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Pediatrics_Nelson. Chronic HBV infection may be treated with interferon alfa-2b or lamivudine, and HCV may be treated with interferon alfa alone or usually in combination with ribavirin. Mostly adults experience these treatment regimens. The decision to treat is based on the patient’s current age, age at HBV acquisition, development of viral mutations during therapy, and stage of viral infection. Transmission of HBV by vertical transmission or infection early in life often results in chronic HBV infection in an immune tolerant phase, in which interferon usually is not effective. A protracted or relapsing course may develop in 10% to 15% of cases of HAV in adults, lasting up to 6 months with an undulating course before eventual clinical resolution. Fulminant hepatitis with encephalopathy, gastrointestinal bleeding from esophageal varices or coagulopathy, and profound jaundice is uncommon but is associated with a high mortality rate.


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Pediatrics_Nelson. Most cases of acute viral hepatitis resolve without specific therapy, with less than 0.1% of cases progressing to fulminant hepatic necrosis. HAV and HEV cause acute infection only. HBV, HCV, and HDV may persist as chronic infection with chronic inflammation, fibrosis, and cirrhosis and the associated risk of hepatocellular carcinoma. From 5% to 10% of adults with HBV develop persistent infection, defined by persistence of HBsAg in the blood for more than 6 months, compared with 90% of children who acquire HBV by perinatal transmission. Chronic HBsAg carriers are usually HBeAg-negative and have no clinical, biochemical, or serologic evidence of active hepatitis, unless there is superinfection with HDV. Approximately 10% to 15% of HBsAg carriers eventually clear HBsAg.


Pediatrics_Nelson

Pediatrics_Nelson. Approximately 85% of persons infected with HCV remain chronically infected, which is characterized by fluctuating transaminase levels (see Fig. 113-1). There is poor correlation of symptoms with ongoing liver damage. Approximately 20% of persons with chronic infection develop cirrhosis, and approximately 25% of those develop hepatocellular carcinoma. HIV infection and ethanol use increase the risk of HCV progression. Good hygienic practices significantly reduce the risk of fecal-oral transmission of HAV. Screening blood donors for evidence of hepatitis significantly reduces the risk of blood-borne transmission. Specific postexposure measures are recommended to prevent secondary cases in susceptible persons.


Pediatrics_Nelson

Pediatrics_Nelson. HAV vaccine is recommended for routine immunization of all children beginning at 12 months and for unvaccinatedolder children in areas with targeted vaccination programs.Unvaccinated household and sexual contacts of persons withHAV should receive postexposure prophylaxis as soon as possible and within 2 weeks of the last exposure. A single doseof HAV vaccine at the age-appropriate dose is preferred forpersons 12 months to 40 years of age. Immunoglobulin (0.02mL/kg) given intramuscularly is preferred for children under12 months of age, persons over 40 years of age, and immunocompromised persons. Unvaccinated travelers to endemicregions should receive a single dose of HAV vaccine administered at any time before departure.


Pediatrics_Nelson

Pediatrics_Nelson. HBV vaccine is recommended for routine immunization of all infants beginning at birth and for all children and adolescents through 18 years of age who have not been immunized previously (see Fig. 94-1). It also is recommended as a preexposure vaccination for older children and adults at increased risk of exposure to HBV, including persons undergoing hemodialysis, recipients of clotting factor concentrates, residents and staff of institutions for developmentally disabled persons, men who have sex with men, injectable drug users, inmates of juvenile detention and other correctional facilities, and health care workers. HBV vaccine already has shown effectiveness in reducing the incidence of hepatocellular carcinoma in high-risk populations. Routine prenatal screening for HBsAg is recommended for all pregnant women in the United States. Infants born to HBsAg-positive mothers should receive HBV vaccine and hepatitis B immunoglobulin (HBIG) (0.5 mL) within 12 hours of birth, with subsequent


Pediatrics_Nelson

Pediatrics_Nelson. for all pregnant women in the United States. Infants born to HBsAg-positive mothers should receive HBV vaccine and hepatitis B immunoglobulin (HBIG) (0.5 mL) within 12 hours of birth, with subsequent vaccine doses at 1 month and 6 months of age followed by testing for HBsAg and anti-HBs at 9 to 15 months of age. Infants born to mothers whose HBsAg status is unknown should receive vaccine within 12 hours of birth. If maternal testing is positive for HBsAg, the infant should receive HBIG as soon as possible (no later than 1 week of age). The combination of HBIG and vaccination is 99% effective in preventing vertical transmission of HBV. Vaccination alone without HBIG may prevent 75% of cases of perinatal HBV transmission and approximately 95% of cases of symptomatic childhood HBV infection.


Pediatrics_Nelson

Pediatrics_Nelson. Postexposure prophylaxis of unvaccinated persons usingHBIG and vaccine is recommended following needle stick injuries with blood from an HBsAg-positive patient and forhousehold members with intimate contact, including sex partners.


Pediatrics_Nelson

Pediatrics_Nelson. Urinary tract infections (UTIs) include cystitis (infection localized to the bladder), pyelonephritis (infection of the renal parenchyma, calyces, and renal pelvis), and renal abscess, which may be intrarenal or perinephric. The urinary tract and urine are normally sterile. Escherichia coli, ascending from bowel flora, accounts for 90% of first infections and 75% of recurrent infections. Over 90% of nephritogenic E. coli possess P fimbriae that binds to uroepithelial cells and P blood group antigens. Individuals with high-level expression of P1 blood group antigen are predisposed to pyelonephritis and bacteremia, as well as recurrent UTIs. Other bacteria commonly causing infection include Klebsiella, Proteus, Enterococcus, and Pseudomonas. Staphylococcus saprophyticus is associated with UTI in some children and in sexually active adolescent girls. S. saprophyticus, Chlamydia trachomatis, and E. coli are the chief causes of the acute urethral syndrome, or postcoital urethritis, which


Pediatrics_Nelson

Pediatrics_Nelson. UTI in some children and in sexually active adolescent girls. S. saprophyticus, Chlamydia trachomatis, and E. coli are the chief causes of the acute urethral syndrome, or postcoital urethritis, which typically occur 12 to 72 hours after sexual intercourse.


Pediatrics_Nelson

Pediatrics_Nelson. Approximately 8% of girls and 2% of boys have a UTI by 11 years of age. The lifetime incidence of UTI in females is about 30% compared to only 1% in males. Approximately 75% of infants younger than 3 months of age with bacteriuria are male compared with only 10% between 3 and 8 months of age. After 12 months of age, UTI in healthy children usually is seen in girls. A short urethra predisposes girls to UTI. Uncircumcised maleinfants are at 5to 12-fold increased risk for UTI compared withcircumcised male infants. Obstruction to urine flow and urinary stasis is the major risk factor and may result from anatomicabnormalities, nephrolithiasis, renal tumor, indwelling urinarycatheter, ureteropelvic junction obstruction, megaureter, extrinsic compression, and pregnancy. Vesicoureteral reflux, whetherprimary (70% of cases) or secondary to urinary tract obstruction, predisposes to chronic infection and renal scarring. Scarring also may develop in the absence of reflux.


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Pediatrics_Nelson. Available @ StudentConsult.com The symptoms and signs of UTI vary markedly with age. Few have high positive predictive values in neonates, with failure to thrive, feeding problems, and fever as the most consistent symptoms. Direct hyperbilirubinemia may develop secondary to gram-negative endotoxin. Infants 1 month to 2 years old may present with feeding problems, failure to thrive, diarrhea, vomiting, or unexplained fever. The symptoms may masquerade as gastrointestinal illness with colic, irritability, and screaming periods. At 2 years of age, children begin to show the classic signs of UTI such as urgency, dysuria, frequency, and abdominal or back pain. The presence of UTI should be suspected in all infants and young children with unexplained fever and in patients of all ages with fever and congenital anomalies of the urinary tract.


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Pediatrics_Nelson. The diagnosis of UTI in infants and young children requires the presence of both pyuria and at least 50,000 CFU/mL of a single pathogenic organism. For older children and adolescents, >100,000 CFU/mL indicates infection. Urine samples for urinalysis should be examined promptly (within 20 minutes) or refrigerated until cultured. Urine obtained by midstream, clean-catch technique for older children and adolescents is an appropriate collection method, whereas transurethral catheterization is the appropriate method for younger children and infants in which antibiotics are being started. Perineal bags for urine collection are prone to contamination and are not recommended for urine collection for culture. If there


Pediatrics_Nelson

Pediatrics_Nelson. Urinalysis showing pyuria (leukocyturia of >10 white blood cells [WBCs]/mm3) suggests infection, but also is consistent with urethritis, vaginitis, nephrolithiasis, glomerulonephritis, and interstitial nephritis. Urinary dipstick tests that combine both the leukocyte esterase and nitrite (or positive leukocyte esterase and positive microscopy for bacteria) have sensitivity of 70% and specificity of 99% for detecting a UTI. Either test used alone has poor sensitivity.


Pediatrics_Nelson

Pediatrics_Nelson. Ultrasonography of the bladder and kidneys is recommended for infants with febrile UTIs to exclude structural abnormalities or detect hydronephrosis. Voiding cystourethrogram (VCUG) is indicated if the ultrasound is abnormal (hydronephrosis, scarring, or other findings to suggest obstruction or congenital abnormality). Vesicoureteral reflux is the most common abnormality found and is ranked from grade I (ureter only) to grade V (complete gross dilation of the ureter and obliteration of caliceal and pelvic anatomy) (see Chapter 167). A technetium-99m DMSA scan can identify acute pyelonephritis and is most useful to define renal scarring as a late effect of UTI.


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Pediatrics_Nelson. The diagnosis of a UTI is confirmed by a positive urine culture, but this does not distinguish between upper tract andlower tract infection. Localization of a UTI is importantbecause upper UTI is associated more frequently with bacteremia and with anatomic abnormalities than is uncomplicated cystitis. The clinical manifestations of UTI do notreliably distinguish the site of infection in neonates, infants,and toddlers. Fever and abdominal pain may occur with either lower or upper UTI, although high fever, costovertebral tenderness, high erythrocyte sedimentation rate, leukocytosis, and bacteremia each suggest upper tract involvement.DMSA scan is sensitive for detecting acute pyelonephritisbut not commonly used.


Pediatrics_Nelson

Pediatrics_Nelson. The manifestations of UTI overlap with signs of sepsis seen in young children and with enteritis, appendicitis, mesenteric lymphadenitis, and pneumonia in older children. Dysuria may indicate pinworm infection, hypersensitivity to soaps or detergents, vaginitis, or sexual abuse and infection. Available @ StudentConsult.com Empirical therapy should be initiated for symptomatic children and for all children with a urine culture confirming UTI. For an older child who does not appear ill but has a positive urine culture, oral antibiotic therapy should be initiated. For a child with suspected UTI who appears toxic, appears dehydrated, or is unable to retain oral fluids, initial antibiotic therapy should be administered parenterally, and hospitalization should be considered.


