Infectious Disease Issues

From Family Medicine Board Review Course, presented July 6-9, 2009, by the Department of Family and
Community Medicine, University of California, San Francisco, School of Medicine

Kevin Coulter, MD, Chief, Division of General Pediatrics, University of California Davis Children’s Hospital, Sacramento

Educational Objectives

The goal of this program is to improve the management of infectious childhood diseases. After hearing and assimilating this program, the clinician will be better able to:

1.   Determine the appropriate timing for vaccinations.

2.   List contraindications to childhood vaccinations.

3.   Recognize signs and symptoms of infectious childhood diseases.

4.   Recommend appropriate treatments for infectious diseases, based on patient age, etiology, and radiographic and clin­ical findings.

5.   Describe differential diagnoses of various infectious diseases.

Faculty Disclosure

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the plan­ning committee to disclose relevant financial relationships within the past 12 months that might create any personal con­flicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, Dr. Coulter and the planning committee re­ported nothing to disclose.

Acknowledgments

Dr. Coulter spoke in San Francisco, CA, at Family Medicine Board Review Course, presented July 6-9, 2009, by the Depart­ment of Family and Community Medicine, University of California, San Francisco, School of Medicine. The Audio-Digest Foundation thanks Dr. Coulter and the Department of Family and Community Medicine, University of California, San Fran­cisco, School of Medicine for their cooperation in the production of this program.

General vaccination schedule (2009): hepatitis B virus (HBV)  —  first dose recommended before nursery discharge; pay special attention to hepatitis B immune globulin (HBIG) in infants born to hepatitis B surface antigen (HB­sAg)-positive mothers; test for HBsAg and anti-HBV at age 9 to 15 mo; diphtheria and  tetanus toxoids and acel­lular pertussis (DTaP)  —  administer fourth dose as early as age 12 mo, provided first 3 doses done in timely fashion; fifth dose not necessary if fourth dose given late (eg, at ³4 yr of age); measles-mumps-rubella (MMR)  —second dose routinely given at age 4 to 6 yr to capture nonresponders to first dose; varicella  —  administer sec­ond dose at 4 to 6 yr of age; pneumococcal conjugate (Prevnar)  —  recommended for children <5 yr of age; effec­tive in preventing invasive pneumococcal disease in children <2 yr of age; influenza  —  recommended for children 6 mo to 18 yr of age; diphtheria, reduced tetanus toxoids and acellular pertussis (TdaP)  —  1 dose at age 11 yr if DTP/DTaP series completed, and in older children if any doses missed; acellular pertussis vaccine gives prolonged immunity (recommended for all ages); adults and adolescents (who became infected when immunity from whole cell pertussis vaccine waned) main sources of pertussis infection in infants; meningococcal conjugate vaccine  —recommended for all 11- to 12-yr-olds; college students living in dormitory; military; children with complement deficiencies; hepatitis A vaccine  —licensed for children ³1 yr of age; 2 doses 6 mo apart; rotavirus  —  newer vac­cine given in 2 doses through latex plunger; contraindicated for children at risk of developing latex allergies (eg, children who need multiple surgeries for spina bifida)

General vaccine information: speaker recommends adding rotavirus to live virus vaccines, no need to restart vac­cine series if interrupted; refer to guidelines for minimum allowable time between vaccines; acceptable to give all vaccines in combination (£5 at one time); children taking significant doses of corticosteroids should not be given live viruses (acceptable if taking lower daily doses, alternate day dosage, or inhaled or topical steroids); all routine inactivated vaccines can be given to children with HIV (MMR, and varicella for children with Class 1 HIV with mild or no disease); MMR and varicella contraindicated if household member immunosuppressed; vaccinate pre­mature infants at appropriate chronologic age (not on age-adjusted schedule); all vaccinations acceptable during breastfeeding; delay MMR up to 1 yr after administration of intravenous immunoglobulin (IVIG); refer to “red book” for specific guidelines; minor illnesses with low-grade fever do not contraindicate vaccination; contraindica­tions for immunization with pertussis vaccine  —  anaphylactic reaction to vaccine; encephalopathy developing within 7 days of vaccine; precautions for vaccinations with pertussis vaccine  —  collapse or shock-like state; seizure within 3 days (most likely febrile rather than antigen-related)

Tuberculosis (TB) in children: clinical manifestations  —asymptomatic with normal chest x-ray; usually discovered by routine tuberculin skin testing (TST) or because of contact with high-risk adult at home; may present with typical symptoms; radiographic findings  —  mostly hilar or mediastinal adenopathy; occasional large pleural ef­fusion; epidemiology  —  infected infants at increased risk for progression; represents public health sentinel event; children not generally contagious; diagnosis  —  gastric aspirates best source of organism

