USMLE PRACTICE QUESTION #97
TOPIC: Cardiac Pathology
Today’s question will test your understanding of a high-yield cardiology concept.
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A 65-year-old man with a history of hypertension and hyperlipidemia presents to his primary care physician for a routine follow-up visit. He denies any chest pain, shortness of breath, or palpitations. He does mention that he has a sense of fatigue more often than usual as of late. His vital signs include a temperature 98.6°F (37°C), pulse of 68/minute, respirations of 18/minute, blood pressure of 130/85 mmHg, and oxygen saturation 98% on room air. Physical examination reveals a prominent S2 sound, and a harsh, crescendo-decrescendo systolic murmur best heard in the second right intercostal space that radiates to the neck. Which of the following cardiac murmurs is most consistent with this patient's presentation?
A) Aortic regurgitation
B) Aortic stenosis
C) Mitral regurgitation
D) Mitral stenosis
E) Pulmonary regurgitation
F) Pulmonary stenosis
G) Tricuspid regurgitation
Detailed Breakdown of Answers + Correct Answer Below ⏬
ANSWER + QUESTION BREAKDOWN
The MENTAL MODEL used to answer this question comes from our detailed test-taking skills masterclass (check it out if you want to elevate your skills). Here’s how to think through this question:
Step 1. Read the last line to get to the heart of the question: “Which of the following cardiac murmurs is most consistent with this patient's presentation?”
Step 2: Is this a first-, second-, or third-order question?
Answer: 1st order. 1st: Identify the murmur
Step 3: Read the vignette carefully and ask yourself: “Based on the given findings, which murmur is likely present?”
Step 4. Look at the answer choices and select the option most closely resembling your final thought from “Step 3” above.
GENERAL ANALYSIS
This vignette presents a 65-year-old man with a history of hypertension and hyperlipidemia who is asymptomatic except for increasing fatigue. His physical examination reveals a prominent S2 and a harsh, crescendo-decrescendo systolic murmur best heard in the second right intercostal space that radiates to the neck. These findings are highly suggestive of aortic stenosis.
ANSWER CHOICES:
CHOICE A: Aortic regurgitation
Explanation: Aortic regurgitation is characterized by the backflow of blood from the aorta into the left ventricle during diastole due to an incompetent aortic valve. This is characterized by a decrescendo early diastolic murmur, best heard at the left sternal border.
CHOICE B: Aortic stenosis
Explanation: The classic murmur of aortic stenosis is a crescendo-decrescendo systolic murmur best heard at the second right intercostal space (aortic area) and often radiates to the carotid arteries. Other features may include a delayed carotid upstroke and reduced or absent S2 in severe cases.
CHOICE C: Russell bodies
Explanation: Mitral regurgitation involves backflow of blood from the left ventricle into the left atrium during systole due to an incompetent mitral valve. This is typically best heard at the cardiac apex and radiates to the axilla.
CHOICE D: Mitral regurgitation
Explanation: Mitral stenosis causes obstruction to blood flow from the left atrium to the left ventricle during diastole due to narrowing of the mitral valve. This is characterized by a low-pitched, rumbling mid-diastolic murmur, often accompanied by an opening snap.
CHOICE E: Pulmonary regurgitation
Explanation: Pulmonary regurgitation involves backflow of blood from the pulmonary artery into the right ventricle during diastole. This is characterized by a decrescendo diastolic murmur, best heard over the left upper sternal border.
CHOICE F: Pulmonary stenosis
Explanation: Pulmonary stenosis involves narrowing of the pulmonary valve, causing turbulent blood flow during systole as blood exits the right ventricle into the pulmonary artery. This is characterized by a crescendo-decrescendo systolic murmur, best heard over the left upper sternal border and radiates toward the left shoulder or clavicle.
CHOICE G: Tricuspid regurgitation
Explanation: Tricuspid regurgitation involves backflow of blood from the right ventricle into the right atrium during systole due to an incompetent tricuspid valve. This is characterized by a holosystolic murmur that increases with inspiration (Carvallo’s sign), best heard at the lower left sternal border.
FINAL VERDICT…
The patient’s clinical presentation—fatigue, prominent S2 sound, and a harsh crescendo-decrescendo systolic murmur best heard in the second right intercostal space radiating to his neck—is classic for aortic stenosis (AS).
AS occurs when there is narrowing of the aortic valve, often due to calcification in older adults or congenital bicuspid valves in younger patients. The turbulent blood flow across this narrowed valve creates a characteristic ejection-type systolic murmur that peaks in midsystole and radiates to nearby structures such as the carotid arteries.
Additional findings that may be seen in severe AS include:
Diminished or absent S2
Delayed carotid upstroke
Left ventricular hypertrophy
The elevated risk factors for AS include age-related calcification, hypertension, and hyperlipidemia—conditions that are present in this patient. Thus, based on both clinical findings and auscultatory characteristics, AS is most consistent with this patient's presentation.
CORRECT ANSWER: B) Aortic stenosis
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That’s it for question 97!
See ya tomorrow 👋