decreased dramatically since the 1980s.


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Pediatrics_Nelson. A variety of unproven mechanisms have been proposed to explain SIDS. SIDS is associated with prone position during sleep, especially on soft bedding. The widely advocated supine sleeping position explains, in part, the decreased incidence of SIDS during the past two decades. Current theories for a predisposition to SIDS include cellular brainstem abnormalities and maturational delay related to neural or cardiorespiratory control. A portion of SIDS deaths may be due to prolongation of the Q-T interval, abnormal CNS control of respiration, and CO2 rebreathing from sleeping face down (especially in softbedding). See Table 134-1 for the differential diagnosis of SIDS. There has been a significant decline in SIDS with the backto-sleep program and avoiding soft bedding. Thus, all parents should be instructed to place their infants in the supine position unless there are medical contraindications. All soft Fulminant infection*,† Infant botulism*


Pediatrics_Nelson

Pediatrics_Nelson. Fulminant infection*,† Infant botulism* Seizure disorder† Brain tumor* Intracranial hemorrhage due to accidental or non-accidental trauma*,‡ Hypoglycemia† Medium-chain acyl-coenzyme A dehydrogenase deficiency‡ Carnitine deficiency*,‡ Gastroesophageal reflux*,‡ Midgut volvulus/shock* *Obvious or suspected at autopsy. †Relatively common. ‡Diagnostic test required. Chapter 134 u Control of Breathing 463 bedding should be avoided, and parents who share beds with their infants should be counseled on the risks. Decreasing maternal cigarette smoking, both during and after pregnancy, is recommended. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Apnea is defined as the cessation of airflow due to either lack of respiratory effort (central apnea) or upper airway obstruction (obstructive apnea). Central apnea lasting less than 10 seconds is common in healthy infants and can be present in normal children during sleep, especially after a sigh breath. Central pauses lasting longer than 15 to 20 seconds are considered abnormal. Central apnea is more common in infants, and obstructive apnea, especially during sleep, is more common in older children. Premature infants can have apnea of prematurity, which consists of recurrent apneic episodes that are often of central origin, though they can be mixed central/obstructive. Apnea of prematurity should resolve by 44 weeks postconceptional age. Older infants and children with apnea warrant thorough investigation (Table 134-2).


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Pediatrics_Nelson. Central apnea outside of infancy is a rare occurrence and may be primary or secondary. Secondary causes of central hypoventilation, which are more common, include medications impairing central respiratory drive (narcotics), increased intracranial pressure, CNS tumors, myelomeningocele and/or Arnold-Chiari malformation, and mitochondrial/metabolic disorders. Genetic syndromes associated with abnormal central respiratory control and developmental delays include Rett, Joubert, and Prader-Willi syndromes and tuberous sclerosis.


Pediatrics_Nelson

Pediatrics_Nelson. Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder in which there is profound loss of respiratory control during sleep leading to central apnea, hypercarbia, and hypoxemia. Most patients with CCHS have a defect in the PHOX2B gene, which is necessary for autonomic nervous system development. Most infants with CCHS have respiratory difficulties within the first several weeks of life, although it can also present later in childhood. CCHS is associated with an increased risk of Hirschsprung disease and neural crest tumors (neuroblastoma).


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Pediatrics_Nelson. Obstructive sleep apnea syndrome (OSA), which affects 2% to 3% of young children with peak prevalence at 2 to 8 years, is caused by complete or partial upper airway obstruction during sleep. It presents as episodes of respiratory pauses, gasping, and restless sleep that can result in hypoxia and hypercarbia. Children may have difficulty awakening in the morning, daytime somnolence, behavioral changes, poor school performance, and poor somatic growth as a result of poor sleep quality. Nighttime hypoxia or hypercarbia can lead to morning headaches and, in severe cases, to pulmonary hypertension and cor pulmonale. Adenotonsillar hypertrophy is the most common cause of OSA in young children, but other risk factors for OSA include obesity, craniofacial malformations (Pierre Robin sequence, trisomy 21), glossoptosis, and neuromuscular diseases. Not all children who snore have OSA, and not all children who have OSA snore. Many young children with OSA do not have the classic findings of


Pediatrics_Nelson

Pediatrics_Nelson. trisomy 21), glossoptosis, and neuromuscular diseases. Not all children who snore have OSA, and not all children who have OSA snore. Many young children with OSA do not have the classic findings of daytime somnolence and gasping respirations; restless sleep, behavioral problems, and inattention/hyperactivity are much more common. Thus, when the diagnosis is in question, it should be confirmed with a polysomnogram.


Pediatrics_Nelson

Pediatrics_Nelson. Polysomnogram (PSG) is the only definitive test for evaluation of obstructive and central sleep apnea. It involves continuous recording of EEG and electro-oculogram for sleep staging, oronasal airflow and pressure, audible snore, chest and abdominal wall excursion, leg and chin electromyogram, electrocardiogram, pulse oximetry, and capnography. The measured score from a PSG is the apnea-hypopnea index(AHI) or number of times in an hour of sleep that the child has cessation or reduction of airflow of a significant magnitude to negatively affect ventilation or sleep stage. An AHI less than 1 is the generally accepted norm for pediatric patients, although the decision to treat often hinges on the severity of daytime impairment. Measured AHI is typically worse in rapid eye movement (REM) sleep and when the child is supine, so an ideal study captures all sleep stages and positions.


Pediatrics_Nelson

Pediatrics_Nelson. Treatment of OSA starts with determining whether the child will benefit from an adenoidectomy, with or without a tonsillectomy. If surgical intervention is not indicated or fails Table 134-2 Categories of Apnea DISEASE EXAMPLE(S) MECHANISM SIGNS TREATMENT Apnea of prematurity Premature (<36 wk) Central control, upper airway obstruction Apnea, bradycardia Caffeine, HFNC, CPAP, intubation Central apnea/ CCHS, Arnold-Chiari Abnormal central control Apnea Mechanical ventilation hypoventilation malformation BiPAP, Bi-level positive airway pressure; CCHS, congenital central hypoventilation syndrome; CPAP, continuous positive airway pressure; HFNC, high flow nasal cannula.


Pediatrics_Nelson

Pediatrics_Nelson. BiPAP, Bi-level positive airway pressure; CCHS, congenital central hypoventilation syndrome; CPAP, continuous positive airway pressure; HFNC, high flow nasal cannula. to alleviate the problem, then the use of continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BiPAP) via nasal interfaces can be used to distend the upper airway during sleep. This requires a tight-fitting nasal mask, which may not be well tolerated in young children. Supplemental oxygen can blunt hypoxemia in milder cases of OSA but does not alter obstruction and sleep fragmentation. In extreme cases, especially those associated with craniofacial abnormalities or hypotonia, tracheostomy may be indicated.


Pediatrics_Nelson

Pediatrics_Nelson. Upper airway obstruction (UAO), which is defined as blockage of any part of the airway located above the thoracic inlet, ranges from nasal obstruction due to the common cold to life-threatening obstruction of the larynx orupper trachea (subglottic space). In children, nasal obstruction is usually more of a nuisance than a danger becausethe mouth can serve as an airway, but it may be a serious problem for neonates, who breathe predominantly throughtheir noses. The differential diagnosis of airway obstruction varies with patient age and can also be subdivided intosupraglottic, glottic, and subglottic causes (Tables 135-1, 135-2, and 135-3). Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com UAO is more pronounced during inspiration because the negative pressure generated collapses the upper airway, increasing resistance to airflow and leading to inspiratory noise.The respiratory noise most commonly associated with UAOis stridor, a harsh sound caused by the vibration of the airway structures. Stridor often decreases during sleep, becauseof lower inspiratory flow rates, and increases during feeding,excitement, and agitation, because of higher flow rates. Occasionally stridor may also be present on exhalation. Laryngomalacia (floppy larynx) is the most common cause ofinspiratory stridor in infants and may be aggravated by swallowing problems and gastroesophageal reflux. Hoarseness suggests vocal cord involvement. Children with UAO mayhave increased inspiratory work of breathing manifested bysuprasternal retractions.


Pediatrics_Nelson

Pediatrics_Nelson. Choanal atresia Micrognathia (Pierre Robin syndrome, Treacher Collins syndrome, DiGeorge syndrome) Macroglossia (Beckwith-Wiedemann syndrome, hypothyroidism, Pompe disease, trisomy 21, hemangioma) Pharyngeal collapse Laryngeal web, cleft, atresia Vocal cord paralysis/paresis (weak cry; unilateral or bilateral, with or without increased intracranial pressure from Arnold-Chiari malformation or other central nervous system pathology) Congenital subglottic stenosis Nasal encephalocele Laryngomalacia (most common non-infectious etiology) Viral croup (most common infectious etiology) Subglottic stenosis (congenital or acquired, e.g., after intubation) Laryngeal web or cyst Laryngeal papillomatosis Vascular rings/slings Airway hemangioma Rhinitis


Pediatrics_Nelson

Pediatrics_Nelson. Viral croup (most common etiology in children 6 mo to 4 yr of age) Spasmodic/recurrent croup Bacterial tracheitis (toxic, high fever) Foreign body (airway or esophageal) Laryngeal papillomatosis Retropharyngeal abscess Hypertrophied tonsils and adenoids Epiglottitis (infection, uncommon) Inhalation injury (burns, toxic gas, hydrocarbons) Foreign bodies Angioedema (familial history, cutaneous angioedema) Anaphylaxis (allergic history, wheezing, hypotension) Trauma (tracheal or laryngeal fracture) Peritonsillar abscess (adolescents) Mononucleosis Ludwig angina


Pediatrics_Nelson

Pediatrics_Nelson. Although radiographic evaluation of a child with stridor may not be helpful, lateral views of the neck and nasopharynx may provide information about adenoidal hypertrophyand airway swelling. On anteroposterior (AP) views of theneck taken with the head in extension, the subglottic spaceshould be symmetrical and the lateral walls of the airwayshould fall away steeply. Asymmetry suggests subglottic stenosis or a mass lesion, whereas tapering suggests subglotticedema. However, these findings may be subtle. Computedtomography (CT) scans of the upper airway can help delineate the site of the obstruction but may require sedationin younger children. Flexible nasopharyngoscopy/laryngoscopy, which can be done without sedation, is extremelyuseful in assessing airway patency, the presence of adenoidtissue, vocal cord and other airway lesions, and laryngomalacia. Bronchoscopy can be useful in assessing the subglottic space and intrathoracic large airways, but this procedurerequires sedation.


