A 42-year-old woman is brought to the hospital due to right-sided weakness and difficulty speaking. She has a longstanding history of a diastolic murmur, but her medical follow-up has been poor. She does not use tobacco, alcohol, or illicit drugs. A CT scan of the brain reveals a large ischemic stroke involving the left middle cerebral artery distribution. The patient dies 2 days later due to progressive neurologic deterioration. At autopsy, exploration of the left atrium shows diffuse fibrous thickening and distortion of the mitral valve leaflets, commissural fusion at the leaflet edges, and narrowing of the mitral valve orifice. This finding is most likely the result of which of the following conditions?

Question

A 42-year-old woman is brought to the hospital due to right-sided weakness and difficulty speaking.  She has a longstanding history of a diastolic murmur, but her medical follow-up has been poor.  She does not use tobacco, alcohol, or illicit drugs.  A CT scan of the brain reveals a large ischemic stroke involving the left middle cerebral artery distribution.  The patient dies 2 days later due to progressive neurologic deterioration.  At autopsy, exploration of the left atrium shows diffuse fibrous thickening and distortion of the mitral valve leaflets, commissural fusion at the leaflet edges, and narrowing of the mitral valve orifice.  This finding is most likely the result of which of the following conditions?

Quizplus · Accepted Answer

This patient's presentation suggests mitral stenosis (MS) due to rheumatic heart disease. Fibrous thickening and fusion of the valve leaflets in chronic rheumatic heart disease following acute rheumatic fever is the most common cause of MS, accounting for up to 99% of cases. There is often a latency period of 10-20 years between the initial episode of rheumatic fever and symptomatic MS, with most patients manifesting during the fourth or fifth decade of life. Mitral stenosis can cause atrial enlargement, which may lead to atrial fibrillation and/or atrial mural thromboses. Thrombi dislodged from the wall of the left atrium may later cause an embolic stroke, which likely occurred in this patient. Cardiac auscultation in mitral stenosis often reveals a loud first heart sound (S1), an early diastolic sound (opening snap), followed by a mid-diastolic murmur from turbulent flow across the mitral valve. (Choice A) Congenital endocardial cushion defects can result in mitral regurgitation. However, congenital mitral valve stenosis is rare and untreated newborns and infants typically have a grim prognosis. (Choice B) Degenerative calcific deposits most commonly develop in the mitral valve annulus in women over age 60 and generally do not impair valve function. This patient's autopsy did not show any peripherally located nodular calcific deposits. (Choice C) Embolization of vegetations due to infective endocarditis can cause a stroke or septic infarct resulting in a brain abscess. However, infective endocarditis is usually associated with large friable vegetations on the valve cusps along with destruction (rather than fibrosis) of the valve leaflets. (Choice D) Tertiary syphilis may result in aortitis, aortic aneurysm, and/or aortic regurgitation. Mitral valve lesions are not commonly observed. (Choice F) Although cardiac involvement is uncommon in rheumatoid arthritis, patients can develop pericarditis and myocarditis. Rheumatoid nodules can also develop in the cardiac tissues (including valvular structures), but these are rarely symptomatic. (Choice G) Rupture of papillary muscle (whether due to bacterial endocarditis, a connective tissue disease, or myocardial infarction) leads to prolapse of the valve leaflets and mitral regurgitation (holosystolic or early systolic murmur). Educational objective: Rheumatic mitral stenosis is characterized by diffuse fibrous thickening and distortion of the mitral valve leaflets along with commissural fusion at the leaflet edges. Patients often present with a diastolic murmur, dyspnea, and fatigue and are at increased risk of atrial fibrillation and thromboembolism (eg, stroke).

A 42-Year-Old Woman Is Brought to the Hospital Due to Right-Sided