If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 3 exam, you might want to know which questions are most often missed by test-prep takers. Check out this example from Kaplan Medical, and read an expert explanation of the answer. Also check out Also check out all posts in this series.
This month’s stumper
A 58-year-old woman comes to the emergency department with chest pain that has been going on for the past 30 minutes. The pain truly frightened her because she has a history of coronary artery disease (CAD) and underwent coronary angiography with angioplasty and stent placement the previous year.
The pain is on the left side of her sternum. It does not alter in quality or intensity when she moves in bed to change position or with breathing. Her current medications are aspirin, metoprolol, lisinopril, clopidogrel and atorvastatin. On physical examination, there is chest-wall tenderness to palpation at the same spot that initially hurt her; when you press on that area, you can reproduce the pain that brought her to the hospital. EKG shows Q waves in leads II, III, and aVF.
These are unchanged compared to her previous EKG. She has a history of hypertension, diabetes and hyperlipidemia. Her mother died of a myocardial infarction at the same age she is now. She was a smoker until she had her stent placed last year.
Which of the following is the most appropriate management of this patient?
A. Enoxaparin.
B. Enoxaparin and tirofiban.
C. Enoxaparin, tirofiban, and angiography.
D. Ibuprofen and reassurance.
E. Thrombolytics.
The correct answer is D.
Kaplan Medical explains why
The patient has costochondritis. This pain is clearly reproducible by palpation and the EKG is unchanged. The point of this case is that past medical history is not as important as the current presentation of reproducible pain with clear tenderness.
Why the other answers are wrong
Choices A, B and C: Enoxaparin (choices A, B, and C) is low molecular-weight heparin, an excellent choice if this had been a non-ST segment elevation myocardial infarction. Tirofiban (choices B and C) is a glycoprotein IIb/IIIa inhibitor, appropriate if the patient were about to undergo angiography with possible angioplasty and stent placement.
Choice E: Thrombolytics are for chest pain within 12 hours of onset with ST segment elevation. Even if the pain were consistent with genuine ischemic pain, this choice would be wrong; do not give thrombolytics unless there is chest pain with either ST elevation or a new left bundle branch block. The point of this question is that the patient's history with multiple risk factors and CAD is less important than the individual presentation. The presentation is now consistent with benign chest pain, which in this case is costochondritis.
Tips to remember
When answering questions, the individual presentation is more important than the risk factors. Three features in the presentation exclude ischemia with 95 percent certainty:
- Pain that is pleuritic.
- Pain that is positional.
- Pain that is associated with chest wall tenderness.
For more prep questions on USMLE Steps 1, 2 and 3, view other posts in this series.
The AMA and Kaplan have teamed up to support you in reaching your goal of passing the USMLE® or COMLEX-USA®. If you're looking for additional resources, Kaplan provides free access to tools for pre-clinical studies, including Kaplan’s Lecture Notes series, Integrated Vignettes, Shelf Prep and more.
