Pediatric Examination and Board Review (189 page)

(B) EIA on serum for
B burgdorferi
IgG antibody

(C) PCR on serum to detect
B burgdorferi
DNA

(D) urine antigen detection for
B burgdorferi

(E) culture of blood for
B burgdorferi

17.
Of the following, the most appropriate antibiotic for treatment of Lyme arthritis in the 10-year-old girl is

(A) azithromycin

(B) ceftriaxone

(C) amoxicillin

(D) trimethoprim-sulfamethoxazole

(E) doxycycline

ANSWERS

1.
(D)
S pneumoniae
is the most common cause of primary peritonitis in children with no underlying immune or anatomic defect. Less common causes include other gram-positive organisms (
S aureus
, group B streptococcus) and a variety of gramnegative organisms such as
E coli
and
Klebsiella
species.
N meningitidis
and
N gonorrhoeae
primary peritonitis has also been reported (
Table 106-1
).

TABLE 106-1
Classification and Etiology of Peritonitis in Children

Abbreviations: CAPD, continuous ambulatory peritoneal dialysis; CoNS, coagulase negative staphylococci; GBS, Group B streptococcus; GNB, gram-negative bacilli; Spn,
Streptococcus pneumoniae
; VP, ventriculoperitoneal.

2.
(D)
The serum opsonizing activity of children with nephrotic syndrome is decreased. Children with nephrotic syndrome are at greatest risk for pneumococcal sepsis and peritonitis when in relapse and spilling large amounts of protein, which includes factor B of the alternative complement pathway. Children with nephrotic syndrome can also have low serum IgG levels.

3.
(E)
Prepubertal children with gonococcal vaginitis can develop peritonitis. The diagnosis can be confirmed by culture of the vagina for
N gonorrhoeae
. In this circumstance an evaluation for sexual abuse must be undertaken.

4.
(D)
Gram-positive organisms including
S epidermidis
and
S aureus
account for 50% of episodes. Gram-negative organisms account for 20% and fungal peritonitis occurs in 2% (
Table 106-1
). The classic triad of peritonitis in CAPD is fever, abdominal pain, and cloudy peritoneal dialysis fluid.

5.
(D)
There is no one historical item or diagnostic test that will identify all children with occult bacteremia. Fever higher than 103.1°F (39.5°C), age 3-36 months, and a leukocyte count more than 15,000/mm
³
increase the risk of occult bacteremia. The most common etiology of occult bacteremia is
S pneumoniae
.
H influenzae
type b was the second most common cause but has been virtually eliminated with the routine immunization of infants with
H influenzae
type b conjugate vaccine.
N meningitidis
infection can also cause occult bacteremia.

6.
(B)
Late-onset disease caused by
S agalactiae
should be considered as a cause of bacteremia without focality in infants younger than 3 months of age. Meningitis is the most serious complication that can complicate bacteremia, but osteomyelitis, arthritis, cellulitis, or adenitis can occur. Some of these infections without focality have occurred in very low birthweight infants after a prolonged hospitalization. This clinical manifestation of group B streptococcus has been termed very late-onset infection.

7.
(A)
The child fulfills the “classic” diagnostic criteria for Kawasaki disease with fever persisting at least 5 days plus the presence of at least 4 of 5 designated clinical criteria. These include bilateral bulbar conjunctival injection, changes of the lips and oral cavity, erythema and swelling of the hands and feet, and an erythematous rash (see
Figure 106-2
). One feature the child did not have was one or more enlarged lymph nodes larger than 1.5 cm in diameter.

In the presence of four or more criteria, the diagnosis of Kawasaki disease can be made on day 4 of illness. The diagnosis should be considered in a young child with fever 5 days or longer and any of the principal clinical features of the disease. An algorithm has been developed by the American Heart Association (AHA) and American Academy of Pediatrics (AAP) to aid clinicians in deciding which patients with fever and fewer than four classic criteria should undergo echocardiography and receive salicylate and IVIG treatment for Kawasaki disease. This includes a combination of assessing whether the patient’s characteristics are consistent with Kawasaki disease and assessing laboratory tests including CRP and ESR.

Treatment of Kawasaki disease includes IGIV 2 g/kg given as a single infusion plus an antiinflammatory dose of aspirin, 80-100 mg/kg per day in four divided doses. Retreatment with IGIV is recommended for patients with persistent fever for 48 hours after the initial infusion or recurrence of fever after an initial period of being afebrile for 48 hours or less.

FIGURE 106-2.
Kawasaki disease. Cherry-red lips with hemorrhagic fissures, in a young boy with prolonged high fever. This child also had a generalized morbilliform eruption, injected conjunctivae, and a “strawberry” tongue (not shown). Note erythema and edema of finger tips. (Reproduced, with permission, from Wolff K, Johnson RA. Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 6th ed. New York: McGraw-Hill; 2009: Fig. 14-44.)

