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The answer is d. Langerhans cell histiocytosis is a multisystem disorder with a variable presentation. The skeleton is the most commonly affected site; osteolytic lesions are most often seen in the skull (Fig. 67.1). Chronically infected, draining ears are a frequent feature and associated with destruction of the mastoids. Skin involvement may be manifested as seborrheic dermatitis of the scalp or diaper area or as a petechial rash, even in the absence of thrombocytopenia. Localized or generalized lymphadenopathy with hepatosplenomegaly is also common. Infants with pulmonary disease and multiple infiltrates present with respiratory distress and progressive respiratory failure. Hypothalamic and pituitary dysfunction may result in growth retardation and diabetes insipidus, which may present as irritability, dehydration, and hypernatremia. Systemic manifestations include fever, weight loss, irritability, and failure to thrive. Skeletal survey, tissue biopsy, chest radiography, a determination of the serum sodium level and urine osmolality, and a detailed evaluation of all organ systems are necessary to establish the diagnosis and plan therapy. Multisystem involvement requires systemic chemotherapy. The prognosis in infants with multisystem disease is poor.

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The answer is a. Acute rheumatic fever is difficult to diagnose, given that no single test or clinical sign confirms the diagnosis. The Jones criteria are helpful in making the diagnosis. The presence of erythema marginatum (Fig. 67.2), a lesion characterized by a serpiginous appearance and blanching in the middle, is one of the major criteria for the diagnosis of rheumatic fever. It often occurs in patients with carditis. The other major criteria include carditis, migratory polyarthritis, chorea, and subcutaneous nodules. The minor criteria include fever, arthralgia, elevated acute phase reactants (elevated sedimentation rate, increased C-reactive protein), and a prolonged PR interval on the electrocardiogram. The presence of two major criteria or of one major and two minor criteria with evidence of streptococcal infection strongly suggests rheumatic fever. However, when a child presents with unexplained chorea or carditis, the diagnosis of rheumatic fever should be considered, even if the criteria are not met. All patients with acute rheumatic fever should be treated for group A streptococcal infection. Immunoglobulin therapy is not indicated for the child in question. Corticosteroid therapy is indicated for patients with moderate to severe carditis. Pericardiocentesis is indicated if evidence of pericardial effusion and tamponade is present.

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The answer is b. Henoch-Schönlein purpura is the most common cause of nonthrombocytopenic purpura in children. The etiology is unknown. Abdominal pain is usually secondary to vasculitis of the gastrointestinal tract and may mimic acute abdomen. Intussusception may occur occasionally. Scrotal edema and tenderness may mimic acute torsion of a testis. Renal involvement, in the form of hematuria, occurs in 25% to 50% of patients. Therapy with IV steroids is usually reserved for life-threatening intestinal and central nervous system complications. The diagnosis is based on the clinical features; routine laboratory tests are not necessary, and bone marrow aspiration is not indicated.

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The answer is a. Marfan syndrome is inherited in an autosomal-dominant pattern, but nearly 30% of cases are new mutations. Because the inheritance is autosomal-dominant, the chance that an offspring will be affected is 50%. Slit-lamp examination may reveal lens dislocation and iridodonesis. Morbidity is usually caused by cardiovascular defects, including aortic root dilatation, and mitral valve prolapse. Propranolol or atenolol may be used therapeutically to reduce cardiovascular morbidity. The cyanide nitroprusside test or specific amino acid assays can be performed to differentiate Marfan syndrome from homocystinuria.

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The answer is e. Kawasaki disease is an acute febrile vasculitis. Coronary artery dilatation and aneurysms are the most feared complications of this syndrome and occur in approximately 20% of untreated individuals. The diagnosis of Kawasaki disease is made clinically on the basis of diagnostic criteria. Adverse reactions to measlesmumpsrubella vaccine in the form of fever and rash classically develop 10 to 14 days after vaccination. Currently, corticosteroid therapy is not given initially to patients with suspected Kawasaki syndrome. Given the clinical picture, the next logical step is to obtain an echocardiogram to examine the coronary arteries and myocardial function. Depending on the child’s appearance, a lumbar puncture may be appropriate. Children
with Kawasaki syndrome can be so irritable that meningitis cannot be ruled out with confidence. In this instance, a lumbar puncture and empiric antimicrobial therapy are certainly warranted.