An 11-month-old boy is brought to the emergency department due to irritability and poor fluid intake. Seven days ago, the patient developed a fever with poor appetite, and he has continued to have daily fevers. Over the past 2 days, the patient has only consumed half of the daily volume of formula he normally drinks. The patient has also been sweating while feeding. He is often irritable when awake and has been napping longer than usual. Temperature is 38.6 C (101.5 F), blood pressure is 74/38 mm Hg, pulse is 194/min, and respirations are 60/min. The patient appears irritable and is grunting. Examination shows an injected pharynx and bilateral conjunctivae. There is perianal peeling and periungual desquamation of his hands, fingers, and toes. Cardiopulmonary examination reveals an S3 gallop and diffuse, fine lung crackles bilaterally. The liver is 3 cm below the costal margin. There is edema of the bilateral lower extremities. Chest-x ray reveals pulmonary edema. Which of the following is the most likely etiology of this patient's condition?

Question

An 11-month-old boy is brought to the emergency department due to irritability and poor fluid intake.  Seven days ago, the patient developed a fever with poor appetite, and he has continued to have daily fevers.  Over the past 2 days, the patient has only consumed half of the daily volume of formula he normally drinks.  The patient has also been sweating while feeding.  He is often irritable when awake and has been napping longer than usual.  Temperature is 38.6 C (101.5 F), blood pressure is 74/38 mm Hg, pulse is 194/min, and respirations are 60/min.  The patient appears irritable and is grunting.  Examination shows an injected pharynx and bilateral conjunctivae.  There is perianal peeling and periungual desquamation of his hands, fingers, and toes.  Cardiopulmonary examination reveals an S3 gallop and diffuse, fine lung crackles bilaterally.  The liver is 3 cm below the costal margin.  There is edema of the bilateral lower extremities.  Chest-x ray reveals pulmonary edema.  Which of the following is the most likely etiology of this patient's condition?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d73f_2852_bc81_01a813433f0c_MD0003_00 This infant has prolonged fever and characteristic signs of Kawasaki disease, an acute vasculitis with potentially life-threatening cardiac sequelae. Pathophysiology of cardiac involvement relates to systemic inflammation leading to infiltration of lymphocytes and macrophages into cardiac tissues and vasculature. Complications include: Kawasaki disease Coronary artery aneurysm: severe dilatation can lead to stenosis/thrombosis and myocardial infarction Ventricular dysfunction: systemic inflammation or lymphocytic myocarditis can cause poor contractility and heart failure Pericardial effusion: cardiac tamponade may result This infant has symptoms of heart failure, including irritability, poor feeding, and diaphoresis during feeds. As seen here, pulmonary edema, lower extremity swelling, and hepatomegaly, along with tachypnea and tachycardia, occur with progressive left ventricular overload. An S3 gallop due to rapid ventricular filling is characteristic. Prolonged fevers (>14 days), delayed treatment with intravenous immunoglobulin (IVIG), and age <1 increase the risk for cardiac complications. Most aneurysms regress over time, and ventricular dysfunction typically improves with IVIG therapy. (Choice A) Arteriovenous malformation causes extracardiac left-to-right shunting, potentially leading to high-output cardiac failure from increased venous return. However, a wide pulse pressure caused by increased stroke volume is typical, and fever would not be seen. (Choice B) Bacterial endocarditis can cause acute fever and heart failure. However, a new murmur would be expected, and this patient's mucocutaneous inflammation (eg, conjunctivitis, mucositis) makes this diagnosis less likely. (Choice C) Eosinophilic myocarditis can present with fever, rash, and symptoms of heart failure. However, the rash is eczematous or urticarial, not desquamative. Moreover, pathophysiology typically involves hypersensitivity to an inciting medication, not present here. (Choice E) Acute rheumatic fever, a rare diagnosis before age <3, can present with fever and carditis. However, this patient has no other associated findings (eg, arthritis, subcutaneous nodules, erythema marginatum, chorea), and a blowing, systolic mitral regurgitation murmur due to valvulitis would be expected. Moreover, conjunctivitis and desquamation would not be seen. Educational objective: In addition to an increased risk of coronary artery aneurysms, Kawasaki disease increases risk of ventricular dysfunction due to lymphocytic myocarditis, particularly in infants. Patients can have heart failure symptoms (eg, diaphoresis with feeds) and signs (eg, hepatomegaly, pulmonary edema, S3 gallop). References: Lifetime cardiovascular management of patients with previous Kawasaki disease. (http://www.ncbi.nlm.nih.gov/pubmed/31843876) Risk factors and implications of progressive coronary dilatation in children with Kawasaki disease. (http://www.ncbi.nlm.nih.gov/pubmed/28587647)

An 11-Month-Old Boy Is Brought to the Emergency Department Due