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Pediatrics_Nelson. is uncertainty about diagnosis of UTI in a younger child or Neonates with UTI are treated for 10 to 14 days with par-infant, urine can be collected by the most convenient method enteral antibiotics because of the higher rate of bacteremia. for urinalysis and if suggestive of infection, collect urine by Older children with UTI are treated for 7 to 14 days. Initial catheterization prior to starting antibiotics. treatment with parenteral antibiotics is determined by clinical status. Parenteral antibiotics should be continued until there is clinical improvement (typically 24 to 48 hours). Specificantibiotic therapy should be guided by the local antimicrobial susceptibility patterns and the results of the patient’surine cultures because of increasing problems related to antimicrobial resistance. Commonly used parenteral antibiotics include ceftriaxone or gentamicin. Oral regimens include acephalosporin, amoxicillin plus clavulanic acid, or trimethoprim sulfamethoxazole. Infants and


Pediatrics_Nelson

Pediatrics_Nelson. Commonly used parenteral antibiotics include ceftriaxone or gentamicin. Oral regimens include acephalosporin, amoxicillin plus clavulanic acid, or trimethoprim sulfamethoxazole. Infants and children who do notshow the expected clinical response within 2 days of startingantimicrobial therapy should be re-evaluated, have anotherurine specimen obtained for culture, and undergo imagingpromptly.


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Pediatrics_Nelson. The degree of toxicity, dehydration, and ability to retain oral intake of fluids should be assessed carefully. Restoring or maintaining adequate hydration, including correction of electrolyte abnormalities that are often associated with vomiting or poor oral intake, is important. Bacteremia occurs in 2% to 5% of episodes of pyelonephritis and is more likely in infants than in older children. Focal renal abscesses are an uncommon complication. The relapse rate of UTI is approximately 25% to 40%. Most relapses occur within 2 to 3 weeks of treatment. Parents should be counseled to follow up for evaluation for subsequent fevers to evaluate for the possibility of a recurrence of UTI. If a recurrent UTI is diagnosed, further imaging studies (VCUG) are indicated to evaluate the possibility of vesicoureteral reflux (see Chapter 167).


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Pediatrics_Nelson. Primary prevention is achieved by promoting good perinealhygiene and managing underlying risk factors for UTI, suchas chronic constipation, encopresis, and daytime and nighttime urinary incontinence. There is evidence that antibioticprophylaxis may prevent more severe symptomatic recurrentinfections, although the effect is small. The impact of secondary prophylaxis to prevent renal scarring is unknown.Acidification of the urine with cranberry juice is not recommended as the sole means of preventing UTI in children at high risk.


Pediatrics_Nelson

Pediatrics_Nelson. Vulvovaginitis, which is inflammation of the vulva or the vagina or both, is the most common gynecologic problem inchildren. Low prepubertal levels of estrogen result in thin, atrophic vaginal epithelium that is susceptible to bacterialinvasion. At puberty estrogen increases, and the pH of the vagina becomes more acidic. There are several specific causesof vulvovaginitis (Table 115-1), including sexually transmitted infections such as Trichomonas vaginalis and herpes simplex virus (see Chapter 116). Nonspecific vaginitis results from overgrowth of normal aerobic vaginal flora that is associated with poor hygiene. Bacterial vaginosis is caused by Gardnerella vaginalis, which interacts synergistically with vaginal anaerobes, including Bacteroides, Mobiluncus, and Peptostreptococcus.


Pediatrics_Nelson

Pediatrics_Nelson. Nonspecific vaginitis is the most common cause of vulvovaginitis in young girls. G. vaginalis is often present as part of the normal vaginal flora in preadolescent girls but is more common in girls who are sexually active. Candida is much less common in preadolescent girls than in women. Available @ StudentConsult.com The primary symptoms of vulvovaginitis are vaginal discharge, erythema, and pruritus. Characteristics of specific etiologies are outlined in Table 115-1. Wet mount microscopic examination, prepared by mixing vaginal secretions with normal saline solution, and culture may be used to confirm a specific diagnosis (see Table 115-1).Clue cells are vaginal epithelial cells that are covered with G. vaginalis and have a granular appearance. Vaginal cultures for G. vaginalis are not useful. Candida may be identified by saline wet mount or by culture.


Pediatrics_Nelson

Pediatrics_Nelson. G. vaginalis are not useful. Candida may be identified by saline wet mount or by culture. Noninfectious causes of vulvovaginitis include physicalagents (foreign body, sand), chemical agents (bubble bath,soap, detergent), and vulvar skin disease (atopic dermatitis, seborrhea, psoriasis). Physiologic vaginal discharge orphysiologic leukorrhea of desquamated vaginal cells andmucus occurs normally in girls soon after birth, with discharge lasting for about 1 week, and appears again at 6 to 12months before menarche. The discharge is minimal, clear,and thin without pruritus or inflammation. No treatment is necessary. The treatment of vulvovaginitis depends on the etiology (see Table 115-1). Treatment of nonspecific vaginitisfocuses on improving perineal hygiene. The recommendedtreatment for bacterial vaginosis is oral metronidazole orclindamycin. Imidazole creams and vaginal tablets andsuppositories all are effective for the treatment of acute


Pediatrics_Nelson

Pediatrics_Nelson. Physiologic vaginal discharge Minimal, clear, thin discharge No pathogenic organisms on Reassurance Nonspecific vaginitis Vaginal discharge, dysuria, Evidence of poor hygiene; no Improved hygiene, sitz baths 2−3 itching; fecal soiling of underwear pathogenic organisms on culture times/day Bacterial vaginosis Often asymptomatic; possible thin vaginal discharge with a “fishy” odor At least three of the following Metronidazole, clindamycin four criteria: (1) thin, homogeneous vaginal discharge; (2) vaginal pH ≥4.5; (3) a fishy odor of volatile amines on the addition of a drop of 10% potassium hydroxide to a drop of vaginal discharge (the whiff test); and (4) the presence of clue cells on a saline wet mount of vaginal discharge (Gardnerella vaginalis and anaerobes) Sarcoptes scabiei infection Nocturnal pruritus, pruritic Mites; ova black, dots of feces 5% permethrin (scabies) vesicles, pustules in runs (microscopic)


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Pediatrics_Nelson. Sarcoptes scabiei infection Nocturnal pruritus, pruritic Mites; ova black, dots of feces 5% permethrin (scabies) vesicles, pustules in runs (microscopic) Foreign body Foul-smelling vaginal discharge, Foreign body on physical Removal of foreign body sometimes bloody examination vulvovaginal candidiasis. Douching or vaginal irrigation is PREVENTION not beneficial and is not recommended. There are no recognized prophylactic measures for bacterial vaginosis or nonspecific vaginitis. Douching is not protective and reduces normal vaginal flora, which are protective against COMPLICATIONS AND PROGNOSIS pathogenic organisms. Complications are rare. The prognosis is excellent. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. COMPLICATIONS AND PROGNOSIS pathogenic organisms. Complications are rare. The prognosis is excellent. Available @ StudentConsult.com Adolescents have the highest rates of sexually transmitted infections (STIs). Compared with adults, sexually active adolescents are more likely to believe they will not contract an STI, more likely to come into contact with an infected sexual partner, less likely to receive health care when an STI develops, and less likely to be compliant with treatment for an STI.


Pediatrics_Nelson

Pediatrics_Nelson. Although numerous organisms cause STIs, the diseases can be grouped by the characteristic clinical presentation. Urethritis and endocervicitis (Table 116-1) are characteristic of Neisseria gonorrhoeae and C. trachomatis and are the most common STIs. Note that more than 70% of genital chlamydial infections in women are asymptomatic. Genital ulcers (Table 116-2) are characteristic of syphilis (Treponema pallidum), genital herpes simplex virus (HSV) infections, chancroid (Haemophilus ducreyi), and granuloma inguinale, also known as donovanosis (Klebsiella granulomatis). Vaginal discharge (Table 116-3) is a symptom of trichomoniasis (Trichomonas vaginalis) and is part of the spectrum of vulvovaginitis (see Chapter 115), which is not always associated with sexual activity. Human papillomavirus (HPV) causes condylomata acuminata, or genital warts (Table 116-4), and is the major risk factor for cervical, vulvar, and vaginal cancers.


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Pediatrics_Nelson. STIs are associated with significant physiologic and psychological morbidity. Early diagnosis and treatment are important Table 116-1 Features of Sexually Transmitted Infections Caused by Chlamydia trachomatis and Neisseria gonorrhoeae* FEATURE C. TRACHOMATIS N. GONORRHOEAE Incubation period 5–12 days 3–14 days Possible presentations Pharyngitis, conjunctivitis (including neonatal conjunctivitis), disseminated disease (arthritis, dermatitis, endocarditis, meningitis) Signs/symptoms of common syndromes Mucopurulent cervicitis Cervical erythema, friability, with thick creamy discharge >10 PMNs/hpf Mild cervical tenderness Gram-negative intracellular diplococci Pelvic inflammatory disease Onset of symptoms day 3–10 of menstrual cycle Adnexal tenderness, mass (95%) Nausea, vomiting (variable) Weakness, syncope, dizziness (variable)


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Pediatrics_Nelson. Pelvic inflammatory disease Onset of symptoms day 3–10 of menstrual cycle Adnexal tenderness, mass (95%) Nausea, vomiting (variable) Weakness, syncope, dizziness (variable) Diagnostic tests NAAT, culture (using Thayer-Martin selective media) NAAT hpf, High-powered field; NAAT, nucleic acid amplification test; PID, pelvic inflammatory disease; PMN, polymorphonuclear cells. *Coinfection is common, and clinical presentations have significant overlap. Table 116-2 Features of Sexually Transmitted Infections Characterized by Genital Ulcers SYPHILIS GENITAL HERPES CHANCROID GRANULOMA INGUINALE (DONOVANOSIS) Agent Treponema pallidum HSV-1, HSV-2 Haemophilus ducreyi Klebsiella granulomatis Primary lesion Papule Vesicle Papule to pustule Papule Number >1 Multiple <3 >1, may coalesce Edges Distinct Reddened, ragged Ragged, undermined Rolled, distinct Base Red, smooth Red, smooth Necrotic Beefy red, clean Secretion Serous Serous Pus, blood None


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Pediatrics_Nelson. Edges Distinct Reddened, ragged Ragged, undermined Rolled, distinct Base Red, smooth Red, smooth Necrotic Beefy red, clean Secretion Serous Serous Pus, blood None Isolation No in vitro test; rabbit Culture Aspirate of node, swab of None inoculation Treatment Early: Benzathine penicillin G Acyclovir or famciclovir or Aspirate fluctuant nodes Doxycycline or TMP-SMX (2.4 million U IM) once valacyclovir Late (>1 yr duration): Incision and drainage Benzathine penicillin G (2.4 FTA-ABS, Fluorescent treponemal antibody-absorption; HSV, herpes simplex virus; MHA-TP, microhemagglutination assay-Treponema pallidum; PCR, polymerase chain reaction; RPR, rapid plasma reagin; TMP-SMX, trimethoprim-sulfamethoxazole; VDRL, Venereal Disease Research Laboratory.