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Pediatrics_Nelson. Appearance Normal to anxious Normal Anxious Agitated; toxic Anxious; toxic Prevention None None None H. influenzae type None b conjugated vaccine Prodrome/onset Insidious or sudden Sudden Sudden Biphasic Chronic with sudden worsening Appearance Drooling Variable, usually normal Normal Drooling, trismus Normal CLINICAL/ HISTORICAL FEATURE RETROPHARYNGEAL ABSCESS FOREIGN BODY ANGIOEDEMA PERITONSILLAR ABSCESS LARYNGEAL PAPILLOMATOSIS Fever Body temperature usually >38.5°C None None Body temperature None usually >38.5°C Modified from Arnold JE: Airway obstruction in children. In Kliegman RM, Nieder ML, Super DM, editors: Practical Strategies in Pediatric Diagnosis and Therapy, Philadelphia, 1996, WB Saunders, p 126. FFP, Fresh frozen plasma; HPV, human papillomavirus; RSV, respiratory syncytial virus; URI, upper respiratory tract infection (with coryza, sneezing); WBC, white blood cell.


Pediatrics_Nelson

Pediatrics_Nelson. Table 135-3 Differentiating Supraglottic from Subglottic Causes of Airway Obstruction FEATURE SUPRAGLOTTIC OBSTRUCTION SUBGLOTTIC OBSTRUCTION Common clinical syndromes Epiglottitis, peritonsillar and retropharyngeal abscess Croup, angioedema, foreign body, tracheitis Toxic Yes No, unless tracheitis is present Facial edema No No, unless angioedema is present Adapted from Davis H, Gartner JC, Galvis AG, et al: Acute upper airway obstruction: croup and epiglottitis, Pediatr Clin North Am 28:859–880, 1981. The most common cause of chronic UAO in children is hypertrophy of the adenoids and tonsils. Adenoidal and tonsillar hyperplasia may be aggravated by recurrent infection, allergy, and inhaled irritants.


Pediatrics_Nelson

Pediatrics_Nelson. The signs of adenoidal and tonsillar hypertrophy are mouth breathing, snoring, and, in some patients, obstructive sleep apnea (see Chapter 134). The eustachian tubes enter the nasopharynx at the choanae and can be obstructed by enlarged adenoids, predisposing to recurrent or persistent otitis media. Adenoidal hypertrophy is assessed by a lateral radiograph of the nasopharynx or by flexible nasopharyngoscopy. If the adenoids or tonsils are large and thought to be significantly contributing to UAO, then the most effective treatment is removal. Because the adenoids are not a discrete organ but rather consist of lymphoid tissue, regrowth is possible, especially in preschool children. If the tonsils are large and the obstruction is severe, then removing the tonsils in addition to the adenoids may be necessary.


Pediatrics_Nelson

Pediatrics_Nelson. Choanal stenosis/atresia is a congenital problem presenting inthe neonatal period. It may be bilateral or unilateral and is relatively rare. Neonates are generally obligate nose breathers, soobstruction of nasal passages can cause significant respiratorydistress, especially when feeding. Crying bypasses the obstruction because crying infants breathe though their mouths. Inability to easily pass a small catheter through the nostrils shouldraise the suspicion of choanal atresia. The diagnosis is confirmed by CT scan and by inspecting the area directly with aflexible nasopharyngoscope. An oral airway may be useful inthe short term, but the definitive treatment is surgery. Available @ StudentConsult.com SEE CHAPTER 107. Available @ StudentConsult.com SEE CHAPTER 107. SEE CHAPTER 107. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com SEE CHAPTER 107. Available @ StudentConsult.com SEE CHAPTER 107. SEE CHAPTER 107. Available @ StudentConsult.com Laryngomalacia is due to exaggerated collapse of the glottic structures, especially the epiglottis and arytenoid cartilages, during inspiration. It may be due to decreased muscular tone of the larynx and surrounding structures or to immature cartilaginous structures. Inspiratory stridor beginning at or shortly after birth should raise the suspicion of laryngomalacia (see Table 135-1). This is the most common cause of stridor in infants. It usually does not result in significant respiratory distress, but occasionally it is severe enough to cause hypoventilation, with hypercarbia, hypoxemia, and difficulty with feeding.


Pediatrics_Nelson

Pediatrics_Nelson. The primary sign of laryngomalacia is inspiratory stridorwith little or no expiratory component. The stridor is typically loudest when the infant is feeding or active and decreases when the infant is relaxed or placed prone, or when the neck is flexed. Any condition that increases upper airway inflammation will exacerbate laryngomalacia, including viral respiratory infections, dysphagia (swallowing dysfunction), and gastroesophageal reflux. Laryngomalacia normally peaks by 3 to 5 months of age and resolves between 6 and 12 months of age. However, occasionally it can persist in otherwise normal children up until 24 months of age and even longer in children with underlying conditions, especially those with neurologic diseases affecting control of upper airway muscles (such as cerebral palsy).


Pediatrics_Nelson

Pediatrics_Nelson. In many infants with presumed laryngomalacia, the diagnosis can be tentatively established by history and physical examination. If the patient follows the typical course for laryngomalacia, then no further workup is necessary. However, to firmly establish the diagnosis, which is important in more severe or atypical cases, the patient should undergo flexible nasopharyngoscopy to assess the patency and dynamic movement (collapse) of the larynx and surrounding structures. This procedure can also identify vocal cord abnormalities and airway lesions above the vocal cords. In most cases, no therapy is required for laryngomalacia. The infant should be observed closely during times of respiratory infection for evidence of respiratory compromise. Infants with severe laryngomalacia resulting in hypoventilation, hypoxia, or growth failure may benefit from a surgical procedure (aryepiglottoplasty) or, in extreme cases, a tracheostomy to bypass the upper airway. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com Subglottic stenosis is the narrowing of the portion of the trachea immediately below the vocal cords. It may be congenital but more often is acquired. Endotracheal intubation, especially prolonged or repeated intubation required in some premature infants, can lead to inflammation and scarring of the subglottic space. Subglottic stenosis can present as stridor that is frequently biphasic (on both inspiration and expiration). However, the stridor is usually more prominent on inspiration. With increasing respiratory effort, the stridor becomes louder. Very small infants may not be able to breathe with enough force to generate a sound. Subglottic stenosis may also be associated with a barky cough similar to that noted with croup. Respiratory infections can cause subglottic edema, exacerbating the clinical manifestations of subglottic stenosis. Definitive diagnosis requires endoscopic evaluation, either by flexible or rigid bronchoscopy.


Pediatrics_Nelson

Pediatrics_Nelson. Definitive diagnosis requires endoscopic evaluation, either by flexible or rigid bronchoscopy. Mild subglottic stenosis can be managed conservatively and may improve sufficiently with airway growth alone. More severe cases require surgical intervention. Depending on the nature of the lesion, endoscopic laser treatment may be effective. Other surgical options include tracheoplasty and cricoid split procedures. A tracheostomy tube may be required to bypass the subglottic space until the airway is patent enough to allow adequate airflow.


Pediatrics_Nelson

Pediatrics_Nelson. Upper airway mass lesions are relatively uncommon. The most common laryngeal tumor in childhood is the hemangioma, which usually presents before 6 months of age. (See Chapter 194.) Subglottic lesions produce asymmetrical narrowing of the subglottic space on AP radiographs of the larynx, but definitive diagnosis requires endoscopy. If the obstruction is severe, then a tracheostomy tube may be needed until the lesion spontaneously involutes or improves with therapy. Laryngeal webs are the result of failed recanalization of the glottic airway in utero, whereas laryngeal cysts typically occur as a consequence of airway trauma (intubation). Both can produce biphasic stridor and are best identified by bronchoscopy. Foreign body should be considered in any infant or child capable of ingesting small objects who develops acute onset of stridor.


Pediatrics_Nelson

Pediatrics_Nelson. Juvenile laryngeal papillomatosis is a rare condition of benign tumors caused by human papillomavirus (HPV-6 and HPV-11) acquired at birth from maternal genital warts. Clinical manifestations usually start in infancy and include biphasic stridor and hoarse voice/cry. The lesions are most commonly located in the larynx, but they can spread distally into the trachea, large bronchi, and even to the lung parenchyma. Treatment options, which are limited and rarely curative, include laser therapy and interferon. Tracheostomy may be required to ensure an adequate airway, but should be avoided if possible as reports suggest a related seeding of the distal airways with tumor. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com Vocal cord paralysis is an important cause of laryngeal dysfunction. Paralysis may be unilateral or bilateral and is more often caused by damage to the recurrent laryngeal nerve than by a central lesion. The left recurrent laryngeal nerve passes around the aortic arch and is more susceptible to damage than the right laryngeal nerve. Peripheral nerve injury may be caused by trauma (neck traction during delivery of infants or thoracic surgical procedures) and mediastinal lesions. Central causes include Arnold-Chiari malformation (meningomyelocele), hydrocephalus, and intracranial hemorrhage. Vocal cord paralysis presents as biphasic stridor and alterations in voice and cry, including a weak cry (in infants), hoarseness, and aphonia. Children with vocal cord paralysis are at risk for aspiration, often manifested as coughing/choking with drinking and coarse airway sounds audibly and by auscultation.


Pediatrics_Nelson

Pediatrics_Nelson. Patients with traumatic injury to the recurrent laryngeal nerve often have spontaneous improvement over time, usually within 3 to 6 months. If the paralyzed vocal cord has not recovered within 1 year of the injury, then it is likely to be permanently damaged. In some cases, Gelfoam injection of a paralyzed vocal cord can reposition the cord to improve phonation and airway protection. Patients with vocal cord paralysis resulting in severe airway obstruction and aspiration may require tracheostomy tube placement. Chapter 136 u Lower Airway, Parenchymal, and Pulmonary Vascular Diseases 469 LOWER AIRWAY, PARENCHYMAL, AND PULMONARY VASCULAR DISEASES


Pediatrics_Nelson

Pediatrics_Nelson. Chapter 136 u Lower Airway, Parenchymal, and Pulmonary Vascular Diseases 469 LOWER AIRWAY, PARENCHYMAL, AND PULMONARY VASCULAR DISEASES There are many causes of lower airway diseases (Table 136-1).Lower airway diseases often result in airway obstruction. The most common lower airway disease in children is asthma, which results in diffuse bronchial obstruction from airway inflammation, constriction of bronchial smooth muscle, and excessive secretions. Virus-induced wheezing episodes are common, especially in children under 3 years of age. Wheezing that begins in the first weeks or months of life or that persists despite aggressive asthma therapy is likely not due to asthma, and further diagnostic evaluation may be warranted. Wheezing that is localized to one area of the chest suggests focal airway narrowing (foreign body aspiration or extrinsic compression by masses or lymph nodes). Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com In contrast to upper airway obstruction, obstruction below the thoracic inlet causes more wheezing on expiration than on inspiration. A wheeze is a continuous sound that is produced by vibration of airway walls and generally has a more musical quality than does stridor. Intrathoracic pressure is increased relative to atmospheric pressure during exhalation, which tends to collapse the intrathoracic airways and accentuates airway narrowing on expiration. This manifests as expiratory wheeze, prolonged expiratory phase, and increased expiratory work of breathing. In patients with chronic airway infection (e.g., cystic fibrosis), the bronchi become permanently damaged and dilated (bronchiectasis). Patients with bronchiectasis have episodes of cough, often productive of purulent sputum, and may have inspiratory crackles.


