Can you determine the most likely diagnosis for a 55-year-old man who’s experienced a ST-segment myocardial infarction and is admitted for coronary angiography with stent placement in the left anterior descending artery? Let’s learn more about the case!
A 55-year-old man experiences a ST-segment myocardial infarction and is admitted for coronary angiography with stent placement in the left anterior descending artery. On day four of hospitalization, he has sudden sharp chest pain that radiates to his neck and shoulders. The pain is exacerbated by coughing and deep breathing. Vitals are within normal limits. Physical examination shows a restless man whose symptoms improve when sitting forward from a supine position. There is a loud rubbing sound upon cardiac auscultation when he leans forward. Lungs are clear to auscultation bilaterally. An ECG is shown below. The patient is treated with an antiplatelet drug.
Which of the following is a common adverse effect of the antiplatelet medication administered to this patient?
A. Gastric ulcers
B. Neutropenia
C. Osteoporosis
D. Skin necrosis
E. Hypotension
Scroll down for the correct answer!
The correct answer to today’s USMLE® Step 1 Question is…
A. Gastric ulcers
Correct: See Main Explanation.
Incorrect Answer Explanations
B. Neutropenia
Incorrect: Neutropenia is a rare but serious adverse effect of the ADP receptor inhibitor, ticlopidine. It prevents platelet aggregation by irreversibly blocking ADP (P2Y12) receptor and inhibiting the expression of glycoproteins IIb/IIIa on the platelet surface. Although it is indicated in managing acute coronary syndrome and coronary stenting, this patient’s symptoms indicate post-MI pericarditis, usually treated with aspirin.
C. Osteoporosis
Incorrect: Osteoporosis is a common adverse effect of heparin therapy. An anticoagulant (not antiplatelet) activates antithrombin in the coagulation pathway, which decreases the action of factor IIa (thrombin) and factor Xa. Although heparin is indicated in patients with coronary stent placement, it cannot alleviate the symptoms of pericarditis.
D. Skin necrosis
Incorrect: Skin and tissue necrosis are serious adverse effects of warfarin therapy and are thought to result from small vessel microthrombosis. Warfarin is an anticoagulant (not antiplatelet), usually administered in patients requiring chronic anticoagulation (e.g., venous thromboembolism prophylaxis and stroke prevention in atrial fibrillation). It is not indicated in the treatment of pericarditis.
E. Hypotension
Incorrect: Hypotension is a common adverse effect of phosphodiesterase inhibitors (e.g., cilostazol), which inhibit the breakdown of cyclic guanosine monophosphate in the vascular smooth muscle cells, preventing vasoconstriction. They are usually used to treat peripheral artery disease and coronary artery disease and can be combined with aspirin for secondary prevention of ischemic stroke. They are, however, not indicated in the treatment of acute pericarditis.
Main Explanation
This patient with sharp and pleuritic chest pain on the 4th day of hospitalization following an acute ST-elevation myocardial infarction, in combination with ECG findings of diffuse ST-elevation, is suggestive of peri-infarction pericarditis. It is usually managed with aspirin, which risks developing gastric ulcers.
Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) with an antiplatelet effect. It irreversibly inhibits the activity of cyclooxygenase enzymes (COX-1 and COX-2) via acetylation, thereby preventing the formation of thromboxane A2, which usually helps in platelet adhesion. It is used in several clinical situations to prevent clots from worsening or provide anti-inflammatory effects:
A dose of 325 mg is used as a loading dose to treat acute strokes and myocardial infarction. A dose of 81 mg tablets is used as the maintenance therapy
A dose of 650 mg – 1 g every 8 hours is indicated for the treatment of pericarditis, followed by gradual taper after resolution of symptoms.
Common adverse effects of its use include increased risk of bleeding and gastric ulcers.
Major Takeaway
Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) with an antiplatelet effect. It irreversibly inhibits the activity of cyclooxygenase enzymes (COX-1 and COX-2), preventing the formation of thromboxane A2. It is indicated in treating stroke, myocardial infarction, and pericarditis. Common adverse effects include an increased risk of bleeding and the formation of gastric ulcers.
Want to learn more about this topic?
Read this Osmosis Answer page: Antiplatelet medications
References
- Imazio, M., & Hoit, B. D. (2013). Post-cardiac injury syndromes. An emerging cause of pericardial diseases. International journal of cardiology, 168(2), 648-652.
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