Tuberculin skin testing: Mantoux method; test children at increased risk for disease only; immediate TSTs  —  contacts of confirmed or suspicious cases; children who have traveled to areas with endemic disease; children with clinical find­ings; annual TSTs  —  children with ongoing exposure to contacts at high risk; TSTs every 2 to 3 yr  —  children exposed to contacts at some risk; children in areas of high TB burden; routine TSTs at 4 to 6 yr of age and 11 to 16 yr of age for children of parents from endemic countries and living in high-prevalence areas; definition of positive TST  —  >5 mm in children in close contact with person with active disease or children with clinical symptoms; >10 mm in chil­dren <4 yr of age or at increased risk for dissemination because of, eg, Hodgkin’s lymphoma; >15 mm in children >4 yr of age with no risk factors

Treatment: with positive TST and normal chest x-ray, isoniazid (INH) for 9 mo (monitoring of liver function not usually necessary); for children in contact with contagious disease, do TST, give INH for 3 mo if TST negative, and repeat TST; if still negative, stop treatment; TST and Bacillus Calmette-Guerin (BCG)  —  American Acad­emy of Pediatrics recommends same criteria for interpreting TST results in children previously immunized with BCG; if BCG £2 yr ago, chest x-ray normal, and TST £10 mm, consider not treating; if BCG 4 to 5 yr ago and TST  ³ 15 mm, ignore BCG and treat for TB

Pharyngitis: etiology  —  caused mostly by viral infections (eg, adenovirus; causes purulence and adenopathy); 15% of cases caused by group A streptococci (GAS); bacterial vs viral infection  —  scarlet fever rash, headache, abdom­inal pain, sore throat in absence of viral symptoms, and palatal petechiae may indicate GAS; tender cervical lymph­adenitis; GAS pharyngitis not generally observed in children <2 yr of age; if present, GAS found in nares with purulent, foul-smelling rhinitis with occasional nasal bleeding and lymphadenopathy; evaluation  —  throat culture remains gold standard; rapid antigen tests highly specific and variably sensitive; follow negative antigen tests with culture; no need to get culture from younger children, children with viral symptoms, or pets; follow-up GAS cul­tures after treatment not necessary; treatment of GAS  —  to prevent acute rheumatic fever, and poststreptococcal glo­merulonephritis; penicillin V bid for children and teenagers for 10 days; single injection of benzathine penicillin G; single daily dose of amoxicillin; macrolide; first generation cephalosporin; symptoms of GAS  —  confluent erythema of cheeks that spares area around mouth (perioral pallor); 5 to 7 days later, desquamation of palms and knees; beefy red indurated perianal tissue may indicate perianal GAS cellulitis

Acute otitis media: peak incidence occurs at 6 to 18 mo and 5 to 6 yr of age; majority resolve without treatment; treatment generally beneficial; acute onset of signs and symptoms in presence of bulging tympanic membrane (TM), decreased TM mobility, air-fluid level behind TM, and distinct otalgia; treatment  —  antibiotics for all children <6 mo of age, age of 6 mo to 2 yr only with certain diagnosis, and age of ³2 yr only with certain diagnosis and severe disease; consider observation for 48 to 72 hr in children 6 mo to 2 yr of age with uncertain diagnosis and nonsevere disease, and in children ³2 yr of age with uncertain diagnosis or with certain diagnosis and nonsevere disease; high-dose amoxicillin standard; treat children <6 yr of age for 10 days; treat children ³6 yr of age with nonsevere disease for 5 to 7 days; high-dose amoxicillin clavulanate (eg, Augmentin) first-line for patients with severe disease and high fever; ceftriaxone first-line for type 1 penicillin-allergic patients with severe disease; treatment failures after 48 to 72 hr  —  switch to amoxicillin clavulanate if nonsevere and started on amoxicillin; consider ceftriaxone or clindamycin if patient allergic to penicillin; consider ceftriaxone for patients with severe disease  who fail amoxicillin clavulanate; prevention  —  altering home environment (eg, eliminating smoking, reducing time in daycare, eliminating pacifiers) considered more effective than prophylactic antibiotics; consider tympa­nostomy tubes

