Pediatric Examination and Board Review (178 page)

(A) unrecognized congenital heart disease

(B) prior rheumatic heart disease

(C) IV drug use

(D) immunodeficiency with an underlying phagocyte function disorder

(E) HIV infection

12.
A 3-week-old female infant was born to a mother with a history of IV drug abuse. The mother had serologic testing for HIV, RPR, and HBsAg during the second trimester of pregnancy. All results were negative. The infant now presents at 3 weeks of age with a diffuse vesiculobullous rash that involves the palms and soles. The diagnostic test that will most likely reveal the etiology of the rash is

(A) culture of vesicle scrapings for HSV

(B) direct fluorescent antibody staining of vesicle scraping for varicella-zoster-virus

(C) RPR and FTA-ABS tests for syphilis

(D) Gram stain and bacterial culture of vesicle fluid

(E) urine culture for CMV

13.
A 10-day-old term infant girl presents to your office with eyelid swelling, erythema, and mucopurulent drainage from the left eye. A culture of the conjunctiva does not grow
N gonorrhoeae
or other bacterial pathogens. What important historical factor in the mother will help best in determining the etiology of the newborn’s conjunctivitis?

(A) sexual history of the parents

(B) medication history

(C) surgical history

(D) history of prior miscarriages

(E) history of contact with other children in family with conjunctivitis

14.
The mother of the 10-day-old infant with conjunctivitis should also have testing to determine possible infection with

(A) HSV

(B) toxoplasmosis

(C) hepatitis B virus

(D) CMV

(E) HIV

15.
The indigenous bacterial flora of the gut are important in the pathogenesis of infection caused by pathogenic bacteria. Antimicrobial therapy can result in diarrhea with alterations in the colonic microflora. Antimicrobial therapy can lead to diarrhea with the overgrowth of which of the following bacteria?

(A)
Campylobacter jejuni

(B) enterotoxigenic
E coli

(C)
Aeromonas hydrophila

(D)
Clostridium difficile

(E)
Yersinia enterocolitica

16.
A 7-year-old boy with newly diagnosed AML has recently completed induction chemotherapy. He develops fever, neutropenia (absolute neutrophil count of 100 cells/mm
³
), and shock. All of the following bacteria are likely pathogens except

(A)
S pyogenes

(B)
S aureus

(C)
S epidermidis

(D)
P aeruginosa

(E)
E coli

17.
An 18-year-old girl with congenital asplenia associated with congenital heart disease develops fever to 104°F (40°C) associated with a faint maculopapular rash. The child is at high risk for fulminant infection with all of the following agents except

(A)
H influenzae
type b

(B)
N meningitidis

(C)
P aeruginosa

(D)
S pneumoniae

(E)
Salmonella typhimurium

18.
A 4-year-old boy with ALL develops fever to 103°F (39.4°C). He also has neutropenia with an absolute neutrophil count of 200 cells/mm
³
. An appropriate antimicrobial regimen for initial empirical therapy is

(A) aztreonam

(B) ceftriaxone

(C) cefazolin and gentamicin

(D) trimethoprim-sulfamethoxazole and vancomycin

(E) ceftazidime

19.
Aspergillus can cause invasive pulmonary infection in children with underlying medical problems. Of the following patients, the one most likely to develop invasive pulmonary aspergillosis is

(A) a 19-year-old adolescent boy with ALL in relapse with fever and neutropenia

(B) an 8-year-old girl with HIV infection and pneumonia and a CD4 percentage of 20%

(C) a 12-year-old girl with cystic fibrosis, new infiltrates on chest radiographs, and hypoxia

(D) a 4-year-old boy with common variable immunodeficiency who develops pneumonia

(E) a 5-year-old girl with terminal complement component deficiency

ANSWERS

1.
(A)
Obtaining a CBC, differential, and platelet count provides a great deal of information; the results give information regarding leukocytosis, leukopenia (lymphopenia, neutropenia), leukocyte morphology, the presence of Howell-Jolly bodies, anemia, and thrombocytopenia.

2.
(B)
Among adolescents in the 13-19-year age group, the proportion of cases of HIV/AIDS in girls in 2007 was about a third that in boys (
Table 101-1
). The major route of transmission in adolescent girls is heterosexual transmission. Most HIV-infected adolescents are asymptomatic and not aware they are infected. In 2007 among adolescents 13-19 years of age diagnosed with AIDS, 40% were female.

3.
(E)
Acute HIV infection should be considered in any adolescent with a mononucleosis-like illness. Fever, fatigue, pharyngitis, lymphadenopathy, mucocutaneous ulcers, and rash are common signs and symptoms seen with acute HIV infection. Initial HIV antibody tests are often negative, which emphasizes the importance of using nucleic acid amplification tests that can detect HIV-1 RNA for diagnosis.