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Pediatrics_Nelson. Table 116-3 Features of Sexually Transmitted Infections Characterized by Vaginal Discharge FEATURE PHYSIOLOGIC LEUKORRHEA (NORMAL) TRICHOMONIASIS BACTERIAL VAGINOSIS (GARDNERELLA VAGINALIS-ASSOCIATED VAGINITIS) Agent Normal flora Trichomonas vaginalis G. vaginalis and anaerobes Pruritus None Mild to moderate None to mild Discharge Minimal Moderate to severe Mild to moderate Characteristics of discharge Color Clear, milky Yellow-green or grey Grey Odor with None Possible Characteristic fishy odor pH <4.5 >5.0 >4.5 Saline drop Squamous and few WBCs WBC; Motile flagellates, slightly Squamous cells studded with larger than WBCs bacteria (“clue cells”) and WBCs Treatment Reassurance Metronidazole or tinidazole Metronidazole, tinidazole, or clindamycin KOH, Potassium hydroxide; WBCs, white blood cells. Presenting complaints Genital warts are seen or felt Vulvar itching or discharge Pubic itching; live organisms may be seen; sexual partner has “crabs”


Pediatrics_Nelson

Pediatrics_Nelson. Presenting complaints Genital warts are seen or felt Vulvar itching or discharge Pubic itching; live organisms may be seen; sexual partner has “crabs” Clinical associations Cervical neoplasia, dysplasia Oral contraceptives, diabetes, — antibiotics Treatment Patient-applied therapies: Podofilox solution Intravaginal agents: butoconazole Permethrin 1% cream or gel or Imiquimod cream or clotrimazole or miconazole KOH, Potassium hydroxide. for preventing medical complications and infertility. All STIs are preventable; primary prevention of STIs should be a goal for all health care providers for adolescents. Diagnosis of an STI necessitates evaluation or treatment for concomitant STIs, notification and treatment of sexual partners, and some are reportable to state health departments.


Pediatrics_Nelson

Pediatrics_Nelson. Many infections that are not traditionally considered STIs are sexually transmissible, including those caused by human immunodeficiency virus (HIV), human T cell leukemia viruses types I and II, cytomegalovirus, Epstein-Barr virus, human herpes virus (HHV-6, HHV-7), hepatitis B virus, molluscum contagiosum virus, and Sarcoptes scabiei. The presence of any STI suggests behavior that increases risk for HIV (see Chapter 125), and HIV counseling and testing should be provided to all adolescents with STIs. Acquisition of gonorrhea, syphilis, HSV-2, and trichomoniasis in prepubertal children beyond the neonatal period indicates sexual contact and signifies the need to investigate for possible sexual abuse (see Chapter 22); diagnosis of STIs in infants can represent abuse or perinatal acquisition. The association of sexual abuse with vulvovaginitis and genital HPV infection, which may result from skin or genital HPV types, is less certain.


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Pediatrics_Nelson. Direct extension of N. gonorrhoeae, often in combination with C. trachomatis, to the endometrium, fallopian tubes, and peritoneum causes pelvic inflammatory disease (PID). PID complications include tubo-ovarian abscess, perihepatitis (Fitz-Hugh-Curtis syndrome, an inflammation of the liver capsule), and infertility. The differential diagnosis of PID includes ectopic pregnancy, septic abortion, ovarian cyst torsion or rupture, urinary tract infection, appendicitis, mesenteric lymphadenitis, and inflammatory bowel disease. Pelvic ultrasound may detect thickened adnexal structures and is the imaging study of choice to exclude other possible diagnoses. Minimum clinical criteria for diagnosis of PID are lower abdominal tenderness with uterine, adnexal, or cervical motion tenderness. Additional criteria that support the diagnosis are fever, mucopurulent cervix discharge, elevated white blood cell (WBC) count, elevated inflammatory markers, and documented infection with N. gonorrhoeae or C.


Pediatrics_Nelson

Pediatrics_Nelson. criteria that support the diagnosis are fever, mucopurulent cervix discharge, elevated white blood cell (WBC) count, elevated inflammatory markers, and documented infection with N. gonorrhoeae or C. trachomatis. Adolescents should be hospitalized for treatment if there is uncertainty about the diagnosis; pregnancy; no clinical response to oral therapy within 72 hours; inability to adhere to or tolerate oral therapy; a tubo-ovarian abscess; or severe illness with high fever, nausea, and vomiting. The recommended parenteral treatment for hospitalized patients is cefotetan or cefoxitin, plus doxycycline orally. The recommended ambulatory treatment of PID for younger persons is ceftriaxone (250 mg) in a single intramuscular (IM) dose, plus doxycycline orally for 14 days, with or without metronidazole for 14 days. Follow-up examination should be performed within 72 hours.


Pediatrics_Nelson

Pediatrics_Nelson. N. gonorrhoeae, a gram-negative coccus, is often seen microscopically as diplococci. Gonorrhea is a common STI among adolescents. The highest incidence in the United States is in 15to 24-year-old females and 20to 24-year-old males, and incidence rates differ by race. The organism causes infection at the site of acquisition, which commonly results in mucopurulent cervicitis and urethritis (see Table 116-1), but infection of the rectum and pharynx can also occur. Disseminated gonococcal infections can occur with hematogenous spread and results in petechial or pustular acral skin lesions, asymmetric arthralgia, tenosynovitis or septic arthritis, and, occasionally, endocarditis or meningitis. Perinatal transmission of maternal infection can lead to neonatal sepsis and meningitis (see Chapter 65) and ophthalmia neonatorum (see Chapter 119).


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Pediatrics_Nelson. Treatment regimens should be effective against N. gonorrhoeae and C. trachomatis because of the high frequency of coinfection. Increasing rates of resistance to fluoroquinolones limit treatment options. A single IM dose of ceftriaxone (250 mg) is recommended for uncomplicated gonococcal infections of the cervix, urethra, and rectum. Hospitalization and treatment with ceftriaxone are recommended for disseminated gonococcal infections. For all gonococcal infections, azithromycin or doxycycline also should be administered unless chlamydial infection is excluded. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Chlamydiae are obligate intracellular bacteria with a biphasic life cycle, existing as relatively inert elementary bodies in their extracellular form and as reticulate bodies when phagocytosed and replicating within a phagosome. Reticulate bodies divide by binary fission and, after 48 to 72 hours, reorganize into elementary bodies that are released from the cell. Chlamydia infects nonciliated squamocolumnar cells and the transitional epithelial cells that line the mucosa of the urethra, cervix, rectum, and conjunctiva. C. trachomatis serovars D through K cause urethritis, cervicitis, PID, inclusion conjunctivitis in newborns, and infant pneumonia. C. trachomatis serovars L1–3 cause lymphogranuloma venereum, an infrequent STI characterized by unilateral, painful inguinal lymphadenitis. C. trachomatis serovars A, B, Ba, and C produce trachoma (hyperendemic blinding), which eventually leads to blindness from extensive local scarring.


Pediatrics_Nelson

Pediatrics_Nelson. Chlamydia is the most frequently diagnosed bacterial STI in adolescents and accounts for most cases of nongonococcal urethritis and cervicitis (see Table 116-1). There is a 5:1 female-to-male ratio. Males often have dysuria and a mucopurulent discharge, although approximately 25% may be asymptomatic. Women are more often asymptomatic (approximately 70%) or may have minimal symptoms including dysuria, mild abdominal pain, or vaginal discharge. Prepubertal girls may have vaginitis. At least 30% of persons with gonococcal cervicitis, urethritis, proctitis, or epididymitis have C. trachomatis coinfection.


Pediatrics_Nelson

Pediatrics_Nelson. Chlamydia infection usually is diagnosed by the detection of bacterial nucleic acids (polymerase chain reaction [PCR] tests, using ligase chain reaction and transcription-mediated amplification) of cervical, urethral, and early morning first-voided urine specimens. Amplification tests have supplanted less sensitive culture and enzyme-linked immunosorbent assay tests. Because of false positive results, only culture should be used for medicolegal purposes to confirm C. trachomatis infection in cases of suspected sexual abuse. Treatment regimens should be effective against C. trachomatis and N. gonorrhoeae because of the high frequency of coinfection. A single oral dose of azithromycin (1 g) or doxycycline for 7 days is recommended, which can be combined with a single dose of ceftriaxone (250 mg) to treat concomitant gonorrhea infection. Available @ StudentConsult.com


Pediatrics_Nelson

Pediatrics_Nelson. Syphilis is caused by T. pallidum, a long, slender, coiled spirochete. It cannot be cultivated routinely in vitro but can be observed by dark-field microscopy. Untreated infectionprogresses through several clinical stages (see Table 116-2). Primary syphilis is manifested as a single, painless genital ulcer, or chancre, usually on the genitalia, that appears 3 to 6 weeks after inoculation. Secondary syphilis follows 6 to 8 weeks later and is manifested as fever, generalized lymphadenopathy, and a disseminated maculopapular rash that alsois present on the palms and soles. Plaquelike skin lesions,condylomata lata, and mucous membrane lesions occur and are infectious. Tertiary syphilis is a slowly progressivedisease that involves the cardiovascular, neurologic, andmusculoskeletal systems and is not seen in children. Latent syphilis is an asymptomatic infection detected by serologictesting. Early latent syphilis indicates acquisition within thepreceding year; all other cases of latent


Pediatrics_Nelson

Pediatrics_Nelson. and is not seen in children. Latent syphilis is an asymptomatic infection detected by serologictesting. Early latent syphilis indicates acquisition within thepreceding year; all other cases of latent syphilis are designated either late latent syphilis or latent syphilis of unknownduration. Infection can be passed from pregnant women and infect their infants resulting in congenital syphilis (see Chapter 66).


Pediatrics_Nelson

Pediatrics_Nelson. The diagnosis of syphilis is based on serologic testing. Nontreponemal antibody tests, the Venereal Disease Research Laboratory (VDRL) test, and the rapid plasma reagin (RPR)test are screening tests and can be quantified as titers that increase with increasing duration of infection and decrease in response to therapy. A nonquantitative VDRL test can be performed on cerebrospinal fluid but is insensitive. Rheumatic disease and other infectious diseases may cause false positive results. Confirmatory, specific treponemal antibody tests, the microhemagglutination assay-T. pallidum (MHA-TP) and fluorescent treponemal antibody-absorption (FTA-ABS) are more specific and are used to confirm the diagnosis of syphilis. These tests usually remain positive lifelong even if the infection is treated and cured. Dark-field examination of chancres, mucous membranes, or cutaneous lesions may reveal motile organisms.