Sinusitis in children: diagnosed clinically; as frontal sinuses develop at »6 yr of age, diagnosis more common after this age; predispositions  —  cystic fibrosis; allergic rhinitis and/or asthma; ciliary dysmotility (Kartagener’s syn­drome); diagnosis  —  respiratory complaints (eg, rhinorrhea, day or night cough); radiologic diagnosis  —  x-rays not generally recommended; computed tomography (CT) for recurrent sinusitis and orbital cellulitis; etiology  —Strep­tococcus pneumoniae; Haemophilus influenzae; Moraxella catarrhalis; Staphylococcus aureus; treatment  —high-dose amoxicillin or amoxicillin clavulanate for 10 to 14 days; Pott's puffy tumor  —  swelling and tenderness at lower forehead over frontal sinus; sinusitis can erode frontal bone and invade soft tissue beneath

Pneumonia: etiology and management according to age and severity

Febrile ill-appearing infants with lobar consolidation: etiology  —  S pneumoniae and S aureus; H influenzae less common; diagnosis  —  blood culture; consider lumbar puncture (LP); treatment  —  ceftriaxone; clindamycin or vancomycin plus ceftriaxone if pleural effusion present and S aureus suspected

Afebrile well-appearing infants with bilateral interstitial infiltrates: etiology  —  Chlamydia trachomatis; pertussis; treatment  —  macrolides; C trachomatis associated with staccato cough at age £4 mo and elevated C trachomatis-specific IgM

Febrile ill-appearing toddlers, preschoolers, and adolescents with lobar consolidation: etiology  —  S pneumoniae; S au­reus; treatment  —  intramuscular (IM) ceftriaxone, high-dose amoxicillin clavulanate or high-dose amoxicillin for out­patients; ceftriaxone and vancomycin or clindamycin for inpatients; outpatients with high white blood cell (WBC) count and bacterial etiology can be treated with high–dose amoxicillin clavulanate, high-dose amoxicillin, or IM ceftri­axone; azithromycin-treated outpatients with lobar consolidation often fail and present to emergency department with pleural effusion or empyema

Well-appearing toddlers, preschoolers, and adolescents with diffuse interstitial infiltrates: etiology  —  respiratory syncytial virus and influenza in winter; parainfluenza; pertussis (with persistent cough and high, predominantly lymphocytic WBC count); M pneumoniae; treatment  —  macrolides

Croup: subglottic edema and viral infection, particularly with parainfluenza virus; observed in younger children (small airways easily compromised by edema); barking cough; stridor; clinical diagnosis, rather than by anteropos­terior (AP) and lateral cervical x-rays; lateral views show air in hypopharynx due to subglottic swelling; differential diagnosis  —  epiglottitis; consider lateral cervical x-ray or CT if peritonsillar or retropharyngeal abscess suspected; foreign body; treatment  —  admit children with stridor at rest, retractions, or hypoxia; racemic epinephrine effective, but does not change course of illness (requires dexamethasone [eg, Decadron] or prednisone); speaker advises fol­lowing dexamethasone with short course of prednisone when treating as outpatient

Urinary tract infections (UTIs): occur in infants <1 yr of age; predominant in girls >1 yr of age; risk increased in uncir­cumcised boys; neonatal  —  significant bacteremia; if age <8 wk and infant febrile, admit, treat intravenously, and obtain blood cultures; speaker recommends LP; microbiology  —Escherichia coli; Proteus in boys; Staphylococcus saprophyti­cus in sexually active teenagers with recurrent UTIs and/or abnormal urinary tracts; diagnosis  —  catheterization in infants <2 yr of age; clean catch in children >2 yr of age; leukocyte esterase; nitrites; inpatient treatment  —  7 to 14 days of ceftri­axone as first line; follow-up cultures not necessary if child afebrile; indications for imaging  —  acute pyelonephritis; first UTI in boy; first UTI in girl <3 yr of age; UTI in child with voiding abnormalities, high blood pressure, or poor growth (significant risk for renal malformations); perform ultrasonography and voiding cystourethrography to exclude obstruc­tion or vesicoureteral reflux

Meningitis: neonatal  —  enterovirus (eg, coxsackievirus, echovirus); group B streptococci (GBS); Listeria mono­cytogenes; E coli; 1 to 3 mo of age  —  neonatal plus community-acquired organisms (CAO); 3 to 36 mo of age  —generally only CAO; treatment  —  based on age and likely bacterial etiology; start patients at risk for CAO on van­comycin; dexamethasone effective in preventing deafness and sensorineural hearing loss due to H influenzae men­ingitis (now uncommon)