Pediatrics_Nelson

Pediatrics_Nelson. When asthma is suspected, empiric trials of therapy (bronchodilators, short courses of oral corticosteroids, long-term use of inhaled corticosteroids) are useful in arriving at a diagnosis. In children older than 6 years, pulmonary function tests (spirometry) can assess airflow obstruction and response to bronchodilators. Radiographic evaluation is not needed with each episode of wheezing, but those with significant respiratory distress, fever, history consistent with foreign body Bronchial edema Infection (e.g., bronchiolitis) Inhalation of irritant gases or particulates Increased pulmonary venous pressure Bronchial hypersecretion Infection Inhalation of irritant gases or particulates Cholinergic drugs Aspiration Foreign body Aspiration of gastric contents Hypersensitivity reactions, allergic bronchopulmonary aspergillosis (seen only in children with either asthma or cystic fibrosis) Dynamic airway collapse


Pediatrics_Nelson

Pediatrics_Nelson. Hypersensitivity reactions, allergic bronchopulmonary aspergillosis (seen only in children with either asthma or cystic fibrosis) Dynamic airway collapse Airway compression by mass or blood vessel Vascular ring/sling Anomalous innominate artery Pulmonary artery dilatation (absent pulmonary valve) Bronchial or pulmonary cysts Lymph nodes (tuberculosis, lymphoma)


Pediatrics_Nelson

Pediatrics_Nelson. Bronchial hypersecretion or failure to clear secretions Bronchitis, bronchiectasis Cystic fibrosis Primary ciliary dyskinesia aspiration, or focal auscultatory findings should have posteroanterior (PA) and lateral chest radiographs obtained. Generalized hyperinflation, indicated by flattening of the diaphragms and an increased anteroposterior (AP) chest diameter, suggests diffuse obstruction of the small airways. Hyperinflation in association with patchy densities due to atelectasis is often seen in asthma and mistaken for pneumonia. Localized hyperinflation, especially on expiratory views, suggests localized bronchial obstruction (foreign body or an anatomic anomaly). Dysphagia leading to aspiration and airway inflammation can present with persistent wheezing. This is best assessed with a videofluoroscopic swallowing study. Gastroesophageal reflux may aggravate asthma and may lead to wheezing in very young children, especially if it is associated with aspiration.


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com SEE CHAPTER 78.


Pediatrics_Nelson

Pediatrics_Nelson. Tracheomalacia is a floppy trachea due to lack of structural integrity of the tracheal wall. The tracheal cartilaginousrings normally extend through an arc of approximately320°, maintaining rigidity of the trachea during changesin intrathoracic pressure. With tracheomalacia, the cartilaginous rings may not extend as far around the circumference (leaving the membranous posterior trachea widerthan usual), may be completely absent, or may be presentbut damaged. These abnormalities can result in excessivecollapse of the trachea, most pronounced during expiration.Tracheomalacia may be congenital (tracheoesophageal fistula or bony dysplasia syndromes) or acquired (long-termmechanical ventilation). Tracheomalacia must be differentiated from extrinsic tracheal compression by masses or vascular structures. Localized tracheomalacia may persist afterthe trachea has been relieved of extrinsic compression. Viralinfections may exacerbate tracheomalacia, leading to coarseexpiratory wheezing and


Pediatrics_Nelson

Pediatrics_Nelson. structures. Localized tracheomalacia may persist afterthe trachea has been relieved of extrinsic compression. Viralinfections may exacerbate tracheomalacia, leading to coarseexpiratory wheezing and barky cough. The expiratory noisesof tracheomalacia are often mistakenly ascribed to asthmaor bronchiolitis, and the barky cough is often misdiagnosed as croup.


Pediatrics_Nelson

Pediatrics_Nelson. With tracheomalacia, the tracheal collapse may only be apparent during forced exhalation or with cough. It is commonly aggravated by respiratory infections. The airway collapse may cause recurrent coarse expiratory wheeze and a prolonged expiratory phase. Secretions may be retained behind the segment of malacia, predisposing to infection. Infants with severe tracheomalacia may completely collapse their tracheas during agitation, resulting in cyanotic episodes that resemble breath-holding spells. The voice is normal, as is inspiratory effort. In older children, the hallmark sign is a brassy, barky cough due to the vibration of the tracheal walls. This cough can be loud and persistent and is often misdiagnosed as croup.


Pediatrics_Nelson

Pediatrics_Nelson. Infants with mild to moderate tracheomalacia usually require no intervention. Tracheomalacia improves with airway growth as the lumen increases in diameter and the tracheal wall becomes more firm. The treatment of older symptomatic children is geared toward treating any precipitating cause for cough and providing supportive care. Antibiotics may be necessary to treat concurrent infection. Children, especially infants, with severe tracheomalacia may require tracheostomy tubes to administer continuous positive airway pressure (CPAP), which serves to stent open the airway. Custom-length tracheostomy tubes have been used to stent open the airway when CPAP fails. Surgically placed airway stents are problematic in children because the stents cannot grow and thus serve as a source of fixed stenosis and obstruction. SEE CHAPTER 128.


Pediatrics_Nelson

Pediatrics_Nelson. Compression of the trachea by vascular structures or masses can cause significant respiratory compromise. Tracheal compression by aberrant great vessels (aorta, innominate artery) may cause wheezing, stridor, cough, and dyspnea. The most common cause of tracheal compression is anterior compression from an anomalous innominate artery that arises more distally than normal from the aortic arch. This usually results in mild respiratory symptoms, and surgical correction is rarely necessary. Complete vascular rings, which compress the esophagus posteriorly and the trachea anteriorly, include the double aortic arch and a right aortic arch with a persistent ligamentum arteriosum (most common). Both lesions have right-sided aortic arches, which may be visible on chest radio-graph. In addition to respiratory symptoms, complete vascular rings may cause dysphagia as a result of esophageal compression. The diagnosis of vascular anomalies can often be made by a barium swallow, which identifies the


Pediatrics_Nelson

Pediatrics_Nelson. symptoms, complete vascular rings may cause dysphagia as a result of esophageal compression. The diagnosis of vascular anomalies can often be made by a barium swallow, which identifies the esophageal compression. Bronchoscopy will identify a pulsatile compression of the airway, but the diagnostic procedure of choice is a computed tomography (CT) angiogram of the chest and great vessels. Complete vascular rings almost always require surgical repair. Other causes of extrinsic tracheal compression include enlarged mediastinal lymph nodes (tuberculosis), mediastinal masses (teratoma, lymphoma, thymoma, germ cell tumors), and, rarely, cystic hygromas.


Pediatrics_Nelson

Pediatrics_Nelson. Aspiration of foreign bodies into the trachea and bronchi is relatively common. The majority of children who aspirate foreign bodies are under 4 years of age. Most deaths secondary to foreign body aspiration occur in this age group. Because the right mainstem bronchus takes off at a less acute angle than the left mainstem bronchus, foreign bodies tend to lodge in right-sided airways. Some foreign bodies, especially nuts, can Chapter 136 u Lower Airway, Parenchymal, and Pulmonary Vascular Diseases 471 also lodge more proximally in the larynx or subglottic space, totally occluding the airway. Many foreign bodies are not radiopaque, which makes them difficult to detect radiographically. The most common foreign bodies aspirated by young children are food (especially nuts) and small toys. Coins more often lodge in the esophagus than in the airways. Older children have been known to aspirate rubber balloons, which can be life-threatening. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Many children who aspirate foreign bodies have clear histories of choking, witnessed aspiration, or physical or radiographic evidence of foreign body aspiration. However, a small percentage of patients have a negative history because the aspiration went unrecognized. Physical findings observed with acute foreign body aspiration may include cough, localized wheezing, unilateral absence of breath sounds, stridor, and, rarely, bloody sputum.


Pediatrics_Nelson

Pediatrics_Nelson. Most foreign bodies are small and quickly expelled, butsome may remain in the lung for long periods of time andmay come to medical attention because of persistent cough,sputum production, or recurrent unilateral pneumonia. Foreign body aspiration should be in the differential diagnosis ofpatients with persistent wheezing unresponsive to bronchodilator therapy, persistent atelectasis, recurrent or persistentpneumonia, or chronic cough without another explanation.Foreign bodies may also lodge in the esophagus and compress the trachea, thus producing respiratory symptoms.Therefore, esophageal foreign bodies should be included inthe differential diagnosis of infants or young children withpersistent stridor or wheezing, particularly if dysphagia is present.


Pediatrics_Nelson

Pediatrics_Nelson. Radiographic studies will reveal the presence of radiopaque objects and can also identify focal air trapping, especially on expiratory views. Thus, when foreign body aspiration is suspected, expiratory or lateral decubitus chest radiographs should be ordered. In addition, fluoroscopy may be helpful, especially in children who cannot perform expiratory views. If there is strong evidence (or history) of foreign body aspiration, the patient should undergo rigid bronchoscopy. Flexible bronchoscopy can be used to locate an aspirated foreign body and may be useful when the presentation is not straightforward, but foreign body removal is best performed via rigid bronchoscopy.


Pediatrics_Nelson

Pediatrics_Nelson. The best approach to preventing foreign body aspiration is to educate parents and caregivers. Before molar teeth have erupted, infants and children should not be given nuts, uncooked carrots, or other foods that may be easily broken into small pieces and aspirated. Sound parental judgment is required to determine at what age and stage of development small objects should be accessible to children. Available @ StudentConsult.com SEE CHAPTER 109. SEE CHAPTER 61.


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com SEE CHAPTER 109. SEE CHAPTER 61. Endobronchial mass lesions are relatively uncommon in children. The most common lesion is granulation tissue, which usually results from local inflammation. Tuberculosis can cause endobronchial granulomas. Primary tumors of the lung are extremely rare in children. The most common airway malignancy is the nonsecreting carcinoid tumor. Endobronchial lesions that partially obstruct an airway present with wheezing or obstructive emphysema and occasionally with hemoptysis. If the lesion completely occludes the airway, then atelectasis may result. Radiographs and CT scans of the chest aid in making the diagnosis. Bronchoscopy is often used to confirm the diagnosis.


