1. A 65-year-old man with a history of hypertension and diabetes

mellitus presents to the emergency department with chest pain,

dyspnea, and diaphoresis. He is diagnosed with an acute myocardial

infarction (AMI) and is given thrombolytic therapy. Which of the

following statements best describes the pathophysiology of AMI?

a) The coronary arteries are narrowed by atherosclerosis and

become occluded by a thrombus, resulting in ischemia and necrosis

of the myocardium.

b) The coronary arteries are dilated by vasospasm and become

obstructed by a plaque, resulting in hypoxia and apoptosis of the

myocardium.

c) The coronary arteries are inflamed by infection and become

ruptured by an aneurysm, resulting in hemorrhage and infarction of

the myocardium.

d) The coronary arteries are calcified by aging and become eroded

by ulceration, resulting in perforation and abscess of the

myocardium.

*Answer: a) The coronary arteries are narrowed by atherosclerosis

and become occluded by a thrombus, resulting in ischemia and

necrosis of the myocardium.*

Rationale: Atherosclerosis is the most common cause of coronary

artery disease, which leads to AMI. Atherosclerosis is the

accumulation of lipids, fibrous tissue, calcium, and inflammatory

cells in the arterial wall, forming plaques that reduce the lumen

diameter and blood flow. A thrombus is a blood clot that forms on a

plaque due to platelet aggregation and activation of the coagulation

cascade. A thrombus can completely or partially block the coronary

artery, depriving the myocardium of oxygen and nutrients. Ischemia

is the inadequate blood supply to a tissue, which causes reversible

cellular injury. Necrosis is the irreversible death of cells due to

severe or prolonged ischemia.

2. A 25-year-old woman with a history of systemic lupus

erythematosus (SLE) presents to the rheumatology clinic with joint