Pediatrics_Nelson

Pediatrics_Nelson. The treatment of choice for all stages of syphilis is parenteral penicillin G. Primary syphilis, secondary syphilis, and early latent syphilis are treated with a single IM dose of benzathine penicillin G. Tertiary, late latent, and latent syphilis of unknown duration are treated with three doses at 1-week intervals. Neurosyphilis is treated with intravenous aqueous crystalline penicillin G for 10 to 14 days. A systemic, febrile Jarisch-Herxheimer reaction occurs in 15% to 20% of syphilitic patients treated with penicillin. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com HSV-1 and HSV-2 are large, double-stranded DNA viruses of the herpesvirus family with a linear genome contained within an icosahedral capsid. There is significant DNA homology between types 1 and 2. The virus initially infects mucosal surfaces and enters cutaneous neurons where it migrates along the axons to sensory ganglia. As viral replication occurs in the ganglia, infectious virus moves along the axon to infect and destroy epithelial cells. Infection may disseminate to other organs in immunocompromised patients. Virus latency is maintained in the ganglia where it undergoes periodic reactivation and replication triggered by undefined events. Although either virus can be found in any site, HSV-1 more commonly occurs in the central nervous system, eyes, and mouth, whereas HSV-2 more commonly involves the genitalia. Reinfection can occur with exposure to the other type or even a second strain of the same type.


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Pediatrics_Nelson. Primary genital herpes is characterized by multiple painful, grouped vesicles or ulcerative and crusted external genital lesions on an erythematous base (see Table 116-2). Infemales the cervix is also involved. Symptoms may includeregional lymphadenopathy, discharge, and dysuria. Primaryillness lasts 10 to 20 days with recurrences in 50% to 80% ofpatients. Secondary, recurrent, or reactivation eruptions are not as dramatic and are not associated with systemicsymptoms. In primary infection, viral shedding lasts 1 to2 weeks, and the entire course from vesicle and ulcer onset resolves over 16 to 20 days. In recurrent disease, virus shedding lasts for less than 7 days, and the course resolves over8 to 10 days. Many persons experience five to eight recurrences per year. Some primary and many recurrent episodesare asymptomatic.


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Pediatrics_Nelson. Viral cultures and PCR are the preferred methods of diagnosis; culture typically shows cytopathic effect in 1 to 3 days and seldom takes longer than 5 days. PCR assays have increased sensitivity over culture. Viral shedding is intermittent after primary infection, so both culture and PCR can fail to detect latent infection. Serologic testing is useful for primary infection only (to show seroconversion between acute and convalescent sera), and positive serologies persist lifelong. Titers are not helpful in guiding management of recurrences.


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Pediatrics_Nelson. Oral famciclovir and valacyclovir are effective treatments in reducing the severity and duration of symptoms in primary cases and may reduce recurrences. Once-daily suppressive therapy reduces the frequency of genital herpes recurrences by 70% to 80% among patients who have frequent recurrences (more than six recurrences per year). Local hygiene and sitz baths may relieve discomfort. The use of condoms provides some protection against sexual transmission of HSV. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Trichomoniasis is caused by the protozoan T. vaginalis and often is associated with other STIs such as gonorrhea and Chlamydia. Infection is asymptomatic in as many as 90% of men and 85% of women. Symptomatic males can have urethritis. Symptomatic females have vaginitis with thin, malodorous, frothy yellow-green discharge, vulvar irritation, and cervical “strawberry hemorrhages” (see Table 116-3). Diagnosis is based on visualization of motile, flagellated protozoans in the urine or in a saline wet mount, which has a sensitivity of only 60% to 70% among symptomatic women. Culture is the most sensitive method of diagnosis. Treatment of both sexual partners with oral metronidazole or tinidazole in a single dose is recommended. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com HPV, the cause of genital warts (condylomata acuminata), is the most common STI in the United States with the highest prevalence rates among 15to 24-year-olds. Most HPV infections are asymptomatic or subclinical. HPV types 6 and 11 cause 90% of genital warts and are nononcogenic. HPV types 16 and 18 are associated with 70% of cases of cervical cancer. HPV types 31, 33, and 35 are also oncogenic. Genital warts can occur on the squamous epithelium or mucous membranes of the genital and perineal structures of females and males (see Table 116-4). Genital warts are usually multiple, firm, gray-to-pink excrescences. Untreated genital warts may remain unchanged, increase in size or number, or resolve spontaneously. They can become tender if macerated or secondarily infected. The diagnosis usually is established by appearance without biopsy. The differential diagnosis includes condylomata lata (secondary syphilis) and tumors.


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Pediatrics_Nelson. The goal of treatment is removal of symptomatic warts to induce wart-free periods. Treatment modalities involve destruction of infected epithelium; patient-applied therapies include podofilox or imiquimod, and provider-applied therapies include cryotherapy with liquid nitrogen or cryoprobe, topical podophyllin resin, and trichloroacetic acid or bichloracetic acid. An alternative is surgical removal. Intralesional interferon and laser surgery also have been effective. Factors that may influence selection of treatment include wart number, size, anatomic sites, wart morphology, patient preference, treatment cost, convenience, adverse effects, and provider experience. Recurrences after treatment are common and are frequently asymptomatic.


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Pediatrics_Nelson. Pubic lice, or pediculosis pubis, are caused by infestation with Phthirus pubis, the pubic crab louse. The louse is predominantly sexually transmitted and lives out its life cycle on pubic hair, where it causes characteristic, intense pruritus (see Table 116-4). Diagnosis can be made clinically; lice are visible to the naked eye. Erythematous papules and egg cases (nits) are not seen before puberty. Treatment consists of education regarding personal and environmental hygiene and the application of an appropriate pediculicide, such as permethrin 1% cream or pyrethrins with piperonyl butoxide. Bedding and clothing should be decontaminated (machine washed and machine dried using the heat cycle or dry cleaned) or removed from body contact for at least 72 hours.


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Pediatrics_Nelson. Acute hematogenous osteomyelitis is the most common manifestation of osteomyelitis in children and evolves secondary to bacteremia. Subacute osteomyelitis usually follows local inoculation by penetrating trauma and is not associated with systemic symptoms, and chronic osteomyelitis results from an untreated or inadequately treated (usually subacute) osteomyelitis.


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Pediatrics_Nelson. In children beyond the newborn period and without hemoglobinopathies, bone infections occur almost exclusively in the metaphysis of long bones due to sluggish blood flow through tortuous vascular loops unique to this site. Preceding nonpenetrating trauma is often reported and may lead to local bone injury that predisposes to infection. Bone infections in children with sickle cell disease occur in the diaphyseal portion of the long bones, probably as a consequence of antecedent focal infarction. In children younger than 12 to 18 months of age, capillaries perforate the epiphyseal growth plate, permitting spread of infection across the epiphysis leading to suppurative arthritis, whereas in older children, infection is contained in the metaphysis because these vessels no longer cross the epiphyseal plate (Figs. 117-1AB).


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Pediatrics_Nelson. Staphylococcus aureus is responsible for more than 80% of acute skeletal infections. Other common causes include Group A streptococcus and Streptococcus pneumoniae. Neisseria meningitidis, Mycobacterium tuberculosis, Bartonella henselae, Actinomyces spp., and anaerobes are less common causes. Group B streptococcus and enteric gram-negatives are other major causes in neonates. Sickle cell disease and other hemoglobinopathies predispose to osteomyelitis caused by Salmonella and S. aureus. Pasteurella multocida osteomyelitis may


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Pediatrics_Nelson. Figure 117-1 A, Major structures of the bone of an infant before maturation of the epiphyseal growth plate. Note the transphyseal vessel, which connects the vascular supply of the epiphysis and metaphysis, facilitating spread of infection between these two areas. B, Major structures of the bone of a child. Joint capsule A inserts below the epiphyseal growth plate, as in the hip, elbow, ankle, and shoulder. Rupture of a metaphyseal abscess in these bones is likely to produce pyarthrosis. Joint capsule B inserts at the epiphyseal growth plate, as in other tubular bones. Rupture of a metaphyseal abscess in these bones is likely to lead to a subperiosteal abscess but seldom to an associated pyarthrosis. (From Gutman LT: Acute, subacute, and chronic osteomyelitis and pyogenic arthritis in children, Curr Probl Pediatr 15:1−72, 1985.) follow cat or dog bites. The use of polymerase chain reaction testing reveals that a significant proportion of culture negative osteomyelitis is due to


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Pediatrics_Nelson. in children, Curr Probl Pediatr 15:1−72, 1985.) follow cat or dog bites. The use of polymerase chain reaction testing reveals that a significant proportion of culture negative osteomyelitis is due to Kingella kingae. Conjugate vaccine has reduced greatly the incidence of Haemophilus influenzae type b infections.


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Pediatrics_Nelson. Subacute focal bone infections caused by Pseudomonas aeruginosa and S. aureus usually occur in ambulatory persons who sustain puncture wounds of the foot. Pseudomonas chondritis is strongly associated with puncture wounds through sneakers, which harbor Pseudomonas in the foam insole. S. aureus is the most common cause of chronic osteomyelitis. Chronic recurrent multifocal osteomyelitis is an autoinflammatory syndrome characterized by recurrent episodes of fever, bone pain, and radiographic findings of osteomyelitis. Bones uncommonly involved in acute hematogenous osteomyelitis such as the clavicle, scapula, or small bones of the hands or feet are often affected, pathogens are not identified on culture, and histopathology demonstrates plasmacytic infiltrates. Osteomyelitis may occur at any age but is most common in children 3 to 12 years of age and affects boys twice as frequently as girls. Osteomyelitis from penetrating trauma or peripheral vascular disease is more common in adults.


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Pediatrics_Nelson. Available @ StudentConsult.com Limp Knee Pain Extremity Pain Stiff or Painful Neck Fever without a Source Fever of Unknown Origin The most common presenting complaints are focal pain, exquisite point tenderness over the bone, warmth, erythema, and swelling. Fever, anorexia, irritability, and lethargy may accompany the focal findings. Weight bearing and active and passive motion of the affected extremity are decreased, mimicking paralysis (pseudoparalysis). Muscle spasm may make the extremity difficult to examine. The adjacent joint space may be involved in young children, suggested by pain with minimal joint range of motion (see Chapter 118).


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Pediatrics_Nelson. Usually only one bone is involved. The femur, tibia, or humerus is affected in approximately two thirds of patients. Approximately 15% of cases involve the bones of the hands or feet, and 10% involve the pelvis. Vertebral osteomyelitis is notable for an insidious onset, vague symptoms, backache, occasional spinal cord compression, and, usually, little associated fever or systemic toxicity. Patients with osteomyelitis of the pelvis may present with fever, limp, and vague abdominal, hip, groin, or thigh pain. Pyomyositis of pelvic muscles may mimic osteomyelitis.


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Pediatrics_Nelson. The presence of leukocytosis is inconsistent. Blood cultures are important but are negative in many cases. Elevated acute phase reactants, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are sensitive but nonspecific findings. Serial determinations of ESR and CRP are helpful in monitoring the course of the illness and response to treatment. Direct subperiosteal or metaphyseal needle aspiration definitively establishes the diagnosis. Identification of bacteria in aspirated material by Gram stain can establish the diagnosis within hours of clinical presentation.