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Pediatrics_Nelson. Congenital lobar overdistention (formerly referred to as congenital lobar emphysema) consists of overinflation of onelobe of a lung. This overdistention may cause severe respiratory distress in the neonatal period due to compression ofsurrounding normal lung tissue, but it can also be asymptomatic and remain undiagnosed for years. Radiographically,it may be mistaken for a pneumothorax. Lobectomy may berequired if respiratory distress is severe or progressive, but ifthe patient is asymptomatic, then surgical resection may notbe indicated. Pulmonary hypoplasia, or a relative decrease in amount of alveoli, may be the result of a number of congenital insults, such as congenital diaphragmatic hernia (see Chapter 61) or unilateral congenital absence of a pulmonary artery. Alveolar growth occurs after birth predominantly up to 3 years, but has been documented up to 8 years.


Pediatrics_Nelson

Pediatrics_Nelson. Emphysema is a condition due to disruption or destruction of alveolar septa. In pediatrics, the term emphysema often refers to hyperinflation or to leakage of air into the pulmonary interstitial spaces (interstitial emphysema, which may be seen in mechanically ventilated premature infants) or the subcutaneous tissue (subcutaneous emphysema). Although emphysema is common in adults, it is rare in children. However, generalized or localized hyperinflation, which can be caused by airway obstruction from a variety of causes, is common. Emphysema is commonly observed in the disease α1-antitrypsin deficiency, but it rarely appears before the second decade of life.


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Pediatrics_Nelson. Primary ciliary dyskinesia (PCD, immotile cilia syndrome)is an inherited disorder in which ultrastructural abnormalities in the cilia result in absent or disordered movement of the cilia. This disorder affects approximately 1 in 19,000persons. There are many reported abnormalities in ciliarystructure, but the most common are due to defects in the dynein arms, ultrastructural features that provide energy viaadenosine triphosphatase (ATPase), which is necessary forciliary motility.


Pediatrics_Nelson

Pediatrics_Nelson. The classic presentation is recurrent otitis media, chronic sinusitis, and bronchiectasis. Kartagener syndrome, the triad of situs inversus, pansinusitis, and bronchiectasis, accounts for approximately 50% of cases. Males are infertile as a result of immotile sperm. Because the cilia fail to beat normally, secretions accumulate in the airways, and endobronchial infection results. Chronic infection, if untreated, leads to bronchiectasis by early adulthood. Primary ciliary dyskinesia should be suspected in patients with early-onset chronic bronchitis or bronchiectasis associated with recurrent/persistent sinusitis and/or frequent otitis media.


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Pediatrics_Nelson. PCD is confirmed by electron microscopy of respiratorycilia, obtained from scrapings/biopsy of nasal or airwayepithelium. Results may be difficult to interpret as chronic infection and inflammation may lead to ultrastructuralabnormalities in nasal cilia. The measurement of nasal nitric oxide has been used as a screening tool for PCD. Low nasalnitric oxide values (<200 parts per billion) are consistentwith PCD, whereas values greater than 400 parts per billionmake the diagnosis less likely. However, the validity of nasalnitric oxide assays as a diagnostic test for PCD has not beenfully substantiated.


Pediatrics_Nelson

Pediatrics_Nelson. Treatment is geared toward treating infections and improving clearance of respiratory secretions. High resolution chestCT scans are useful to confirm and monitor bronchiectasis. Surveillance cultures help identify organisms involved and guide antibiotic therapy. Sinus surgical procedures are often done to manage chronic sinusitis, but their benefit is questionable. Most children require placement of pressure equalization (PE) tubes for management of recurrent otitis media.Chest physiotherapy and prompt treatment of bacterialinfections are helpful, but the course of the disease tends tobe slowly progressive. Preventive antibiotics, such as thrice-weekly macrolides, may reduce the number of exacerbations per year. Available @ StudentConsult.com SEE CHAPTER 110.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary edema is the seepage of fluid into the alveolar and interstitial spaces. Capillary hydrostatic forces and interstitial osmotic pressures tend to push fluid into the airspaces, whereas plasma osmotic pressures and tissue mechanical forces tend to move fluid away from the airspaces. Under normal circumstances, the sum of these forces favors absorption, so the alveolar and interstitial spaces remain dry. Fluid entering the alveoli is normally removed by pulmonary lymphatics. Pulmonary edema forms when transcapillary fluid flux exceeds lymphatic drainage. Reduced left ventricular function leads to pulmonary venous hypertension and increased capillary hydrostatic pressure, and fluid moves into the interstitial space and alveoli. Fluid initially enters the interstitial space around the terminal bronchioles, alveoli, and arterioles (interstitial edema), causing increased lung stiffness and premature closure of bronchioles on expiration. If the process continues, fluid then enters


Pediatrics_Nelson

Pediatrics_Nelson. terminal bronchioles, alveoli, and arterioles (interstitial edema), causing increased lung stiffness and premature closure of bronchioles on expiration. If the process continues, fluid then enters the alveoli, further reducing compliance and resulting in intrapulmonary shunting (alveolar units that are perfused but not ventilated). Decreased ventilation (hypercarbia) is a late finding.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary edema is most commonly due to heart failure from left ventricular or biventricular dysfunction. Pulmonary hypertension and associated cor pulmonale (rightventricular dysfunction) do not usually cause pulmonaryedema as the increased vascular resistance is proximal tothe capillary bed. Increased capillary permeability, seen indisease states such as sepsis and acute respiratory distresssyndrome, can lead to pulmonary edema. Pulmonary edemamay also occur with excessive swings in intrathoracic pressure, as seen after tracheal foreign body aspiration or severeobstruction from hypertrophied tonsils and adenoids (postobstructive pulmonary edema). Pulmonary edema mayalso be present in conditions with decreased serum oncotic pressure (hypoalbuminemia); after administration of largevolumes of intravenous (IV) fluids, especially if there iscapillary injury; with ascent to high altitude (high altitude pulmonary edema); and after central nervous system injury (neurogenic pulmonary edema).


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Pediatrics_Nelson. Available @ StudentConsult.com Chapter 136 u Lower Airway, Parenchymal, and Pulmonary Vascular Diseases 473 The clinical manifestations of pulmonary edema are dyspnea, tachypnea, and cough (often with frothy, pink-tinged sputum). As the edema worsens, there is increased work of breathing and hypoxemia; diffuse inspiratory crackles can be heard on auscultation. Chest radiographs may reveal diffuse hazy infiltrates, classically in a perihilar pattern, but these findings may be obscured by underlying lung disease. Interstitial edema (Kerley B lines)may be seen, especially at the lung bases.


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Pediatrics_Nelson. Treatment and prognosis depend on the cause of the pulmonary edema and response to therapy. Patients should be positioned in an upright posture and given supplemental O2. Diuretic therapy and rapidly acting IV inotropic agents may be helpful in cardiogenic pulmonary edema. Continuous positive airway pressure (CPAP) or intubation with positive pressure ventilation using high positive end-expiratory pressures (PEEP) may be required. SEE CHAPTER 39.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary hypertension (PH) is classified in five groups basedon mechanism. Group 1 is pulmonary arterial hypertension(PAH) due to diseases within veins and small pulmonary muscular arteries such as persistent pulmonary hypertension of thenewborn, congenital heart disease (including those with excessive pulmonary blood flow due to left-to-right cardiac shunting), exposure to various drugs (e.g., cocaine, amphetamines),and idiopathic pulmonary arterial hypertension (previouslycalled primary pulmonary hypertension). Hereditary IPAH isalso in this group and has been linked with the bone morphogenetic receptor-2 (BMPR2) gene. Group 2 is caused by dysfunction of the left heart such as valvular disease. Group 3 issecondary to lung disease or chronic hypoxia, including upperairway obstruction resulting in obstructive sleep apnea and hypoxemia. In Group 4, PH is secondary to chronic pulmonarythromboembolism. Group 5 includes PH of unclear but multifactorial diseases, including some autoimmune


Pediatrics_Nelson

Pediatrics_Nelson. in obstructive sleep apnea and hypoxemia. In Group 4, PH is secondary to chronic pulmonarythromboembolism. Group 5 includes PH of unclear but multifactorial diseases, including some autoimmune diseases andmetabolic diseases. With prolonged PAH, irreversible changesmay occur in the intima and media of the pulmonary arterioles.


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Pediatrics_Nelson. Pulmonary arterial hypertension strains the right side of theheart, which leads to hypertrophy and dilation of the right ventricle. This may result in cor pulmonale, a condition in which right-sided heart failure leads to hepatic congestion, fluid retention, and tricuspid insufficiency. In severe cor pulmonale, theventricular septum may be displaced toward the left ventricle,hindering left ventricular function. The most common causesof cor pulmonale in children are chronic lung diseases, especially severe bronchopulmonary dysplasia and scleroderma, andsevere untreated obstructive sleep apnea (with chronic hypoxia).


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary arterial hypertension should be suspected wheneverthere is prolonged hypoxemia or hemodynamically significantleft-to-right cardiac shunting. In addition to the other physicalfindings associated with pulmonary and cardiac diseases, anaccentuated pulmonary component of the second heart soundmay be heard. Definitive diagnosis is made by cardiac catheterization, but echocardiography may confirm the presence ofright ventricular hypertrophy, ventricular dysfunction, inter-ventricular septal flattening, and tricuspid insufficiency, whichcan be used to estimate the pulmonary artery pressures.