Kawasaki disease: most common cause of persistent fever without source; leading cause of acquired heart disease in chil­dren if not adequately treated; diagnostic criteria  —  fever for ³5 days; bulbar conjunctivitis; red cracked lips; strawberry tongue; erythema and induration of hands and feet; cervical adenopathy (single node) seen in 50% of patients; coronary artery aneurysms develop in 15% to 25% of untreated patients; risk factors for coronary artery aneurysms  —  male sex; high fever of long duration; thrombocytopenia; hypoalbuminemia; differential diagnosis  —  measles; scarlet fever; toxic shock syndrome; juvenile idiopathic arthritis; observed in younger children (particularly in Asians); associated findings  —  sterile pyuria; mild elevations of liver transaminases; arthritis; pleocytosis in cerebrospinal fluid; pancarditis with pericardial effusion; right upper quadrant pain and mass (due to hydropic gallbladder); treatment  —  1 to 2 doses of IVIG; high-dose aspirin; echocardiography; cardiology evaluation; parvovirus B19  —  causes erythema infectiosum; se­lectively inhibits precursors of red blood cells, with resulting anemia (transient erythroblastopenia of childhood)

Other childhood diseases: coxsackievirus  —  prevalent in summer and fall; lesions in palms and back of throat (her­pangina); roseola  —  caused by human herpesvirus 6; clinical presentation includes high fever, rash 3 days after fe­ver, and postoccipital adenopathy; most common cause of febrile seizures; pinworm infections  —  eggs laid on perianal tissue (occasionally in vagina); treatment includes mebendazole and hygienic measures; scabies  —  in in­fants, presents on face and has predilection for axillae; treat with permethrin (eg, Elimite)

Questions and answers: QuantiFERON Gold  —  TST alternative; done in one visit; follow-up TST not needed; more specific than TST; more commonly used in public health arena for tracing contacts; pneumococcal vaccine  —  data suggest decreased rates of invasive pneumococcal disease (especially meningitis) since introduction; co-occurring conjunctivitis and otitis media  —  historically, caused by H influenzae; now, more likely S pneumoniae; single-dose amoxicillin for otitis media  —  not advised; give high-dose amoxicillin bid

Suggested Reading

Araujo Z et al: The effect of Bacille Calmette-Guerin vaccine on tuberculin reactivity in indigenous children from communities with high prevalence of tuberculosis. Vaccine 26:44, 2008; Bjornson CL, Johnson DW: Croup. Lancet 371:9609, 2008; Chan BC et al: Age-specific cut-offs for the tuberculin skin test to detect latent tuberculosis in BCG-vaccinated children. Int J Tuberc Lung Dis 12:12, 2008; Committee on Infectious Diseases, American Academy of Pediatrics: Prevention of rotavirus disease: updated guidelines for use of rotavirus vaccine. Pediatrics 5:123, 2009; Dagan R, Klugman KP: Impact of conjugate pneumococal vaccines on antibiotic resistance. Lancet Infect Dis 8:12, 2008; Falagas ME et al: Comparison of antibiotics with placebo for treatment of acute sinusitis: a meta-analysis of randomised controlled trials. Lancet Infect Dis 8:9, 2008; Hsu HE et al: Effect of pneumococcal conjugate vaccine on pneumococcal meningitis. N Eng J Med 3:360, 2009; Johnson NC, Holger JS: Pediatric acute otitis media: the case for delayed antibiotic treatment. J Emerg Med 3:23, 2007; Lee MD et al: Screening young children with a first febrile urinary tract infection for high-grade vesicoureteral reflux with renal ultrasound scanning and technetium-99m-labeled dimercaptosuccinic acid scanning. J Pediatr 6:154, 2009. Lighter J et al: Latent tuberculosis diagnosis in children by using the QuantiFERON-TB Gold In-Tube test. Pediatrics 1:123, 2009; Pais PJ et al: Delay in diagnosis in poststreptococcal glomerulonephritis. J Pediatr 4:153, 2008; Sabharwal T et al: Comparison of factors associated with coronary artery dilation only versus coronary artery aneurysms in patients with Kawasaki disease. Am J Cardiol 12:104, 2009; Tanz RR et al: Performance of a rapid antigen-detection test and throat culture in community pediatric offices: implications of management of pharyngitis. Pediatrics 2:123, 2009; Uehara R et al: Analysis of po­tential risk factors associated with nonresponse to initial intravenous immunoglobulin treatment among Kawasaki disease patients in Japan. Pediatr Infect Dis J 2:27, 2008; Whiting P et al: Rapid tests and urine sampling techniques for the diagnosis of urinary tract infection (UTI) in children under five years: a systematic review. BMC Pediatr 1:5, 2005; Williamson I et al: Topical intranasal cor­ticosteroids in 4-11 year old children with persistent bilateral otitis media with effusion in primary care: double blind randomised pla­cebo controlled trial. BMJ 339:b4984, 2009.