A 2-year-old boy is brought to the emergency department due to fever and respiratory distress. A week ago the patient had rhinorrhea and nasal congestion that spontaneously resolved. For the past 3 days he has had persistent fever and has become increasingly tired. Today his breathing is labored. The patient has no chronic medical conditions and is up to date with recommended vaccinations. Temperature is 38.2 C (100.7 F). Scattered, mobile, subcentimeter lymph nodes are palpable in the anterior cervical chain bilaterally. Cardiac examination shows tachycardia, an S3 gallop, and a grade 3/6 holosystolic murmur loudest at the cardiac apex. Brachial and femoral pulses are 1+. Pulmonary examination reveals tachypnea, nasal flaring, and subcostal retractions. Scattered wheezes are present at the lung bases and persist despite bronchodilator treatment. The liver is palpated 4 cm (1.6 in) below the costal margin. Which of the following is the most likely diagnosis in this patient?

Question

A 2-year-old boy is brought to the emergency department due to fever and respiratory distress.  A week ago the patient had rhinorrhea and nasal congestion that spontaneously resolved.  For the past 3 days he has had persistent fever and has become increasingly tired.  Today his breathing is labored.  The patient has no chronic medical conditions and is up to date with recommended vaccinations.  Temperature is 38.2 C (100.7 F).  Scattered, mobile, subcentimeter lymph nodes are palpable in the anterior cervical chain bilaterally.  Cardiac examination shows tachycardia, an S3 gallop, and a grade 3/6 holosystolic murmur loudest at the cardiac apex.  Brachial and femoral pulses are 1+.  Pulmonary examination reveals tachypnea, nasal flaring, and subcostal retractions.  Scattered wheezes are present at the lung bases and persist despite bronchodilator treatment.  The liver is palpated 4 cm (1.6 in) below the costal margin.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d635_cea6_bc81_47e9450e7b5f_MD0003_00 Myocarditis is a potentially lethal disorder of the myocardium and is most commonly caused, in children, by viral infection (eg, Coxsackievirus B, adenovirus). Myocyte necrosis by direct viral injury and autoimmune inflammation results in impaired systolic and diastolic function. A viral prodrome (eg, upper respiratory infection [URI]) often precedes the illness. Patients then typically develop chest pain and respiratory distress (eg, dyspnea, tachypnea, wheezing, crackles) from acute left heart failure and pulmonary edema. Dilated cardiomyopathy with mitral regurgitation can cause an S3 gallop and holosystolic murmur, as seen in this patient. In addition, hepatomegaly is a sign of passive congestion from right heart failure. Initial workup includes ECG, chest x-ray, and echocardiogram. Chest x-ray typically reveals cardiomegaly (cardiothoracic ratio >50%), and echocardiogram often shows global hypokinesis with decreased ejection fraction. Although endomyocardial biopsy is the diagnostic gold standard, treatment (eg, diuretics, inotropes) is typically initiated based on clinical suspicion. In addition, patients should be monitored in the intensive care unit due to risk of shock and fatal arrhythmias. Chest x-ray (Choice A) Acute rheumatic fever can cause myocarditis but typically presents with fever and arthritis weeks after untreated group A streptococcal pharyngitis. This patient's rhinorrhea and congestion are more likely due to a virus. (Choice B) A viral URI can trigger an asthma exacerbation. However, asthma typically improves with bronchodilation; this patient's S3 gallop and hepatomegaly make myocarditis more likely. (Choice C) Community-acquired pneumonia can follow a URI and present with fever and respiratory distress. However, signs of heart failure (eg, gallop, murmur, hepatomegaly) would not be expected. (Choice D) Myocarditis can occur in the acute phase of Kawasaki disease. However, Kawasaki disease requires ≥5 days of fever and ≥4 clinical criteria (rash, lymphadenopathy >1.5 cm, conjunctivitis, mucosal changes, extremity changes) to establish the diagnosis. Kawasaki disease (Choice E) Viral hepatitis can cause hepatomegaly but would not explain this patient's respiratory distress. Educational objective: Myocarditis is most commonly caused, in children, by viral infection and typically presents following a viral prodrome with signs of heart failure (eg, respiratory distress, murmur, cardiomegaly, hepatomegaly). References: The evolving approach to paediatric myocarditis: a review of the current literature. (http://www.ncbi.nlm.nih.gov/pubmed/21272427) Update on myocarditis in children. (http://www.ncbi.nlm.nih.gov/pubmed/20414115)

A 2-Year-Old Boy Is Brought to the Emergency Department Due