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Pediatrics_Nelson. For those with pulmonary hypertension in groups 2 through 5, treatment should focus on the underlying condition. In all conditions of PH and PAH, the relief of hypoxemia with supplemental O2 therapy is essential. Heart failure may require treatment with diuretics and restrictions of salt and fluid intake. Vasodilator therapy (sildenafil) is helpful in some patients, and inhaled nitric oxide can be used short term. Continuous infusions of prostacyclin may be helpful both acutely and chronically and is available in inhaled, subcutaneous, and intravenous forms. Endothelium antagonists may be beneficial. Unfortunately, many patients with the idiopathic form of PAH have progressive courses, and lung or heart-lung transplantation may be the only treatment option.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary hemorrhage is a rare but potentially life-threatening condition in children. It can be due to bleeding fromthe airways (hemangiomas, bronchial vessel bleeds) or fromdiffuse capillary bleeding (alveolar hemorrhage). Alveolarhemorrhage is usually due to diffuse capillary disruption/inflammation caused by autoimmune disorders and after bonemarrow transplantation. Airway bleeding can be due to airway hemangiomas, pulmonary arteriovenous malformations(as with hereditary hemorrhagic telangiectasia), and bronchial artery collaterals, which develop in some patients withchronic lung infections, especially cystic fibrosis. Idiopathic pulmonary hemosiderosis is a rare disorder characterized byrecurrent alveolar bleeding, iron deficiency anemia, and hemosiderin-laden macrophages in the lung, which can be identifiedmicroscopically with the use of special iron-staining techniquesin bronchoalveolar lavage or lung biopsy specimens. Althoughthe term hemosiderosis is sometimes used


Pediatrics_Nelson

Pediatrics_Nelson. the lung, which can be identifiedmicroscopically with the use of special iron-staining techniquesin bronchoalveolar lavage or lung biopsy specimens. Althoughthe term hemosiderosis is sometimes used interchangeablywith pulmonary hemorrhage, it is a pathologic finding thatresults from bleeding anywhere in the lung, airway, pharynx,nasopharynx, or mouth leading to hemosiderin accumulationin the lung. Pulmonary hemorrhage is a preferable term for bleeding from an intrathoracic source.


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Available @ StudentConsult.com

Pediatrics_Nelson. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Most children with pulmonary hemorrhage present with hemoptysis. It is important to rule out extrapulmonary sources of bleeding, including hematemesis and bleeding from the nasopharynx or mouth, as these are more common than true pulmonary hemorrhage. In addition to hemoptysis, the presenting signs and symptoms of pulmonary hemorrhage include cough, wheeze, shortness of breath, pallor, fatigue, cyanosis, and fever. Episodic pulmonary hemorrhage frequently manifests as recurrent respiratory symptoms associated with pulmonary infiltrates on chest radiographs. Symptomatic airway hemorrhage may result in significant hemoptysis with few radiographic changes, whereas alveolar bleeding often causes profound respiratory symptoms, hypoxemia, diffuse infiltrates on radiographs, and minimal hemoptysis. Some patients experience a localized bubbling sensation in the chest, which may be helpful in differentiating local from diffuse sources of pulmonary bleeding. Physical examination findings may


Pediatrics_Nelson

Pediatrics_Nelson. Some patients experience a localized bubbling sensation in the chest, which may be helpful in differentiating local from diffuse sources of pulmonary bleeding. Physical examination findings may include locally or diffusely decreased breath sounds, cyanosis, and crackles on auscultation.


Pediatrics_Nelson

Pediatrics_Nelson. The differential diagnosis of pulmonary hemorrhage includes alveolar and airway bleeding. The causes of alveolar (capillary) bleeding include: idiopathic pulmonary hemosiderosis; diffuse alveolitis (capillaritis) secondary to autoimmune disease; clotting disorders; venoocclusive disease; diffuse alveolar injury; and cardiac conditions associated with elevated pulmonary venous and capillary pressures (Table 136-2).Rarely, a previously well infant will present with life-threatening acute alveolar hemorrhage. Often no cause is found, and, once the acute episode resolves, the infant returns to normal. Most of these infants never have a second bleeding episode. Hemoptysis can have cardiovascular, pulmonary, or immunologic causes (see Table 136-2).


Pediatrics_Nelson

Pediatrics_Nelson. It is important to perform a thorough upper airway examination to rule out epistaxis. Sometimes this requires nasopharyngoscopy. If extrapulmonary sources of bleeding havebeen excluded, then a chest radiograph, CT angiogram ofthe chest, bronchoscopy, echocardiogram, and evaluationfor rheumatologic/autoimmune diseases, especially Good-pasture disease, granulomatosis with polyangiitis, Henoch-Schönlein purpura, and systemic lupus erythematosus, should be considered. The management of acute episodes of pulmonary bleeding includes the administration of supplemental O2, blood transfusions, and, often with acute alveolar hemorrhages, mechanical ventilation with PEEP to tamponade the bleeding. Attempts should be made to identify the cause of the bleeding. Treatment is directed toward the underlying disorders and providing supportive care. In bronchial arterial bleeding, arteriography with vessel embolization has been shown to be successful.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary embolism is rare in children. When it occurs, it is often associated with indwelling central venous catheters, Respiratory distress syndrome Bronchogenic cyst Sequestration Pneumonia (bacterial, mycobacterial, fungal, or parasitic) Cystic fibrosis Tracheobronchitis Bronchiectasis Lung abscess Tumor (adenoma, carcinoid, hemangioma, metastasis) Foreign body retention Contusion—trauma oral contraceptives, or hypercoagulable states. In adolescents, trauma, obesity, abortion, and malignancy may lead to deep vein thromboses (DVTs) and pulmonary embolism. Because the pulmonary vascular bed is distensible, small emboli, even if multiple, may be asymptomatic unless they are infected (septic emboli) and cause pulmonary infection. Large emboli may cause acute dyspnea, pleuritic chest pain, cough, and hemoptysis. Hypoxia is common, as are nonspecific ST-segment and T-wave changes on the electrocardiogram (ECG). The P2 heart sound may be increased, and an S4 sound may be present.


Pediatrics_Nelson

Pediatrics_Nelson. Although the chest x-ray is usually normal, atelectasis or cardiomegaly may be seen. The measurement of D-dimers can be used as a screening test, but it must be interpreted in light of the probability of a pulmonary embolism. If the D-dimer is normal and the probability for embolism is low, then no further workup may be necessary. However, if the D-dimer is elevated, or if it is normal but the probability of embolism is moderate or high, then the diagnostic test of choice is a CT angiogram of the chest. Ventilation-perfusion scans may revealing defects in perfusion without matching ventilation defects, but they are difficult to perform in young children. Doppler or compression ultrasonography can be useful in assessing patients for lower extremity DVTs. For definitive diagnosis of pulmonary embolism, the gold standard is still pulmonary angiography, though with the improvement in CT angiography, angiograms are now rarely necessary. Children with pulmonary embolism without an obvious


Pediatrics_Nelson

Pediatrics_Nelson. embolism, the gold standard is still pulmonary angiography, though with the improvement in CT angiography, angiograms are now rarely necessary. Children with pulmonary embolism without an obvious cause should be evaluated for hypercoagulable states, the most common of which is factor V Leiden.


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Pediatrics_Nelson. Once a pulmonary embolism is suspected, the patient should be anticoagulated, usually with low-molecular-weight heparin. All patients should receive supplemental O2, and it is important to treat the predisposing factors. Thrombolytic therapy and surgical resection of emboli are rarely indicated. Occasionally an inferior vena caval filter needs to be placed to prevent recurrent emboli.


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Pediatrics_Nelson. Cystic fibrosis (CF) is an autosomal recessive disorder that is the most common life-limiting genetic disease in whites. In the United States, the incidence of CF is approximately 1 in 3200 whites, 1 in 15,000 African Americans, and 1 in 31,000 persons of Asian heritage. The gene for CF, located on the long arm of chromosome 7, encodes for a polypeptide, the cystic fibrosis transmembrane regulator (CFTR), a chloride channel located on the apical surface of epithelial cells. CFTR is important for the proper movement of salt and water across cell membranes and maintaining the appropriate composition of various secretions, especially in the airways, liver, and pancreas. The most common mutation is a deletion of three base pairs resulting in the absence of phenylalanine at the 508 position (ΔF508). More than 1500 mutations of the CFTR gene have been identified.


Pediatrics_Nelson

Pediatrics_Nelson. The secretory and absorptive characteristics of epithelial cells are affected by abnormal CFTR, resulting in the clinical manifestations of CF. The altered chloride ion conductance in the sweat gland results in excessively high sweat sodium and chloride levels. This is the basis of the sweat chloride test, which is still the standard diagnostic test for this disorder. It is positive (elevated sweat chloride > 60 mEq/L) in 99% of patients with CF. Abnormal airway secretions make the airway more prone to colonization with bacteria. Defects in CFTR may also reduce the function of airway defenses and promote bacterial adhesion to the airway epithelium. This all leads to chronic airway infections and eventually to bronchial damage (bronchiectasis). Available @ StudentConsult.com Neck Masses Hoarseness Hemoptysis Chest Pain Diarrhea Constipation Hepatomegaly Eosinophilia Polyuria Failure to Thrive Alkalemia Hyponatremia


Pediatrics_Nelson

Pediatrics_Nelson. CF is a chronic progressive disease that can present with protein and fat malabsorption (failure to thrive, hypoalbuminemia, steatorrhea), liver disease (cholestatic jaundice), or chronic respiratory infection (Table 137-1). Many infants currently are diagnosed based on newborn screening, which has been available in all 50 states and the District of Columbia since 2010. Older children commonly present with pulmonary manifestations such as poorly controlled asthma and chronic respiratory infections. The respiratory epithelium of patients with CF exhibits marked impermeability to chloride and an excessive reabsorption of sodium. This leads to a relative dehydration of airway secretions, which results in airway obstruction and impaired mucociliary transport. This, in turn, leads to endobronchial colonization with bacteria, especially Staphylococcus aureus and Pseudomonas aeruginosa. Chronic bronchial infection results in persistent or recurrent cough that is often productive of sputum,


Pediatrics_Nelson

Pediatrics_Nelson. colonization with bacteria, especially Staphylococcus aureus and Pseudomonas aeruginosa. Chronic bronchial infection results in persistent or recurrent cough that is often productive of sputum, especially in older children. Chronic airway infection leads to airway obstruction and bronchiectasis and, eventually, to pulmonary insufficiency and premature death. The median age of survival (years) is currently in the mid-30s. Digital clubbing is common in patients with CF, even in those without significant lung disease. Chronic sinusitis and nasal polyposis are common.