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Pediatrics_Nelson. Plain radiographs can demonstrate soft tissue swelling such as the loss of the periosteal fat line within the first 3 days of symptoms, but bony lesions such as periosteal elevation and bone destruction are absent until after 10 to 14 days of symptoms (Fig. 117-2). Brodie abscess is a subacute intraosseous abscess that does not drain into the subperiosteal space and is classically located in the distal tibia. Sequestra, portions of


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Pediatrics_Nelson. Figure 117-2 Multifocal acute osteomyelitis in a 3-week-old infant with multiple joint swelling and generalized malaise. Frontal (A) and lateral (B) radiographs of the left knee show focal destruction of the distal femoral metaphysis with periosteal reaction and generalized soft tissue swelling. Frontal (C) and lateral (D) views of the right knee show an area of focal bone destruction at the distal femoral metaphysis with periosteal reaction and medial soft tissue swelling. Needle aspiration of multiple sites revealed Staphylococcus aureus. (From Moffett KS, Aronoff SC: Osteomyelitis. In Jenson HB, Baltimore RS, editors: Pediatric Infectious Diseases: Principles and Practice, ed 2, Philadelphia, 2002, Saunders, p 1038.) avascular bone that have separated from adjacent bone, frequently are covered with a thickened sheath, or involucrum, both of which are hallmarks of chronic osteomyelitis.


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Pediatrics_Nelson. Radionuclide scanning for osteomyelitis has largely been supplanted by magnetic resonance imaging, which is sensitive to the inflammatory marrow changes even during the earliest stages of osteomyelitis. Technetium-99m bone scans are useful for identifying multifocal disease. Gallium-67 scans are often positive if the technetium-99m bone scan is negative. Osteomyelitis must be differentiated from infectious arthritis (see Chapter 118), cellulitis, pyomyositis, fasciitis, diskitis, trauma, juvenile idiopathic arthritis, bone cysts, histiocytosis, and malignancy. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Initial antibiotic therapy for osteomyelitis is based on the likely organism for the age of the child, Gram stain of bone aspirate, and associated diseases (Table 117-1). Initial therapy includes an antibiotic that targets S. aureus and Kingella, such as oxacillin or nafcillin. Clindamycin or vancomycin should be used if methicillin-resistant S. aureus is suspected based on patient factors or local S. aureus epidemiology. For patients with sickle cell disease, initial therapy should include an antibiotic with activity against Salmonella. Kingella kingae Penicillin G, oxacillin, or cefotaxime *Optimal specific therapy is based on susceptibilities of the organism that is isolated.


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Pediatrics_Nelson. Kingella kingae Penicillin G, oxacillin, or cefotaxime *Optimal specific therapy is based on susceptibilities of the organism that is isolated. Response to intravenous (IV) antibiotics usually occurs within 48 hours. Lack of improvement after 48 hours indicates that surgical drainage may be necessary or that an unusual pathogen may be present. Surgical drainage is indicated for extensive or severe disease, if the disease is chronic or atypical, the hip joint is involved, or sequestrum or spinal cord compression is present. Antibiotics are administered for a minimum of 4 to 6 weeks. After initial inpatient treatment and adequate clinical response, including decreases in CRP or ESR, transition to home therapy with oral or IV antibiotics may be considered if adherence is ensured.


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Pediatrics_Nelson. Complications of acute osteomyelitis are uncommon and usually arise because of inadequate or delayed therapy or concomitant bacteremia. Vascular insufficiency, which affects delivery of antibiotics, and trauma are associated with higher rates of complications. Hematogenous osteomyelitis has an excellent prognosis if treated promptly and if surgical drainage is performed when appropriate. The poorest outcomes are in neonates and in infants with involvement of the hip or shoulder joints (see Chapter 118). Approximately 2% to 4% of acute infections recur despite adequate therapy, and approximately 25% of these fail to respond to extensive surgical debridement and prolonged antimicrobial therapy, ultimately resulting in bone loss, sinus tract formation, or amputation (although rare). Sequelae related to skeletal growth disturbance are most common with neonatal osteomyelitis.


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Pediatrics_Nelson. There are no effective means to prevent hematogenous S. aureus osteomyelitis. Universal immunization of infants with conjugate Haemophilus influenzae type b vaccine has practically eliminated serious bacterial infections from this organism, including bone and joint infections. Children with puncture wounds to the foot should receive prompt irrigation, cleansing, debridement, removal of any visible foreign body or debris, and tetanus prophylaxis. The value of oral prophylactic antibiotics for preventing osteomyelitis after penetrating injury is uncertain.


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Pediatrics_Nelson. Infectious arthritis (suppurative or septic arthritis) is a serious bacterial infection of the joint space resulting from hematogenous dissemination of bacteria. Infectious arthritis less often results from contiguous spread of infection from surrounding soft tissues or direct inoculation into the joint (penetrating trauma). Spread of osteomyelitis into the joint space is more common in children under 18 months of age and occurs via organisms passing through transphyseal vessels to the epiphysis (see Fig. 117-1A). The bacteria causing infectious arthritis are similar to bacteria causing osteomyelitis (Table 118-1). Lyme disease also may cause arthritis (see Chapter 122).


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Pediatrics_Nelson. The arthritis of disseminated gonococcal infectionsincludes both reactive and suppurative forms in early and late gonococcal disease, respectively. With untreated genital infection, gonococcemia may occur with fever and a polyarticular, symmetric arthritis and rash, known as the arthritis-dermatitis syndrome. Bacterial cultures of the synovium are sterile at this stage, despite a relatively high prevalence of bacteremia. Monarticular arthritis of large, weight-bearing joints develops S. aureus Anaerobic bacteria Streptococcus pneumoniae Pseudomonas aeruginosa Group A streptococci Enterobacteriaceae Kingella kingae Haemophilus influenzae type b* N. gonorrhoeae Mycobacterium tuberculosis *The incidence of invasive infections caused by H. influenzae type b has diminished greatly with universal childhood Hib vaccination. days to weeks later. Cultures of affected synovial fluid at this stage often yield the pathogen.


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Pediatrics_Nelson. days to weeks later. Cultures of affected synovial fluid at this stage often yield the pathogen. Reactive arthritis is immune-mediated synovial inflammation that follows a bacterial or viral infection, especially Yersinia and other enteric infections. Reactive arthritis of the hip joints in children 3 to 6 years of age is known as toxic or transient synovitis (see Chapter 200). Infectious arthritis occurs most commonly in children younger than 5 years of age and adolescents. Available @ StudentConsult.com The typical features of suppurative arthritis include monarticular involvement with erythema, warmth, swelling, and tenderness over the affected joint with a palpable effusion Normal Clear, yellow 0–200 (200)* <10 Good No difference — Trauma Clear, turbid, or 50–4000 (600) <30 Good No difference Common in hemorrhagic LE, Lupus erythematosus; PMN, polymorphonuclear cell; PPD, purified protein derivative of tuberculin; WBC, white blood cell. *Average in parentheses.


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Pediatrics_Nelson. LE, Lupus erythematosus; PMN, polymorphonuclear cell; PPD, purified protein derivative of tuberculin; WBC, white blood cell. *Average in parentheses. and markedly decreased range of movement. The onset may be sudden or insidious with symptoms noted when the joint is moved only, such as during a diaper change, or if parents become aware of decreased voluntary movement of a joint or limb. Toddlers may exhibit a limp or refuse to walk. In septic arthritis of the hip, the lower limb may be preferentially held in external rotation and flexion to minimize pain from pressure on the joint capsule. Similarly the knee and elbow joints usually are held in flexion. The joints of the lower extremity are most often involved: the knees (40%), the hips (20%), and the ankles (14%). Small joints, such as those of the hand, usually are involved after penetrating trauma or closed fist injuries.


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Pediatrics_Nelson. Minor genital tract symptoms that have been ignored may precede development of the early arthritis-dermatitis syndrome associated with disseminated gonococcal infection. A history of febrile illness antedating the development of monarticular arthritis characterizes late gonococcal arthritis. Reactive arthritis is typically symmetric, polyarticular, and usually involves the large joints, especially the hips. Patients may have had a preceding episode of gastroenteritis or urethritis. Urethritis may appear with the arthritis. Leukocytosis and an elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are common. Arthrocentesis is important to distinguish among the causes of arthritis (Table 118-2). Adolescents with acute infectious arthritis should have urethral, cervical, rectal, and pharyngeal examinations and cultures or nucleic acid amplification tests performed for Neisseria gonorrhoeae.


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Pediatrics_Nelson. Blood or joint cultures are positive in approximately 50% of cases. Joint fluid that exhibits the characteristics of pyogenic infection may not reveal bacterial pathogens, even in the absence of preceding antibiotic therapy, because of the bacteriostatic effects of synovial fluid. Gram stain, acid-fast stain, and potassium hydroxide preparation for fungi should be performed and are often informative even if the cultures are negative. Plain radiographs typically add little information to the physical findings. Radiographs may show swelling of the joint capsule, a widened joint space, and displacement of adjacent normal fat lines. Radionuclide scans are of limited use, although magnetic resonance imaging or technetium-99m bone scans may be helpful to exclude concurrent bone infection or deep abscesses. Ultrasound is especially useful for identifying joint effusions and is the initial diagnostic procedure of choice for evaluation of suppurative infections of the hip.


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Pediatrics_Nelson. The differential diagnosis of infectious arthritis in infants, children, and adolescents includes other infectious diseases, autoimmune disorders, rheumatic fever, and trauma. Suppurative arthritis must be distinguished from Lyme disease, osteomyelitis, suppurative bursitis, fasciitis, myositis, cellulitis, and soft tissue abscesses. Psoas muscle abscess often presents with fever and pain on hip flexion and rotation. Juvenile idiopathic arthritis, Kawasaki disease, Henoch-Schönlein purpura, other rheumatic disorders, and Crohn’s disease must be differentiated from infectious arthritis. In most of these diseases, the presence of symmetric or multiple joint involvement Infants (younger Group B Ampicillin plus than 2 months of streptococci aminoglycoside age) Staphylococcus Nafcillin (or oxacillin), aureus vancomycin Older infants and S. aureus Nafcillin (or oxacillin), children Kingella kingae Penicillin G, nafcillin (or oxacillin) or cefotaxime


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Pediatrics_Nelson. Staphylococcus Nafcillin (or oxacillin), aureus vancomycin Older infants and S. aureus Nafcillin (or oxacillin), children Kingella kingae Penicillin G, nafcillin (or oxacillin) or cefotaxime Neisseria Ceftriaxone gonorrhoeae: *The incidence of invasive infections caused by H. influenzae type b has diminished greatly with universal childhood Hib vaccination. often excludes infectious arthritis. Suppurative bursitis with Staphylococcus aureus occurs most often in older boys and men and is usually a consequence of trauma or, less commonly, a complication of bacteremia.


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Pediatrics_Nelson. Initial antibiotic therapy for infectious arthritis is based on the likely organism for the age of the child and the Gram stain of joint fluid. Suppurative arthritis of the hip joint, especially, or shoulder joint necessitates prompt surgical drainage. With insertion of the joint capsule below the epiphysis in these balland-socket joints, increased pressure in the joint space can adversely affect the vascular supply to the head of the femur or humerus, leading to avascular necrosis. Infections of the knee may be treated with repeated arthrocenteses, in addition to appropriate parenteral antibiotics.