8.
(B)
Many infectious agents are associated with the development of erythema multiforme minor (involvement of no more than one mucosal surface). However,
M pneumoniae
is the most convincingly demonstrated cause of erythema multiforme and Stevens-Johnson syndrome.

9.
(E)
Brucellosis is prevalent in the Mediterranean basin and the Indian subcontinent as well as Mexico and Central and South America. Malaria occurs in tropical climates, and salmonellosis in the form of typhoid fever usually is related to travel in a developing country in the 6 weeks before illness onset.
Bartonella henselae
causing catscratch disease occurs sporadically throughout the United States.
B bacilliformis
occurs in a restricted geographic region in the Andes Mountains in western South America. The acute form is a febrile illness with high mortality and is called Oroya fever. This is a bacteremic illness resulting in severe hemolytic anemia and transient immune suppression.

10.
(A)
The definition of FUO includes a minimum of 14 days of daily temperature of 100.9°F (38.3°C) or higher with no apparent cause, after performance of repeated physical examinations and screening laboratory tests. Infections account for more than a third of cases of FUO, and in general are common infections with an uncommon presentation. In a recent series of children with FUO, Epstein-Barr virus infection, vertebral and pelvic osteomyelitis, catscratch disease and urinary tract infection were the most common infections described.

11.
(B)
The likelihood of establishing a diagnosis in a child with FUO is low in patients with a normal ESR and hemoglobin value.

12.
(D)
Other disorders causing periodic, recurrent, or episodic fevers include relapsing fever caused by
Borrelia recurrentis
and familial Mediterranean fever. Kikuchi-Fujimoto disease is a histiocytic necrotizing lymphadenitis and is in the differential diagnosis of regional or generalized lymphadenopathy that may present as an FUO but not as a periodic fever syndrome.

13.
(D)
Many infectious and noninfectious diseases cause generalized lymphadenopathy. Both
Salmonella typhi
and
Y enterocolitica
can cause mesenteric lymphadenitis.
S typhi
can cause hepatosplenomegaly and generalized lymphadenopathy, although the lymphadenopathy of
Y enterocolitica
is seldom generalized. Generalized lymphadenopathy can occur in association with
E chaffeensis,
which causes human monocytic ehrlichiosis, a tick-borne disease.

14.
(E)
The 7-year-old fulfills the Jones criteria for the diagnosis of acute rheumatic fever with one major criterion, polyarthritis, found in approximately 75% of cases and 2 minor criteria (fever and accelerated ESR) along with supporting evidence of antecedent group A streptococcus infection.
Figure 106-1
shows a Gram stain of a broth culture obtained from a beta-hemolytic colony from a blood agar plate revealing gram-positive cocci in chains identified as
S pyogenes
(group A streptococcus). Other major criteria include carditis (50-60% of cases), chorea (10-15% of cases), erythema marginatum (<3% of cases), and subcutaneous nodules (≤1% of cases).

15.
(C)
The neonate described above with rash and splenomegaly also has nephrotic syndrome and anemia. Nephrotic syndrome occurs in infants with congenital syphilis and is caused by immune complex disease. The negative RPR may be secondary to the prozone phenomenon. This results from excess antibody concentration that inhibits the formation of the antigen-antibody complex that is needed for flocculation. Diluting the same serum and retesting will result is a positive test. The clinical laboratory should be alerted to this possibility. A specific treponemal test such as the FTA-ABS or TP-PA tests should also be positive. Toxoplasmosis is less likely with the normal eye and CSF examinations, and HIV is less likely with the negative HIV EIA. Infants with symptomatic congenital CMV infection will often have neurologic sequelae, including microcephaly, hypotonia, hearing loss, and seizures.

16.
(B)
The EIA used to detect antibodies against
B burgdorferi
is usually negative in patients with early localized disease, such as a single erythema migrans lesion. Some patients who are treated early with an antimicrobial agent never develop antibodies against
B burgdorferi
. Most patients with early disseminated Lyme disease and all patients with late disseminated disease (arthritis is the most common manifestation) have a strong IgG antibody response to
B burgdorferi
.

17.
(E)
The antibiotic of choice for late disseminated disease manifesting as Lyme arthritis is doxycycline for children 8 years of age or older or amoxicillin for children younger than 8 years of age. The recommended duration of therapy is 28 days, compared with 14-21 days for early localized disease. Meningitis, or other CNS disease and carditis, with third-degree heart block should be treated with ceftriaxone for 14-28 days.

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