Pediatrics_Nelson

Pediatrics_Nelson. Pulmonary infections with virulent strains of Burkholderia cepacia are difficult to treat and may be associated with accelerated clinical deterioration. Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus in the CF airways. It causes airway inflammation/obstruction and aggravates CF lung disease. The treatment for ABPA is systemic corticosteroids (prednisone) and anti-fungal agents (itraconazole). Minor hemoptysis is usually due to airway infection, but major hemoptysis is often caused by bleeding from bronchial artery collateral vessels in damaged/chronically infected portions of the lung. Pneumothoraces can occur in patients with advanced lung disease. Bronchiectasis, bronchitis, bronchiolitis, pneumonia Atelectasis Hemoptysis Pneumothorax Nasal polyps Sinusitis Airway reactivity Cor pulmonale (associated with chronic hypoxemia) Respiratory failure Mucoid impaction of the bronchi Allergic bronchopulmonary aspergillosis


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Pediatrics_Nelson. Meconium ileus (infants) Meconium peritonitis (infants) Volvulus (infants) Intestinal atresia (infants) Distal intestinal obstruction syndrome (non-neonatal obstruction) Rectal prolapse Intussusception Fibrosing colonopathy (strictures) Appendicitis Pancreatitis Hepatic cirrhosis (portal hypertension: esophageal varices, hypersplenism) Neonatal obstructive jaundice Hepatic steatosis Gastroesophageal reflux Cholelithiasis Growth failure (malabsorption) Fat soluble vitamin deficiency states (vitamins A, K, E, D) Insulin deficiency, symptomatic hyperglycemia, diabetes Malignancy (rare) Infertility Delayed puberty Edema-hypoproteinemia (due to protein malabsorption) Dehydration–heat exhaustion Electrolyte disturbances (hyponatremia, hypokalemia, hypochloremia, and metabolic alkalosis) Hypertrophic osteoarthropathy–arthritis Digital clubbing


Pediatrics_Nelson

Pediatrics_Nelson. Ninety percent of patients with CF are born with exocrine pancreatic insufficiency. The inspissation of mucus and subsequent destruction of the pancreatic ducts result in the inability toexcrete pancreatic enzymes into the intestine. This leads to malabsorption of proteins, sugars (to a lesser extent), and especially fat. Fat malabsorption manifests clinically as steatorrhea (largefoul-smelling stools), deficiencies of fat-soluble vitamins (A, D,E, and K), and failure to thrive. Protein malabsorption can present early in infancy as hypoproteinemia and peripheral edema.Approximately 10% of patients with CF are born with intestinal obstruction caused by inspissated meconium (meconium ileus). In older patients, intestinal obstruction may result fromthick inspissated mucus in the intestinal lumen (distal intestinal obstruction syndrome). In adolescent or adult patients,progressive pancreatic damage can lead to enough islet celldestruction to cause insulin deficiency. This initially


Pediatrics_Nelson

Pediatrics_Nelson. lumen (distal intestinal obstruction syndrome). In adolescent or adult patients,progressive pancreatic damage can lead to enough islet celldestruction to cause insulin deficiency. This initially presentsas glucose intolerance, but true diabetes that requires insulintherapy (CF-related diabetes) may develop. The failure of thesweat ducts to conserve sodium and chloride may lead to hyponatremia and hypochloremic metabolic alkalosis, especially ininfants. Inspissation of mucus in the reproductive tract leads toreproductive dysfunction in both males and females. In males,congenital absence of the vas deferens and azoospermia arenearly universal. In females, secondary amenorrhea is oftenpresent as a result of chronic illness and reduced body weight.Fertility is also diminished by abnormal secretions in the fallopian tubes and cervix, but women with CF can conceive.


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Pediatrics_Nelson. All infants with a positive newborn screen and/or with meconium ileus should be evaluated for CF. The diagnosis of CF should be seriously considered in any infant presenting with failure to thrive, cholestatic jaundice, chronic respiratory symptoms, or electrolyte abnormalities (hyponatremia, hypochloremia, metabolic alkalosis). CF should be in the differential diagnosis of children with chronic respiratory or gastrointestinal symptoms, especially if there is digital clubbing. Any child with nasal polyps, especially those younger than 12 years, should be evaluated for CF. All siblings of patients with CF should also be evaluated.


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Pediatrics_Nelson. Readily available commercial DNA tests detect many CF mutations, but because there are more than 1500 identified mutations (and others yet to be identified), DNA analysis will not detect all cases of CF. All U.S. states have newborn screening for CF, based either on elevated immunoreactive trypsinogen (IRT) levels or DNA tests, identifying the majority of infants with CF, but there are both false-positive and false-negative results. Therefore, the diagnostic test of choice is still the sweat test. Indications for performing a sweat test are listed in Table 137-2. The following criteria should be met to establish the diagnosis of CF:The presence of one or more typical clinical features of CF (chronic pulmonary disease, characteristic gastrointestinal and nutritional abnormalities, salt loss syndromes, or 1.


Pediatrics_Nelson

Pediatrics_Nelson. Two elevated sweat chloride tests performed at an accredited CF Foundation certified laboratory (positive if the value is >60 mEq/L, borderline if 40 to 60 mEq/L, and negative if <40mEq/L, with adequate sweat collection) 2. Two mutations known to cause CF identified by DNA analysis or 3. because a sibling has CF, positive sweat chloride testing or the Recurrent wheezing/difficult to control asthma Recurrent or persistent atelectasis Hemoptysis Pseudomonas aeruginosa in the respiratory tract (if not explained by other factors, e.g., tracheostomy or prolonged intubation) Meconium ileus Neonatal intestinal obstruction (meconium plug, atresia) Steatorrhea, malabsorption Hepatic cirrhosis in childhood (including any manifestations such as esophageal varices or portal hypertension) Cholestatic jaundice in infancy Pancreatitis Rectal prolapse Fat-soluble vitamin deficiency states (A, D, E, K) Hypoproteinemia, hypoalbuminemia, peripheral edema


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Pediatrics_Nelson. Prolonged, direct-reacting neonatal jaundice MISCELLANEOUS Digital clubbing Failure to thrive Family history of cystic fibrosis (e.g., in sibling or cousin) Salty taste of skin (typically noted by parent on kissing affected child—from salt crystals formed after evaporation of sweat) Hyponatremic hypochloremic alkalosis in infants Nasal polyps Recurrent sinusitis Aspermia Absent vas deferens presence of known disease-causing DNA mutations are the only criteria required for diagnosis, as clinical symptoms may not be manifested early in life.


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Pediatrics_Nelson. Although the sweat test is both specific and sensitive for CF, it is subject to technical problems, and there are false-positiveand false-negative results (Table 137-3). Cutoff diagnostic measurements for infants less than 6 months may be lower. Other supportive tests include the measurement of bioelectrical potential differences across nasal epithelium (not widely available) and measurement of fecal elastase levels. Low fecal elastase levels indicate exocrine pancreatic insufficiency. CF genotyping done by commercial laboratories identifies approximately 95% of patients with CF, but there are mutations that are not identified by standard testing. Not all mutations in CFTR are considered disease-causing and have uncertain prognostic consequences. Some infants identified by newborn screening with borderline sweat tests and mutations of uncertain consequence are considered to have CFTR-related metabolic syndrome (CRMS). Older children that present with atypical clinical features and


Pediatrics_Nelson

Pediatrics_Nelson. with borderline sweat tests and mutations of uncertain consequence are considered to have CFTR-related metabolic syndrome (CRMS). Older children that present with atypical clinical features and borderline sweat tests may be considered non-classical CF or mild variant CF.


Pediatrics_Nelson

Pediatrics_Nelson. Identification of carriers (heterozygotes) and prenatal diagnosis of children with the ΔF508 and other common mutations is offered at most medical centers. Present testing techniques can identify more than 90% of carriers. Prenatal detection of a known CF genotype may be accomplished by amniocentesis or chorionic villus sampling.


Pediatrics_Nelson

Pediatrics_Nelson. The treatment of CF is multifactorial, but it is primarily directed toward the gastrointestinal and pulmonary complications. Presently, there is no effective single cure for cystic fibrosis. Therapies targeted at correcting the underlying CFTR defect are under investigation. Recently, a landmark medication known as small-molecule potentiators targeted to improve function of defective CFTR has been approved for a small subset of CF patients who have an abnormal gating mechanism of their CFTR protein. Management of pulmonary complications is directed toward facilitating clearance of secretions from the airways and minimizing the effects of chronic bronchial infection. Airway secretion clearance techniques (chest physiotherapy) help remove mucus from the airways, and aerosolized DNAse and 7% hypertonic saline, both delivered by nebulizer, decrease the viscosity of mucus. Antibiotic therapy is important in controlling chronic infection. Monitoring pulmonary bacterial flora via airway


Pediatrics_Nelson

Pediatrics_Nelson. 7% hypertonic saline, both delivered by nebulizer, decrease the viscosity of mucus. Antibiotic therapy is important in controlling chronic infection. Monitoring pulmonary bacterial flora via airway cultures and providing aggressive therapy with appropriate antibiotics (oral, aerosolized, and IV) help to slow the progression of lung disease. Patients often require 2to 3-week courses of high-dose intravenous antibiotics and aggressive chest physiotherapy to treat pulmonary exacerbations. Antibiotics are selected based on organisms identified by sputum culture. If patients are unable to provide sputum, then a throat culture for CF pathogens can be used to direct therapy. Common infecting organisms are Pseudomonas aeruginosa and Staphylococcus aureus.


Pediatrics_Nelson

Pediatrics_Nelson. Exocrine pancreatic insufficiency is treated with enteric-coated pancreatic enzyme capsules, which contain lipase and proteases. Patients with CF are encouraged to follow high-calorie diets, often with the addition of nutritional supplements. Even with optimal pancreatic enzyme replacement, stool losses of fat and protein may be high. Fat should not be withheld from the diet, even when significant steatorrhea exists. Rather, pancreatic enzyme doses should be titrated to optimize fat absorption, although there is a limit to the doses that should be used. Lipase dosages exceeding 2500 U/kg/meal are contraindicated because they have been associated with fibrosing colonopathy. Fat-soluble vitamins (A, D, E, and K) are recommended, preferably in a water-miscible form.


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Pediatrics_Nelson. Newborns with meconium ileus may require surgical intervention, but some can be managed with contrast (Gastrografin) enemas. Intestinal obstruction in CF patients beyond the neonatal period is often due to distal intestinal obstruction syndrome (DIOS), which may need to be treated with courses of oral laxatives (polyethylene glycol) or, in more refractory cases, with balanced intestinal lavage solutions. Pancreatic enzyme dosage adjustment, adequate hydration, and dietary fiber may help prevent recurrent episodes. Patients with CF-related diabetes are treated with insulin, primarily to improve nutrition and prevent dehydration, as ketoacidosis is rare. Although transaminase elevation is common in patients with CF, only 1% to 3% of patients have progressive cirrhosis resulting in portal hypertension. Cholestasis is treated with the bile salt ursodeoxycholic acid. Portal hypertension and esophageal varices due to cirrhosis of the liver are managed, when necessary, with portal vein


Pediatrics_Nelson

Pediatrics_Nelson. hypertension. Cholestasis is treated with the bile salt ursodeoxycholic acid. Portal hypertension and esophageal varices due to cirrhosis of the liver are managed, when necessary, with portal vein shunting procedures or liver transplantation. Patients with symptomatic sinus disease and nasal polyps may require sinus surgical procedures.