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Pediatrics_Nelson. Several antimicrobial agents provide adequate antibiotic levels in joint spaces (Table 118-3). Initial therapy for neonates should include antibiotics with activity against S. aureus, group B streptococcus, and aerobic gram-negative rods, such as nafcillin and cefotaxime. Initial therapy for children 3 months to 5 years old should include antibiotics with activity against S. aureus. Addition of appropriate antibiotics should be considered if the child is unimmunized against Haemophilus influenzae type b (Hib). Confirmed methicillin-susceptible S. aureus infections are best treated with nafcillin or oxacillin, and methicillin-resistant S. aureus infections are best treated with clindamycin, if susceptible, or vancomycin otherwise.


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Pediatrics_Nelson. The duration of therapy depends on clinical resolution offever and pain and decline of the ESR and CRP. Infectionwith virulent organisms, such as S. aureus, usually necessitates treatment for at least 21 days. Treatment may bechanged to oral antibiotics if adherence can be ensured. Oral agents with excellent activity against S. aureus that are often used to complete therapy include cephalexin, clindamycin,amoxicillin-clavulanate, dicloxacillin, and ciprofloxacin (forpatients >18 years).


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Pediatrics_Nelson. The prognosis for the common forms of infectious arthritis encountered in infants and children is excellent. The major complications of neonatal, childhood, and gonococcal arthritis are loss of joint function resulting from damage to the articular surface. The highest incidence of these complications occurs with hip and shoulder infections, presumably resulting from avascular necrosis. The high incidence of concurrent suppurative arthritis with adjacent osteomyelitis in neonates places the epiphyseal growth plate at high risk for growth abnormalities. Neonates with osteomyelitis have an approximately 40% to 50% likelihood of growth disturbances with loss of longitudinal bone growth and ultimate limb shortening. There are no effective means to prevent hematogenous S. aureus arthritis. Universal immunization of infants with conjugate Hib vaccine has practically eliminated serious bacterial infections from this organism, including bone and joint infections.


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Pediatrics_Nelson. S. aureus arthritis. Universal immunization of infants with conjugate Hib vaccine has practically eliminated serious bacterial infections from this organism, including bone and joint infections. Acute conjunctivitis is usually a bacterial or viral infection of the eye characterized by a rapid onset of symptoms that persist for a few days. Nontypable Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis account for approximately two thirds of bacterial causes (Table 1191). Other causes include Neisseria gonorrhoeae and Pseudomonas aeruginosa, which is associated with extended-wear soft contact lenses. Viral conjunctivitis most commonly is caused by adenoviruses, which cause epidemic keratoconjunctivitis, and less frequently by coxsackieviruses and other enteroviruses. Keratitis, or inflammation of the cornea, is not commonly associated with conjunctivitis but occurs with N. gonorrhoeae, herpes simplex virus (HSV), and adenovirus infections.


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Pediatrics_Nelson. Neonatal conjunctivitis, or ophthalmia neonatorum, is purulent conjunctivitis during the first month of life, usually acquired during birth. The common causes of neonatal conjunctivitis, in order of decreasing prevalence, are chemical conjunctivitis secondary to silver nitrate gonococcal prophylaxis, Chlamydia trachomatis, common bacterial causes of conjunctivitis, Escherichia coli, other gram-negative enteric bacilli, HSV, and N. gonorrhoeae.


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Pediatrics_Nelson. Conjunctivitis is common in young children, especially if they come in contact with other children with conjunctivitis. Predisposing factors for bacterial infection include nasolacrimal duct obstruction, sinus disease, ear infection, and allergic disease when children rub their eyes frequently. Conjunctivitis occurs in 1% to 12% of neonates. A mild to moderate chemical conjunctivitis commonly is present from 24 to 48 hours of age in most newborns who receive ophthalmic silver nitrate as gonococcal prophylaxis. Approximately 50% of infants born vaginally to infected mothers have neonatal acquisition of C. trachomatis, in which the risk of chlamydial conjunctivitis (inclusion conjunctivitis) is 25% to 50%. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com Symptoms include redness, discharge, matted eyelids, and mild photophobia. Physical examination findings include chemosis, injection of the conjunctiva, and edema of the eyelids. Corneal involvement suggests gonococcal or herpetic infection. Herpetic corneal lesions appear as dendritic or ameboid ulcers or, more commonly, in recurrent infection, as a deep keratitis. Unilateral conjunctivitis with ipsilateral otitis media is often caused by nontypable H. influenzae. The timing and manifestations of neonatal conjunctivitis are helpful in identifying the cause (Table 119-2). N. gonorrhoeaecauses severe conjunctivitis with profuse purulent discharge. Chlamydial conjunctivitis usually occurs in the second week of life but may appear 3 days to 6 weeks after delivery. There is mild to moderate inflammation with purulent discharge issuing from one or both eyes.


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Pediatrics_Nelson. Cultures are not routinely obtained because bacterial conjunctivitis is usually self-limited or responds quickly to topical antibiotic treatment. If gonococcal conjunctivitis is suspected, especially in neonates, Gram stain and culture must be obtained. In these infants, blood and other sites of infection (such as cerebrospinal fluid) should be cultured. Additional testing for Chlamydia, human immunodeficiency virus (HIV), and syphilis should be performed on the mother and infant as necessary as well. Distinguishing bacterial from viral conjunctivitis by presentation and appearance is difficult (see Table 119-1). Vesicular lid lesions, if present, suggest HSV. Hyperpurulent conjunctivitis characterized by reaccumulation of purulent discharge within minutes is characteristic of N. gonorrhea infection. The differential diagnosis is delineated in Table 119-3.


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Pediatrics_Nelson. Blepharitis is associated with staphylococcal infections, seborrhea, and meibomian gland dysfunction. The child complains of photophobia, burning, irritation, and a foreign body sensation that causes the child to rub the eyes. Eyelid hygiene with an eyelid scrub routine is the initial step in treatment. Hordeola are acute suppurative nodular inflammatory lesions of the eyelids associated with pain and redness. External hordeola or styes occur on the anterior eyelid, in the Zeis glands, or in the lash follicles and usually are caused by staphylococci. Internal hordeola occur in the meibomian glands and may be infected with staphylococci or may be sterile. If the meibomian gland becomes obstructed, the gland secretions accumulate, and a chalazion develops. Hordeola usually respond spontaneously to local treatment measures but may recur.


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Pediatrics_Nelson. Dacryocystitis is an infection or inflammation of the lacrimal sac, which is usually obstructed, and is most commonly caused by Staphylococcus aureus or coagulase-negative staphylococci. A mucopurulent discharge can be expressed with Chemical: silver Variable (1%), Watery discharge 1–3 days No organisms on None None nitrate depending on use smear or culture of silver nitrate CSF, Cerebrospinal fluid; DIF, direct immunofluorescence; HSV, herpes simplex virus; PCR, polymerase chain reaction. Bacterial conjunctivitis Haemophilus influenzae, Mucopurulent unilateral or Topical antibiotics, parenteral Haemophilus aegyptius, bilateral discharge, normal ceftriaxone for gonococcus Streptococcus pneumoniae, vision, photophobia, conjunctival Neisseria gonorrhoeae injection and edema (chemosis); Viral conjunctivitis Adenovirus, echovirus, Same as for bacterial infection; Self-limited coxsackievirus may be hemorrhagic, unilateral


Pediatrics_Nelson

Pediatrics_Nelson. Viral conjunctivitis Adenovirus, echovirus, Same as for bacterial infection; Self-limited coxsackievirus may be hemorrhagic, unilateral Posterior uveitis (choroiditis) Toxoplasmosis, histoplasmosis, No signs of erythema, decreased Specific therapy for pathogen Toxocara canis vision Table 119-3 Differential Diagnosis of Ocular Infections—cont’d CONDITION ETIOLOGIC AGENTS SIGNS AND SYMPTOMS TREATMENT Episcleritis/scleritis Idiopathic autoimmune disease (e.g., SLE, Henoch-Schönlein purpura) Localized pain, intense erythema, unilateral; blood vessels bigger than in conjunctivitis; scleritis may cause globe perforation Episcleritis is self-limiting; topical steroids for fast relief Foreign body Occupational or other exposure Unilateral, red, gritty feeling; Irrigation, removal; check for visible or microscopic size ulceration CMV, Cytomegalovirus; EBV, Epstein-Barr virus; JIA, juvenile idiopathic arthritis; SLE, systemic lupus erythematosus.


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Pediatrics_Nelson. CMV, Cytomegalovirus; EBV, Epstein-Barr virus; JIA, juvenile idiopathic arthritis; SLE, systemic lupus erythematosus. gentle pressure on the nasolacrimal sac. Treatment usually requires probing of the nasolacrimal system to establish communication. Endophthalmitis is an emergent, sight-threatening infection that usually follows trauma, surgery, or hematogenous spread from a distant focus. Causative organisms include coagulase-negative staphylococci, S. aureus, S. pneumoniae, Bacillus cereus, and Candida albicans. Examination is difficult because of severe blepharospasm and extreme photophobia. A hypopyon and haze may be visible on examination.


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Pediatrics_Nelson. The lids should be treated as needed with warm compresses to remove accumulated discharge. Acute bacterial conjunctivitis is frequently self-limited, but topical antibiotics hasten resolution. Antibiotics are instilled between the eyelids four times a day until the discharge and chemosis subside. Recommended treatment includes topical trimethoprim-polymyxin B solution, sulfacetamide 5% solution, or erythromycin ointment. Ciprofloxacin solution should be restricted to corneal infections and resistant gram-negative infections in hospitalized patients. Gonococcal conjunctivitis in adults is treated with a single intramuscular (IM) dose of ceftriaxone (1 g) plus azithromycin (to treat possible concomitant chlamydial infection).


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Pediatrics_Nelson. The treatment of ophthalmia neonatorum depends on the cause (see Table 119-2). Gonococcal ophthalmia neonatorum is treated with a single dose of ceftriaxone (25 to 50 mg/kg intravenous [IV] or IM; maximum dose 125 mg). These infants should be hospitalized. Antibiotic treatment also is recommended for newborns to mothers with untreated gonorrhea. Chlamydial conjunctivitis is treated with oral erythromycin for 14 days, partly to reduce the risk of subsequent chlamydial pneumonia. The prognosis for bacterial and viral conjunctivitis is excellent. The major complication is keratitis, which can lead to ulcerations and perforation, and is uncommon except with N. gonorrhoeae and HSV infections. Chlamydial conjunctivitis may progress in infants to chlamydial pneumonia, which typically develops from 4 to 12 weeks of age (see Chapter 110).


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Pediatrics_Nelson. Careful hand washing is important to prevent spread of conjunctivitis. Bacterial conjunctivitis is considered contagious for 24 hours after initiating effective treatment. Children may return to school, but treatment measures must be continued until there is complete clinical resolution. All newborns, whether delivered vaginally or by cesarean section, should receive prophylaxis for gonococcal ophthalmia neonatorum as soon as possible after delivery. Silver nitrate 1% is used frequently but usually causes a chemical conjunctivitis. Alternative methods are equally effective and less irritating and include a single application of erythromycin 0.5% ointment or tetracycline 1% ointment.


