USMLE Step 3 - Question 21

A 42 year old female with no significant past medical history presents to the emergency department with hemoptysis of acute onset. She has noted recent dyspnea on exertion now to the point where she can only walk ½ blocks before having to rest. She denies chest pain. Her temperature is 37.0 C, blood pressure 110/60, heart rate 100, respirations 20, and oxygen saturation 95% on room air. Physical examination reveals normal lung sounds, an irregularly irregular rhythm, a II/IV early diastolic murmur heard best at the cardiac apex, and 1+ lower extremity pitting edema. Laboratory studies are normal. ECG shows sinus tachycardia and left atrial enlargement. Which of the following is causing this patient’s symptoms?

A. Mitral valve stenosis

B. Mitral valve prolapse

C. Mitral valve regurgitation

D. Aortic valve stenosis

E. Aortic valve regurgitation

This patient has mitral valve stenosis which results in a uniquely shaped, low-pitched diastolic murmur best heard at the cardiac apex. The opening of the mitral valve produces an "opening snap" due to the high left atrial pressures, which is immediately followed by a decrescendo murmur as blood flows passively from the left atrium to the left ventricle through the stenosed mitral valve creating turbulence. Symptoms include congestive heart failure (dyspnea on exertion and lower extremity edema), symptoms of atrial fibrillation (dizziness, palpitations, or stoke) and on occasion hemoptysis (remember mitral stenosis should always be in your differential diagnosis for hemoptysis). The hemoptysis occurs due to high left atrial pressures transmitting the pressure to the bronchial veins which can rupture. Remember that the most common cause by far of mitral valve stenosis is rheumatic valvular heart disease (from prior rheumatic fever). The best treatment is mitral valve balloon valvuloplasty. Sometimes mitral valve surgical repair or replacement is needed.