Pediatrics_Nelson

Pediatrics_Nelson. The management of CF is complex and is best coordinated by personnel at accredited CF centers. As with other severe chronic diseases, management of CF patients requires a multidisciplinary team working with patients and their families to maintain an optimistic, comprehensive, and aggressive approach to treatment. Thoracic scoliosis, when it is severe (curve >60°), can be associated with chest wall deformity and limitation of chest wall movement. This, in turn, can lead to decreased lung volumes (restrictive lung disease), ventilation/perfusion mismatching, hypoventilation, and even respiratory failure (see Chapter 202).Surgical correction of scoliosis may prevent further loss oflung function, but it rarely improves pulmonary function above presurgical levels.


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Pediatrics_Nelson. Sternal concavity (pectus excavatum), a common chest wall deformity in children, is usually not associated with significant pulmonary compromise. However, occasionally, if severe, it may result in restrictive lung disease, obstructive defects, and/or decreased cardiac function. Often it comes to medical attention because of concerns over the appearance of the chest. Adolescents with pectus excavatum may complain of exercise intolerance. Routine spirometry is often normal but may show decreased vital capacity consistent with restrictive lung disease. The main reason for surgical correction is generally to improve appearance (cosmetic reasons), although in some cases surgical repair is justified to improve cardiac function and exercise tolerance.


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Pediatrics_Nelson. Pectus carinatum is an abnormality of chest wall shape in which the sternum bows out. It is not associated with abnormal pulmonary function. Underlying pulmonary disease may contribute to the deformity. It can be observed after cardiac surgery performed via midsternal approach. Surgical correction of this condition is rarely indicated, but occasionally is done for cosmetic purposes. Pneumothorax, which is the accumulation of air in the pleural space, may result from external trauma or from leakage of air from the lungs or airways. Spontaneous primary pneumothorax (no underlying cause) occurs in teenagers and young adults, more commonly in tall, thin males and smokers. Factors predisposing to secondary pneumothorax (underlying cause identified) include barotrauma from mechanical ventilation, asthma, cystic fibrosis, trauma to the chest, and severe necrotizing pneumonia. Available @ StudentConsult.com


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Pediatrics_Nelson. The most common signs and symptoms of pneumothorax are chest and shoulder pain and dyspnea. If the pneumothorax is large and compresses functional lung (tension pneumothorax), severe respiratory distress and cyanosis may be present. Subcutaneous emphysema may result when the air leak communicates with the mediastinum. Physical findings associated with pneumothorax include decreased breath sounds on the affected side, a tympanitic percussion note, and evidence of mediastinal shift (deviation of the point of maximal impact [PMI] and trachea away from the side of the pneumothorax). If the pneumothorax is small, there may be few or no clinical findings. However, the patient’s clinical condition can deteriorate rapidly if the pneumothorax expands, especially if the air in the pleural space is under pressure (tension pneumothorax). This is a life-threatening condition that can result in death if the pleural space is not decompressed by evacuation of the pleural air.


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Pediatrics_Nelson. The presence of a pneumothorax can usually be confirmed by upright chest radiographs. Computed tomography (CT) scans of the chest are useful in quantifying the size of pneumothoraces and differentiating air within the lung parenchyma (cystic lung disease) from air in the pleural space and for identifying subpleural blebs that may be present in spontaneous recurrent pneumothoraces. In infants, transillumination of the chest wall may be of some use in making a rapid diagnosis of pneumothorax.


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Pediatrics_Nelson. The type of intervention depends on the size of the pneumothorax and the nature of the underlying disease. Small pneumothoraces (<20% of thorax occupied with pleural air) may notrequire intervention as they often resolve spontaneously. Inhaling high concentrations of supplemental O2 may enhance reabsorption of pleural air by washing out nitrogen from the blood.Larger pneumothoraces and any tension pneumothorax requireimmediate drainage of the air, preferably via chest tube. In anemergency situation, a simple needle aspiration may suffice,although placement of a chest tube is often required for resolution. In patients with recurrent or persistent pneumothoraces,sclerosing the pleural surfaces to obliterate the pleural space(pleurodesis) may be necessary. This can be done either chemically, by instilling talc or sclerosis agents (doxycycline) throughthe chest tube, or mechanically, by surgical abradement. Surgical approaches, open thoracotomy and video-assisted thoracoscopic surgery


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Pediatrics_Nelson. by instilling talc or sclerosis agents (doxycycline) throughthe chest tube, or mechanically, by surgical abradement. Surgical approaches, open thoracotomy and video-assisted thoracoscopic surgery (VATS), enable visualization of the pleural spaceand resection of pleural blebs, when indicated.


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Pediatrics_Nelson. Pneumomediastinum results from the dissection of air from the pulmonary parenchyma into the mediastinum. It is usually a mild, self-limited process that does not require aggressive intervention. The most common causes in children are severe forceful coughing and acute asthma exacerbations. Common symptoms are chest pain and dyspnea. There are often no physical findings, although a crunching noise over the sternum can sometimes be appreciated on auscultation, and subcutaneous emphysema may be detected about the neck. The diagnosis is confirmed by chest radiograph, and treatment is directed toward the underlying lung disease.


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Pediatrics_Nelson. Fluid accumulates in the pleural space when the local hydrostatic forces that are pushing fluid out of the vascular space exceed the oncotic forces that are drawing fluid back into thevascular space. Pleural effusions can be transudates (intactmembrane but abnormal hydrostatic or oncotic forces)or exudates (decreased integrity of the membrane due toinflammatory processes or impaired lymphatic drainage).There are relatively few causes of transudates, the primaryones being congestive heart failure and hypoproteinemiastates, whereas the causes of exudates are legion. Almost anypulmonary inflammatory process can result in pleural fluidaccumulation. Among the most common causes of exudatesare infection (tuberculosis, bacterial pneumonia), collagen vascular diseases (systemic lupus erythematosus), andmalignancy. Chylous pleural effusions (elevated triglyceridelevels) are seen with thoracic duct injury and abnormalitiesof lymphatic drainage (lymphangiomyomatosis, lymphangiectasia). Bacterial


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Pediatrics_Nelson. andmalignancy. Chylous pleural effusions (elevated triglyceridelevels) are seen with thoracic duct injury and abnormalitiesof lymphatic drainage (lymphangiomyomatosis, lymphangiectasia). Bacterial pneumonia can lead to an accumulation ofpleural fluid (parapneumonic effusion). When this fluid is purulent or infected, then it is called an empyema, although often the terms parapneumonic effusion and empyema areused interchangeably. Parapneumonic effusion/empyemais the most common effusion in children. Most parapneumonic effusions are due to pneumonia caused by Streptococcus pneumoniae, group A streptococci, or Staphylococcus aureus.


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Pediatrics_Nelson. Available @ StudentConsult.com Small pleural effusions may be asymptomatic, but if they are large enough to compress lung tissue, then they can cause dyspnea, tachypnea, and occasionally chest pain. Effusions due to infection are usually associated with fever, malaise, poor appetite, pleuritic chest pain, and splinting. Physical findings include tachypnea, decreased breath sounds, dullness to percussion, and decreased tactile fremitus. Large effusions may occupy more than half the hemithorax and cause a mediastinal shift away from the affected side, compromising respiratory status, particularly in young children.


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Pediatrics_Nelson. The presence of pleural fluid can often be confirmed by chest radiograph. In addition to anteroposterior and lateral projections, a decubitus view should be done to assess for layering of fluid. Chest ultrasonography is useful for confirming the presence of the effusion and quantifying its size. CT scans of the chest can help differentiate pleural fluid from parenchymal lesions and pleural masses. Both ultrasonography and CT scans can determine whether parapneumonic effusions contain loculations (fibrous strands that compartmentalize the effusion). The analysis of pleural fluid is useful in differentiating a transudate from an exudate. Routine tests on pleural fluid such as cell count, pH, protein, lactose dehydrogenase, and glucose characterize the effusions. Triglyceride levels, cytology, hematocrit, gram and acid fast bacilli stain, culture, and adenosine deaminase levels can be useful in diagnosing


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Pediatrics_Nelson. Pleural fluid protein/serum protein ratio greater than 0.5 OR Pleural fluid LDH/serum LDH ratio greater than 0.6 OR Pleural fluid LDH greater than two-thirds the upper limits of Positive acid fast bacilli stain, culture Pleural fluid protein greater than 4 g/dL Pleural fluid adenosine deaminase level greater than 35-50 U/L Pleural fluid glucose 30-50 mg/dL Pleural fluid hematocrit/serum hematocrit greater than 0.5 LDH, Lactate dehydrogenase.


Pediatrics_Nelson

Pediatrics_Nelson. Pleural fluid hematocrit/serum hematocrit greater than 0.5 LDH, Lactate dehydrogenase. chylous, malignant, and tuberculous effusions (Table 138-1).However, the yield of pleural fluid cultures is low. Transudative pleural effusions have a low specific gravity (<1.015) and protein content (<2.5 g/dL), low lactate dehydrogenase activity (<200 IU/L), and a low white blood cell (WBC) count with few polymorphonuclear cells. In contrast, exudates are characterized by high specific gravity and high protein (>3 g/dL) and lactate dehydrogenase (>250 IU/L) levels. They may also have a low pH (<7.2); low glucose level (<40 mg/dL); and a high WBC count with many lymphocytes or polymorphonuclear leukocytes.


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Pediatrics_Nelson. Therapy is directed at the underlying condition causing the effusion and at relief of the mechanical consequences of the fluid collection. For small effusions, especially if they are transudates, no pleural drainage is required. Large effusions that are causing respiratory compromise should be drained. Transudates and most exudates other than parapneumonic effusions can be drained with a chest tube. With parapneumonic effusions/empyema, a chest tube alone is often not sufficient because the fluid may be thick and loculated. In such cases, pleural drainage is best achieved with either the administration of fibrinolytic agents via chest tubes or video-assisted thoracoscopic surgery (VATS). Both fibrinolytic therapy via chest tubes and VATS can reduce morbidity and length of hospital stay, but many patients with small to moderate-sized parapneumonic effusions can be managed conservatively with intravenous antibiotics alone.