Pediatrics_Nelson

Pediatrics_Nelson. Many diseases or their treatments adversely affect the immune system, including genetic immunodeficiencies, human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), cancer, stem cell and organ transplantation, and immunosuppressive drugs used to treat cancer, autoimmune diseases, and transplant patients. These patients are at significant risk of life-threatening infections from invasive endogenous infection from bacterial or fungal flora of the oropharynx, skin, and gastrointestinal tract, acquisition of exogenous infection from infected persons, and reactivation of latent infections until immune function recovers (Table 120-1).


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Pediatrics_Nelson. The infections seen in immunocompromised persons canoften be predicted by which component of the immune system isabnormal, and the evaluation of fever in immunocompromisedhosts differs. Episodes of fever and neutropenia, defined as an absolute neutrophil count of less than 500/mm3 neutrophilsand bands, are especially common in cancer and transplant patients and increase risk for bacterial and fungal infections. The use of corticosteroids and potent immunosuppressive drugs that impair the activation of T lymphocytes increases the risk for pathogens normally controlled by T cell–mediated responses, such as Pneumocystis jiroveci and Toxoplasma gondii, and intracellular pathogens, such as Salmonella, Listeria, and Mycobacterium.


Pediatrics_Nelson

Pediatrics_Nelson. Staphylococcus aureus, Escherichia coli, Pseudomonasaeruginosa, Klebsiella pneumoniae, and coagulase-negativestaphylococci are the most commonly identified bacterialpathogens in immunocompromised persons. Central indwelling catheters often are associated with infections caused bycoagulase-negative staphylococci, S. aureus, gram-negative bacteria, Enterococcus, and Candida. Fungal pathogens account for approximately 10% of all infections associated with childhood cancer. Candida causes 60% of all fungal infections, with Aspergillus as the second most common pathogen. Other risk factors for fungal infections include oropharyngeal and gastrointestinal mucositis Clostridium difficile Candida spp. Cystoisospora belli Echoviruses Enterobacter cloacae Fusarium spp. Septata intestinalis Human herpes virus 6


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Pediatrics_Nelson. Clostridium difficile Candida spp. Cystoisospora belli Echoviruses Enterobacter cloacae Fusarium spp. Septata intestinalis Human herpes virus 6 Chapter 120 u Infection in the Immunocompromised Person 391 facilitating systemic fungal invasion, presence of long-term indwelling intravascular catheters, extreme prematurity, and broad-spectrum antibacterial therapy that promotes fungal colonization as a precursor to infection. Infection with T. gondii represents reactivation of quiescent infection facilitated by cancer-associated or therapy-associated cellular immunodeficiency. P. jirovecii primarily causes pneumonitis in patients with leukemia, lymphoma, HIV or those on long-term corticosteroids, but can also cause extrapulmonary disease (sinusitis, otitis media).


Pediatrics_Nelson

Pediatrics_Nelson. Viral opportunistic infections in patients with cancer usually represent symptomatic reactivation from latency facilitated by cancer-associated or therapy-associated cellular immunodeficiency. Herpes simplex virus (HSV) can cause severe and prolonged mucocutaneous infection or disseminated disease. Cytomegalovirus (CMV) can cause focal disease in immunocompromised persons, especially in stem cell transplant patients. Manifestations of CMV disease include hepatitis, pneumonitis, esophagitis, encephalitis, and enteritis with gastrointestinal ulcerations. Reactivation of Epstein-Barr virus (EBV) is associated with posttransplant lymphoproliferative disorder. Varicella zoster virus (VZV) can cause serious primary infection in susceptible persons, often with accompanying encephalitis, hepatitis, or, most ominously, pneumonitis. Zoster also can reactivate during chemotherapy and may be disseminated.


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Pediatrics_Nelson. Chemotherapeutic agents target rapidly dividing cells, especially myeloproliferative cells, which cause myelosuppression.Children receiving allogeneic transplants are at greater riskfor infection than children receiving autologous transplants.Prolonged time to hematologic engraftment is a significantrisk factor for infection in these patients. Children receiving stem cell or organ transplants have significantly greaterimmunosuppression as a consequence of the myeloablative conditioning regimens. Foreign bodies (shunts, centralvenous catheters) interfere with cutaneous barriers againstinfection and together with neutropenia or immunosuppression increase the risk of bacterial or fungal infections (seeChapter 121). The relative rate of infection in patients with cancer at admission or during hospitalization is 10% to 15%. The most frequently infected sites, in descending order, are the respiratory tract, the bloodstream, surgical wounds, and the urinary tract.


Pediatrics_Nelson

Pediatrics_Nelson. Available @ StudentConsult.com Fever is the most common, and sometimes the only, presenting symptom of serious infection in cancer and transplant patients. The presence of fever with neutropenia, even in the absence of other signs or symptoms, demands prompt evaluation because of the potential for life-threatening infection. Despite being immunocompromised, these patients develop fever and some typical signs and symptoms associated with infections. All symptoms and signs should be evaluated thoroughly. However, some symptoms may be absent based on the underlying immunodeficiency. For example, in the absence of neutrophils to contain and induce localized signs of inflammation, determination of the source of infection by physical examination is often difficult. Chest findings may be absent, despite pneumonia, and revealed only by chest radiograph at presentation or when the neutrophil count recovers.


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Pediatrics_Nelson. Assessing fever and neutropenia in immunocompromised persons requires blood cultures for bacterial and fungal pathogens obtained by peripheral venipuncture and from all lumens of any indwelling vascular catheters. A complete blood count with differential, C-reactive protein, complete chemistry panel, culture of urine and Gram staining/culture of potential sites of specific infection found during history and physical should be performed. Antigen tests, especially for serum cryptococcal antigen, should be considered. Chest radiographs are important to assess for the presence of pulmonary infiltrates. Specialized imaging studies, such as the CT or MRI, can be useful in selected cases, such as with suspected sinusitis or intra-abdominal infection, or to further delineate the location and extent of abnormalities seen on plain radiographs. Sinus infection with bacteria, Aspergillus, or Zygomycetes is common in neutropenic hosts and may be detected only on the CT scan.


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Pediatrics_Nelson. Initially the patient should have a complete physical examination, including careful scrutiny of the oropharynx, nares, external auditory canals, skin and axilla, groin, perineum, and rectal area. The exit site and subcutaneous tunnel of any indwelling vascular catheter should be examined closely for erythema and palpated for tenderness and expression of purulent material. Perirectal abscess is a potentially serious infection in neutropenic hosts, with tenderness and erythema that may be the only clues to infection. Any presumptive infection identified during the evaluation should direct appropriate cultures and tailor anti-infective therapy.


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Pediatrics_Nelson. Treatment should be provided as appropriate for focal infections identified by physical examination or diagnostic imaging. Select low-risk patients may be managed as outpatients. Empirical treatment of fever and neutropenia without an identified source should include an extended-spectrum penicillin or cephalosporin with activity against gram-negative bacilli, including P. aeruginosa, sometimes in combination with an aminoglycoside (Fig. 120-1). If the patient has an indwelling vascular catheter, vancomycin should be added because of the increasing prevalence of methicillin-resistant S. aureus but can be discontinued if S. aureus is not cultured after 48 to 72 hours. Specific antibiotic regimens should be guided by local antibiotic resistance patterns at each institution. No source of infection identified Empirical anti-infective therapy Fever (38.5C) and neutropenia (granulocytes <500/mm3) Focal infection Specific therapy directed against most likely pathogens


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Pediatrics_Nelson. No source of infection identified Empirical anti-infective therapy Fever (38.5C) and neutropenia (granulocytes <500/mm3) Focal infection Specific therapy directed against most likely pathogens Figure 120-1 Initial management of fever and neutropenia without an identified source in cancer and transplant patients. (From Conrad DA: Patients with cancer. In Jenson HB, Baltimore RS, editors: Pediatric Infectious Diseases: Principles and Practice, ed 2, Philadelphia, 2002, Saunders, p 1161.)


Pediatrics_Nelson

Pediatrics_Nelson. If no microbiologic cause is isolated, empirical broad-treatment with amphotericin B or another antifungal agent spectrum antibiotics are continued as long as the patient is instituted in patients who have neutropenia and persistent remains neutropenic, regardless of whether the fever resolves fever without a focus, despite broad-spectrum antibacterial (Fig. 120-2). Antibiotic therapy should be modified as indi-therapy for approximately 5 days (see Fig. 120-2).cated by new findings or if the patient’s clinical status deterio-The use of recombinant granulocyte colony-stimulating rates. Further investigation for fungal infection and empirical factor or granulocyte-macrophage colony-stimulating factor plus Add: If: plus Substitute: If:


Pediatrics_Nelson

Pediatrics_Nelson. Figure 120-2 Continuing management of possible infection after 7 days of fever without an identified source in cancer and transplant patients. (From Conrad DA: Patients with cancer. In Jenson HB, Baltimore RS editors: Pediatric Infectious Diseases: Principles and Practice, ed 2, Philadelphia, 2002, Saunders, p 1165.) Chapter 120 u Infection in the Immunocompromised Person 393 stimulates neutrophil production by the bone marrow, reduces the duration and severity of neutropenia, and decreases the risk of infection. Some chemotherapeutic protocols for the treatment of solid tumors that result in prolonged neutropenia incorporate hematopoietic cytokine therapy as part of the treatment protocol.


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Pediatrics_Nelson. Current guidelines discourage the use of broad-spectrum prophylactic antibiotics to prevent fever and neutropenia becauseof lack of efficacy and concerns about development of antibioticresistance. Administration of trimethoprim-sulfamethoxazole to prevent P. jiroveci infection is routine for patients undergoing intensive chemotherapy or immunosuppression for transplantation. Prophylaxis generally is begun with initiation ofanticancer therapy and continued until 6 months after chemotherapy has been completed. In select populations, such aspatients undergoing hematopoietic stem cell transplantation,prophylactic antifungals such as fluconazole are beneficial.


Pediatrics_Nelson

Pediatrics_Nelson. Immunocompromised susceptible persons exposed to chickenpox within 2 days before the onset of rash until 5 days after the onset of rash in the index case should receive varicella zoster immune globulin (VZIG). Modified infection after VZIG may not result in protective immunity, and persons who receive VZIG prophylaxis should be considered still at risk with any subsequent exposures. Infections are a common and important complication of medical devices and are a major part of health care–associated infections (formerly known as nosocomial infections). Vascular catheters are inserted in most inpatients and used in many outpatients. The use of catheters for long-term access to the bloodstream has been an important advance for the care of persons who require parenteral nutrition, chemotherapy, or extended parenteral antibiotic therapy. The major complication of catheters is infection.


