An 11-year-old boy had a sore throat, no cough, tonsillar exudates, and 38.3deg C fever 3 weeks ago, and a throat culture was positive for group A b-hemolytic Streptococcus. On the follow-up examination, the child is afebrile. His pulse is 85/min, respirations are 18/min, and blood pressure is 90/50 mm Hg. On auscultation, a diastolic mitral murmur is audible, and there are diffuse rales over both lungs. Over the next 2 days, he has several episodes of atrial fibrillation accompanied by signs of acute left ventricular failure. Which of the following pathologic changes occurring in this child’s heart is most likely to be the cause of the left ventricular failure?
An 11-year-old boy had a sore throat, no cough, tonsillar exudates, and 38.3deg C fever 3 weeks ago, and a throat culture was positive for group A b-hemolytic Streptococcus. On the follow-up examination, the child is afebrile. His pulse is 85/min, respirations are 18/min, and blood pressure is 90/50 mm Hg. On auscultation, a diastolic mitral murmur is audible, and there are diffuse rales over both lungs. Over the next 2 days, he has several episodes of atrial fibrillation accompanied by signs of acute left ventricular failure. Which of the following pathologic changes occurring in this child’s heart is most likely to be the cause of the left ventricular failure?
💡 Explanation
**Core Concept**
The question requires knowledge of rheumatic fever, its cardiac manifestations, and the pathologic changes that can lead to left ventricular failure. Rheumatic fever is a complication of untreated or inadequately treated group A beta-hemolytic Streptococcus (GABHS) pharyngitis, and it can cause damage to the heart valves and heart muscle.
**Why the Correct Answer is Right**
The child in the question had rheumatic fever, as evidenced by the sore throat, tonsillar exudates, and positive throat culture for GABHS. The diastolic mitral murmur and diffuse rales over both lungs suggest mitral regurgitation and pulmonary congestion, respectively. Over the next 2 days, the child developed atrial fibrillation, which is a common arrhythmia in patients with rheumatic heart disease. The pathologic change that is most likely to be the cause of left ventricular failure in this child is Libman-Sacks endocarditis, which is a form of non-bacterial endocarditis that occurs in the setting of systemic lupus erythematosus or rheumatic fever. However, the more likely answer in this case is rheumatic carditis. Rheumatic carditis is an inflammatory process that can cause damage to the heart valves and heart muscle, leading to left ventricular failure.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the question. The question is asking about the pathologic change that is most likely to be the cause of left ventricular failure, not the cause of the child's symptoms or the diagnosis of rheumatic fever.
* **Option B:** This option is incorrect because it is not a pathologic change that is commonly associated with rheumatic fever or left ventricular failure.
* **Option D:** This option is incorrect because it is not a pathologic change that is commonly associated with rheumatic fever or left ventricular failure.
**Clinical Pearl / High-Yield Fact**
Rheumatic fever can cause significant morbidity and mortality if left untreated or inadequately treated. Early recognition and treatment of GABHS pharyngitis and rheumatic fever are crucial to prevent these complications. The Jones criteria are used to diagnose rheumatic fever, and they include major and minor criteria.
**Correct Answer: C. Rheumatic carditis**
✓ Correct Answer: D. Myocarditis
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