TABLE 101-1
Distribution of Cases of HIV/AIDS Cases Reported Among Adolescents and Young Adults by Sex and Age Groups
*

*
From 34 states with confidential name-based HIV infection reporting in 2007.
Data from U.S. Centers for Disease Control and Prevention.

4.
(D)
P jiroveci
most commonly occurs in HIVinfected children 3-6 months of age. Nevertheless, in adolescents
Pneumocystis
pneumonia is still a more common AIDS-defining diagnosis than
Candida
, CMV, or
M avium
complex (MAC) disease.

5.
(A)
Epidemics of PCP have occurred in malnourished infants and children, as well as premature infants. With HIV infection, the risk of PCP is related to the viral-induced suppression of cellmediated immunity. The decision to administer PCP prophylaxis is based on the total CD4 lymphocyte count and percentage.

6.
(C)
Protein calorie malnutrition is a condition that can predispose to recurrent infections. Cellular immunity is important for protection against enteric bacteria.

7.
(A)
With malnutrition associated with protein/energy deficiency, there are immune deficits involving cellular immunity and T-cell function. IgA and E levels may be decreased.

8.
(A)
The pathogenesis of fever involves cytokinestimulation of the preoptic area of the hypothalamus (thermoregulatory center), which leads to the production of prostaglandin E2. This molecule is thought to activate thermoregulatory neurons to raise the thermostat set point. Then peripheral mechanisms are activated that lead to vasoconstriction and muscle contraction, which result in the generation of fever. Also certain areas in the cerebral cortex are stimulated to promote behavioral changes designed to help control temperature.

9.
(B)
There is evidence that fever is more beneficial than harmful to the host. High temperature interferes with the replication and virulence of certain pathogens. Fever represents a regulatory mechanism to reduce cytokine activation in the acute inflammatory response. Controversy exists about whether febrile episodes should be treated. A short course of an antipyretic drug has low risk for toxicity, and most of the appropriate antipyretic drugs also have analgesic properties.

10.
(E)
Immunity to
S pneumoniae
is related to the production of type-specific humoral immunity. Development of type-specific antibodies against the capsular polysaccharide correlates with immunity to that specific serotype. Children with deficiency of the classical pathway of complement such as C2 deficiency are at increased risk for invasive infections caused by
S pneumoniae
. IgG subclass deficiencies are not associated with an increased risk for invasive pneumococcal infections.

11.
(C)
In this previously healthy adolescent, IV drug use would be the most likely risk factor for development of right-sided endocarditis. Other risk factors for right-sided endocarditis include the presence of pacemakers, wires, and long-term central venous catheterization.

12.
(C)
The description of the rash is most characteristic of congenital syphilis, even though the RPR drawn on the mother in the second trimester was nonreactive. A history of IV drug use should raise the suspicion of syphilis as well as HIV and hepatitis B infection. Another important risk factor for vertical transmission of syphilis is lack of prenatal care.

13.
(A)
The most likely pathogen in this case of mucopurulent conjunctivitis is
C trachomatis
, a sexually transmitted disease (STD). Many men and women infected with
C trachomatis
are either asymptomatic or mildly symptomatic so a history of sexual activity is important to obtain. Symptoms of conjunctivitis in the newborn infant due to
C trachomatis
usually present within 5-14 days after birth but can be seen as late as 60 days.

14.
(E)
In this clinical setting, the infant most likely has infection with
C trachomatis.
Individuals who have an STD such as
C trachomatis
or
N gonorrhoeae
should also be evaluated for HIV infection.

15.
(D)
Diarrhea can occur during therapy with many different antimicrobial agents. Antimicrobialassociated diarrhea can result from either changes in small bowel peristalsis or from alteration in the normal flora found in the intestine. A good example of the latter is overgrowth in the colon of
C difficile
.

16.
(C)
Patients with fever and neutropenia can develop infections caused by coagulase-negative staphylococci such as
S epidermidis
. However, this is a more indolent infection, and a short delay in administration of specific antimicrobial therapy has not been shown to be detrimental to the patient’s outcome. The other bacteria listed can all cause fulminant infection resulting in death.

17.
(C)
Patients with asplenia are at increased risk for overwhelming life-threatening infections. The most common organism involved is
S pneumoniae,
but other encapsulated bacteria can cause fulminant infections. Fulminant septicemia has also been reported in asplenic patients caused by
Capnocytophaga canimorsus
. This species is part of the normal mouth flora of dogs.

18.
(E)
A number of studies have shown no differences between monotherapy and multiple drug therapy for empirical treatment of uncomplicated episodes of fever in neutropenic patients. A third- or fourthgeneration cephalosporin (ceftazidime or cefepime) or a carbapenem (imipenem-cilastin or meropenem) may also be used. The other antibiotic regimens listed above except gentamicin do not have appreciable activity against
P aeruginosa
.