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Pediatrics_Nelson. Short, peripheral intravenous (IV) catheters used for short-term access in stable patients are associated with a low rate of infection, especially in children. Peripherally inserted central catheters are commonly used for short-term venous access. Central catheters are commonly placed for extended venous access, such as for chemotherapy, using tunneled silicone elastomer catheters (Broviac or Hickman catheters) that are surgically inserted into a central vein, passed through a Gram-positive Coagulase-negative Diphtheroids, organisms staphylococci, Bacillus, Staphylococcus Micrococcus aureus, Enterococcus Gram-negative Escherichia Acinetobacter, organisms coli, Klebsiella, Enterobacter, Pseudomonas Neisseria aeruginosa


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Pediatrics_Nelson. Gram-negative Escherichia Acinetobacter, organisms coli, Klebsiella, Enterobacter, Pseudomonas Neisseria aeruginosa Fungi Candida albicans Malassezia furfur, Candida parapsilosis, Candida glabrata, Candida tropicalis subcutaneous tunnel before exiting the skin, and anchored by a subcutaneous cuff. Contamination of the catheter hub or any connection of the IV tubing is common and is a major predisposition to catheter-associated infection. Totally implanted venous access systems (Port-a-Cath, Infuse-a-Port) have a silicone elastomer catheter tunneled beneath the skin to a reservoir implanted in a subcutaneous pocket. Implanted catheters or ports decrease, but do not eliminate, the opportunity for microbial entry at the skin site.


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Pediatrics_Nelson. Catheter-related thrombosis and catheter-related infection can develop separately or together. Ultrasound or radiographscan identify thrombi, but infection can be identified by culture only. Thrombophlebitis is inflammation with thrombosis. Septic thrombophlebitis is thrombosis with organisms embedded in the clot. Catheter-related bloodstream infection implies isolation of the same organism from a catheterand from peripheral blood of a patient with clinical symptomsof bacteremia and no other apparent source of infection. Confirmation requires quantitative colony counts of both samples,which is not routinely performed. Possible sources of the bacteremia include the infusate, contamination via tubing and catheter connections, or established infection, which may or maynot be clinically apparent. Infection may appear as an exit site infection limited to the insertion site or may extend along thecatheter tunnel of buried catheters to cause a tunnel infection.


Pediatrics_Nelson

Pediatrics_Nelson. Many microorganisms cause catheter-related infections, most commonly Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus, and Candida (Table 121-1).Gram-positive cocci, primarily staphylococci, cause more than 50% of central venous catheter associated bacteremias and exit site infections. Other skin flora, diphtheroids, and Bacillus are often involved. Gram-negative organisms cause 25% to 40% of infections. Polymicrobial infections of central venous catheters are common. Fungal catheter infections, usually Candida albicans, are most common among persons receiving broad-spectrum antibiotics or parenteral nutrition. The rates of bloodstream infection of peripheral venous catheters are from 0 to 2 per 1000 catheter-days and for central catheters from less than 2 to 30 per 1000 catheter-days. Risk factors for infection include prematurity, burns and skin disorders that adversely affect the skin integrity, neutropenia, and


Pediatrics_Nelson

Pediatrics_Nelson. Chapter 121 u Infections Associated with Medical Devices 395 Tunneled? Tunneled? Hemodynamically unstable or no improvement after 72 hours persistently positive culture or endocarditis/ thrombophlebitis or pocket infection cellulitis AND: NOT TERMINALLY ILL LINE NEEDED? YES1 line >1 line Antibiotic through all lumina consider thrombolytic agents YES NO NO YES NO YES NO NO Insertion easy? REMOVE THE LINE YES Figure 121-1 Management of central venous catheter infection. (From De Paw BE, Verweij PE: Infections in patients with hematologic malignancies. In Mandell GL, Bennett JE, Dolin R, editors: Principles and Practice of Infectious Diseases, ed 6, Philadelphia, 2005, Churchill Livingstone, Fig. 307-1, p 3434.) other immunodeficiencies (see Chapter 120). Infection rates are lower for tunneled and implanted catheters. Catheters inserted in emergency settings are more likely to be infected than catheters placed electively.


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Pediatrics_Nelson. Clinical signs of catheter-associated bacteremia or fungemia range from mild fever to overwhelming sepsis. Infection at the site of the central catheter entrance is manifested as a localized cellulitis with warmth, tenderness, swelling, erythema, and discharge. Tunnel infection is manifested by similar findings along the tunnel route. Peripheral phlebitis or catheter-related infection is classically manifested as a warm, erythematous, tender palpable cord originating at the IV catheter site but may be subclinical or manifested only by fever without signs of local inflammation. Available @ StudentConsult.com


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Pediatrics_Nelson. Available @ StudentConsult.com The treatment of catheter-related infection depends on the site of the infection and the pathogen involved. Catheters that are no longer necessary should be removed if infection is suspected. Catheter-associated bacteremia can be treated with simple catheter removal, removal plus antibiotics, or, in a stable patient, an attempt of antibiotic therapy alone (Fig. 1211). Infection with organisms of low virulence may be manifested by fever alone, and removal of the catheter frequently is followed by prompt defervescence and complete resolution of infection. Empirical initial therapy for suspected infection should include antibiotics active against gram-negative organisms such as a broad-spectrum cephalosporin, and against


Pediatrics_Nelson

Pediatrics_Nelson. S. aureus and coagulase-negative staphylococci such as oxacillin, nafcillin, or vancomycin. Antibiotic regimens should be tailored to the specific organism identified. Eradication of infection can be accomplished without removal of the central line in 89% of uncomplicated bacteremic infections, 94% of exit site infections, and 25% of tunnel infections. If the patient is not critically ill and the pathogen is likely to be susceptible to antibiotic therapy, a trial of antibiotics is given through the infected catheter. The total duration of therapy depends on the pathogen and the duration of positive cultures and is usually 10 to 14 days after sterilization of the bloodstream. Catheter removal is indicated with sepsis, septic thrombophlebitis, clinical deterioration (despite appropriate therapy), persistently positive blood culture results after 48 to 72 hours of appropriate antimicrobial therapy, embolic lesions, or fungal infection because of poor response to antifungal therapy alone


Pediatrics_Nelson

Pediatrics_Nelson. persistently positive blood culture results after 48 to 72 hours of appropriate antimicrobial therapy, embolic lesions, or fungal infection because of poor response to antifungal therapy alone (see Fig. 121-1). Infection of the pocket around an implanted port is unlikely to respond to antibiotics, and removal of the foreign body is usually necessary.


Pediatrics_Nelson

Pediatrics_Nelson. Antibiotic-lock is a method of sterilizing intravascular catheters by using high concentrations of antibiotics infused into the portion of the catheter between the hub and the vessel entry. The solution is allowed to dwell within the catheter segment for several hours. It also may be useful for treatment of catheter-associated infections and for prevention of infection. Aseptic technique is essential during catheter insertion. Catheters that are placed during emergency situations should be replaced as soon as medically feasible. Care of indwelling catheters involves meticulous attention to sterile technique whenever the system is entered. Care of the catheter entry site commonly involves a topical antibiotic or disinfectant. Catheters that are no longer necessary should be removed.


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Pediatrics_Nelson. Intubation of the airway provides direct access to the lungs and bypasses normal host defenses. Organisms enter the lungs directly through the lumen of the tube or by descending around the tube, which may result in ventilator-associated pneumonia. Contaminated respiratory equipment, humidification systems, or condensate introduces bacteria directly into lower airways. The continuously open upper airway increases the risk of aspiration of oropharyngeal flora and reflux of gastric contents and interferes with clearance of the airway by coughing because an effective cough requires a closed glottis. Suctioning of the upper respiratory tract or mouth requires clean technique but does not require aseptic technique. Suction catheters that reach the lower airways must be sterile and usually are designed for single use.


Pediatrics_Nelson

Pediatrics_Nelson. The most important risk factors for urinary tract infections (UTIs) are the presence of catheters, instrumentation, and anatomic abnormalities (see Chapter 114). Organisms enter the bladder through the catheter by instillation of contaminated irrigation fluids, backflow of contaminated urine from the drainage bag, or ascent of bacteria around the meatus along the outside of the catheter. Indwelling catheters facilitate direct access to the bladder and should have a closed drainage system. After simple, straight catheterization, the incidence of UTI is 1% to 2%. Organisms that cause catheter-associated UTIs include fecal flora, such as gram-negative enteric bacilli, most commonly Escherichia coli, and Enterococcus. With concomitant antibiotic treatment, resistant organisms predominate, and fungi emerge as pathogens.


Pediatrics_Nelson

Pediatrics_Nelson. The most important aspect of prevention is to minimize the duration and use of catheterization. Intermittent catheterization is preferred over indwelling catheter drainage whenever feasible. Insertion of catheters must be performed with aseptic technique, and the drainage system must remain closed at all times, with sterile technique used whenever the system is entered. Drainage bags always should be dependent to avoid backflow of urine into the bladder. Indwelling catheters used for peritoneal dialysis may develop exit site infections, tunnel infections, or lead to peritonitis. The usual route of infection is from the skin surface along the tunnel and into the peritoneum. The most common pathogens are skin flora, including Staphylococcus; organisms that contaminate water, such as Pseudomonas and Acinetobacter; enteric flora, such as E. coli and Klebsiella; and fungi, such as


Pediatrics_Nelson

Pediatrics_Nelson. C. albicans. Peritonitis may present with fever, vague abdominal pain, and cloudy dialysate. The diagnosis is established on clinical manifestations and confirmed by culture of the dialysate. Prevention of infection requires careful planning of the location of the exit site to minimize contamination, aseptic insertion of the catheter, meticulous care of the catheter site, securing of the catheter to avoid tension and motion, and aseptic technique during dialysis. Important risk factors of health care–associated central nervous system infections are surgery, ventriculoperitoneal shunts, and cerebrospinal fluid (CSF) leaks. Infection of ventriculoperitoneal shunts results from contamination of the system at the time of placement or from hematogenous seeding. Externalized ventricular drains and subdural bolts allow direct access of skin flora to the CSF. For these devices, the rates of infection increase with the duration of catheterization, especially beyond 5 days.


Pediatrics_Nelson

Pediatrics_Nelson. The most common pathogens causing shunt infections are coagulase-negative staphylococci and S. aureus. After skull fracture or cranial surgery, a CSF fistula leak may facilitate ascending infection from the nasopharynx, especially with Streptococcus pneumoniae, which frequently colonizes the nasopharynx. Patients with shunt infections may present with only fever and headache, or may present with typical signs and symptoms of meningitis (see Chapter 100). Infections caused by coagulase-negative staphylococci typically present with insidious onset of fever, malaise, headache, and vomiting. Empirical therapy is with vancomycin, with additional antibiotics if gram-negative bacteria are suspected.


Pediatrics_Nelson

Pediatrics_Nelson. Antibiotics frequently are used perioperatively during placement of shunts and other neurosurgical procedures. There is no proof that antibiotics decrease infection rates in these clean procedures. External ventricular drains should be maintained as closed systems with aseptic technique and removed as soon as possible. Drainage bags always should be dependent to avoid backflow.