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Pediatrics_Nelson. Levitzky MG: Pulmonary Physiology, ed 7, New York, 2007, McGraw-Hill Kliegman RM, Stanton BF, St. Geme JW, et al: Nelson Textbook of Pediatrics, ed 19, Philadelphia, 2011, Saunders Taussig LN, Landau LI, et al: Pediatric Respiratory Medicine, ed 2, Philadel phia, 2008, Mosby Wilmott RW, Boat TF, Bush A, et al: Kendig and Chernick’s Disorders of the Respiratory Tract in Children, ed 8, Philadelphia, 2012, Saunders The Cardiovascular System Daniel S. Schneider 19 A maternal history of medication, drug, or alcohol use or excessive smoking may contribute to cardiac and other systemic findings. The prenatal history may reveal a maternal infection early in pregnancy (possibly teratogenic) or later in pregnancy (causing myocarditis or myocardial dysfunction in infants). Infants with heart failure exhibit poor growth, with weight being more significantly affected than height and head circumference.


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Pediatrics_Nelson. Heart failure may present with fatigue or diaphoresis with feeds or fussiness. Tachypnea without significant dyspnea may be present. Older children with heart failure may have easy fatigability, shortness of breath on exertion, and sometimes orthopnea. Not keeping up with other children during play or exercise is a sign of exercise intolerance. Heart failure may be misdiagnosed as recurrent pneumonia, bronchitis, wheezing, or asthma.


Pediatrics_Nelson

Pediatrics_Nelson. A history of a heart murmur is important, but many wellchildren have an innocent murmur at some time in their lives. Other cardiac symptoms include cyanosis, palpitations, chest pain, syncope, and near-syncope. A review ofsystems assesses for possible systemic diseases or congenitalmalformation syndromes that may cause cardiac abnormalities (Tables 139-1 and 139-2). Current and past medication use as well as history of drug use, is important. Family history should be reviewed for hereditary diseases, early atherosclerotic heart disease, congenital heart disease, suddenunexplained deaths, thrombophilia, rheumatic fever, hypertension, and hypercholesterolemia. A complete cardiovascular examination starts in the supine position and includes evaluation in sitting and standing positions when possible. Inspection is supplemented by palpation and auscultation to provide a complete examination.


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Pediatrics_Nelson. The examination starts with vital signs. The normal heart rate varies with age and activity. Newborn resting heart rates are approximately 120 beats/minute, slightly higher in infants 3 to 6 months of age and then gradually declining through adolescence to near 80 beats/minute. The range of normal for any given age is approximately 30 beats/minute above or below the average. Tachycardia may be a manifestation of anemia, dehydration, shock, heart failure, or dysrhythmia. Bradycardia can be a normal finding in patients with high vagal tone (athletes), but may be a manifestation of atrioventricular block. The respiratory rate of infants is best assessed while the infant is quiet. Respiratory rate may be increased when there is a left-to-right shunt or pulmonary venous congestion.


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Pediatrics_Nelson. Normal blood pressure also varies with age. A properly sized cuff should have a bladder width that is at least 90% and a length that is 80% to 100% of the arm circumference. Initially, blood pressure in the right arm is measured. If elevated, measurements in the left arm and legs are indicated to evaluate for possible coarctation of the aorta. The pulse pressure is determined by subtracting the diastolic pressure from the systolic pressure. It is normally below 50 mm Hg or half the systolic pressure, whichever is less. A wide pulse pressure Hunter-Hurler syndrome Valvular insufficiency, heart failure, hypertension Duchenne dystrophy Cardiomyopathy, heart failure Pompe disease Short PR interval, cardiomegaly, heart failure, arrhythmias Kawasaki disease Coronary artery aneurysm, thrombosis, myocardial infarction, myocarditis Marfan syndrome Aortic and mitral insufficiency, Systemic lupus Pericarditis, Libman-Sacks erythematosus endocarditis, congenital AV block


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Pediatrics_Nelson. Systemic lupus Pericarditis, Libman-Sacks erythematosus endocarditis, congenital AV block Lyme disease Arrhythmias, myocarditis, heart failure Graves disease Tachycardia, arrhythmias, heart failure (hyperthyroidism) Tuberous sclerosis Cardiac rhabdomyoma Neurofibromatosis Pulmonic stenosis, coarctation of aorta AV, atrioventricular. Trisomy 21 (Down syndrome) Endocardial cushion defect, VSD, ASD, PDA Trisomy 18 VSD, ASD, PDA, PS Trisomy 13 VSD, ASD, PDA, dextrocardia XO (Turner syndrome) Coarctation of aorta, aortic stenosis CHARGE association TOF, aortic arch and conotruncal (coloboma, heart, atresia anomalies* choanae, retardation, genital and ear anomalies) 22q11 (DiGeorge) syndrome Aortic arch anomalies, conotruncal anomalies* VACTERL association† VSD (vertebral, anal, cardiac, tracheoesophageal, radial, renal, limb anomalies) Marfan syndrome Dilated and dissecting aorta, aortic valve regurgitation, mitral valve prolapse


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Pediatrics_Nelson. VACTERL association† VSD (vertebral, anal, cardiac, tracheoesophageal, radial, renal, limb anomalies) Marfan syndrome Dilated and dissecting aorta, aortic valve regurgitation, mitral valve prolapse William syndrome Supravalvular aortic stenosis, peripheral pulmonary stenosis Infant of diabetic mother Hypertrophic cardiomyopathy, VSD, conotruncal anomalies Asplenia syndrome Complex cyanotic heart lesions, anomalous pulmonary venous return, dextrocardia, single ventricle, single AV valve Polysplenia syndrome Azygos continuation of inferior vena cava, pulmonary atresia, dextrocardia, single ventricle Fetal alcohol syndrome VSD, ASD Fetal hydantoin syndrome TGA, VSD, TOF ASD, Atrial septal defect; AV, atrioventricular; PDA, patent ductus arteriosus; PS, pulmonic stenosis; TGA, transposition of great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect. *Conotruncal—tetralogy of Fallot, pulmonary atresia, truncus arteriosus, transposition of great arteries.


Pediatrics_Nelson

Pediatrics_Nelson. Fallot; VSD, ventricular septal defect. *Conotruncal—tetralogy of Fallot, pulmonary atresia, truncus arteriosus, transposition of great arteries. †VACTERL association is also known as VATER association, in which the limb anomalies are not included. may be seen with aortopulmonary connections (patent ductus arteriosus [PDA], truncus arteriosus, arteriovenous malformations), aortic insufficiency, or relative intravascular volume depletion (anemia, vasodilation with fever or sepsis). A narrow pulse pressure is seen with pericardial tamponade, aortic stenosis, and heart failure.


Pediatrics_Nelson

Pediatrics_Nelson. Inspection includes general appearance, nutritional status, circulation, and respiratory effort. Many chromosomal abnormalities and syndromes associated with cardiac defects have dysmorphic features or failure to thrive (see Table 139-2).Skin color must be assessed for cyanosis and pallor. Central cyanosis (tongue, lips) is associated with arterial desaturation; isolated peripheral cyanosis (hands, feet) is associated with normal arterial saturation and increased peripheral extraction of oxygen. Perioral cyanosis is a common finding, especially in pale infants or when infants and toddlers become cold. Chronic arterial desaturation results in clubbing of the fingernails and toenails. Inspection of the chest may reveal asymmetry or a prominent left precordium suggesting chronic cardiac enlargement.


Pediatrics_Nelson

Pediatrics_Nelson. After inspection, palpation of pulses in all four extremities, the precordial activity, and the abdomen is performed. Pulses are assessed for rate, regularity, intensity, symmetry, and timing between upper and lower extremities. A good pedal pulse with normal right arm blood pressure effectively rules out coarctation of the aorta. The precordium should be assessed for apical impulse, point of maximum impulse, hyperactivity, and presence of a thrill. Abdominal palpation assesses liver and spleen size. The liver size provides an assessment of intra-vascular volume and is enlarged with systemic venous congestion. The spleen may be enlarged with infective endocarditis.


Pediatrics_Nelson

Pediatrics_Nelson. Auscultation is the most important part of the cardiovascular examination, but should supplement what already has been found by inspection and palpation. Systematic listening in a quiet room allows assessment of each portion of the cardiac cycle. In addition to heart rate and regularity, the heart sounds, clicks, and murmurs need to be timed and characterized.


Pediatrics_Nelson

Pediatrics_Nelson. S1 is associated with closure of the mitral and tricuspid valves, is usually single, and is best heard at the lower left sternal border (LLSB) or apex (Fig. 139-1). Although it can normally be split, if a split S1 is heard, the possibility of an ejection click or, much less commonly, an S4 should be considered. S2 is associated with closure of the aortic and pulmonary valves. It should normally split with inspiration and be single with exhalation. Abnormalities of splitting and intensity of the pulmonary component are associated with significant anatomic and physiologic abnormalities (Table 139-3). S3 is heard in early diastole and is related to rapid ventricular filling. It is best heard at the LLSB or apex and may be a normal sound, but a loud S3 is abnormal and heard in conditions with dilated ventricles. S4 occurs late in diastole just before S1, is best heard at the LLSB/apex, and is associated with decreased ventricular compliance. It is rare and is always abnormal.


Pediatrics_Nelson

Pediatrics_Nelson. A click implies a valvular abnormality or dilated great artery. It may be ejection or midsystolic in timing and may or may not be associated with a murmur. A midsystolic click is associated with mitral valve prolapse. Ejection clicks occur early in systole. Pulmonary ejection clicks are best heard at the left upper sternal border and vary in intensity with respiration. Aortic clicks are often louder at the apex, left midsternal border, or right upper sternal border and do not vary with respiration. Available @ StudentConsult.com Murmur evaluation should determine timing, duration, location, intensity, radiation, and frequency or pitch of the murmur. The timing determines a murmur’s significance and can be used to develop a differential diagnosis (see Fig. 139-1).


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Pediatrics_Nelson. 0 20 40 60 80 100 120Pressure (mmHg)AV valve closes Aortic valve opens S1 A2 a c Aortic pressure Ventricular pressure Atrial pressure Aortic stenosis, pulmonic stenosis, atrial septal defect Ventricular septal defect, mitral regurgitation, tricuspid stenosis Mitral valve prolapse Aortic regurgitation, pulmonic regurgitation Mitral stenosis, tricuspid stenosis Patent ductus arteriosus Systolic ejection Holosystolic Pansystolic Regurgitant Late systolic Early diastolic Mid-diastolic Continuous AV valve opens Aortic valve closes v Isovolumic contraction Figure 139-1 Timing of heart murmurs. AV, Atrioventricular. One semilunar valve (aortic atresia, pulmonary atresia, truncus arteriosus) Malposed great arteries (d-TGA, l-TGA) Severe aortic stenosis Increased flow across valve (ASD, PAPVR) Prolonged flow across valve (pulmonary stenosis) Electrical delay (right bundle branch block) Early aortic closure (severe mitral regurgitation)