COMAT COMAT Pathophysiology and Disease Processes 2 — Questions and Answers
Question 1: Which pathophysiologic process underlies the conversion of stable atherosclerotic plaque to an acute coronary syndrome?
- Gradual luminal occlusion over decades
- Plaque rupture or erosion triggering thrombus formation (Correct answer)
- Coronary artery spasm without plaque
- Embolic occlusion from left atrial thrombus
Correct answer: Plaque rupture or erosion triggering thrombus formation
ACS is precipitated by disruption of an atherosclerotic plaque's fibrous cap, exposing thrombogenic material and triggering platelet aggregation and thrombus formation.
Question 2: Hyponatremia in a patient with SIADH is best explained by which mechanism?
- Renal salt wasting due to mineralocorticoid deficiency
- Excess free water retention due to inappropriate ADH secretion (Correct answer)
- Hyperglycemia causing osmotic shift of water into serum
- Pseudohyponatremia from hyperlipidemia
Correct answer: Excess free water retention due to inappropriate ADH secretion
SIADH causes inappropriate retention of free water by the kidneys, diluting serum sodium concentration despite normal or increased total body water.
Question 3: Which cell type is primarily responsible for the airway hyperresponsiveness seen in asthma?
- Neutrophils and macrophages
- Eosinophils, mast cells, and Th2 lymphocytes (Correct answer)
- CD8+ cytotoxic T cells
- Natural killer cells
Correct answer: Eosinophils, mast cells, and Th2 lymphocytes
Asthma involves a Th2-driven eosinophilic inflammation with mast cell degranulation releasing histamine and leukotrienes, causing bronchoconstriction and airway hyperresponsiveness.
Question 4: Deep venous thrombosis is classically associated with which triad of risk factors?
- Hypertension, hyperglycemia, and dyslipidemia
- Virchow's triad: stasis, endothelial injury, hypercoagulability (Correct answer)
- Obesity, immobility, and female sex only
- Anemia, thrombocytopenia, and coagulopathy
Correct answer: Virchow's triad: stasis, endothelial injury, hypercoagulability
Virchow's triad — venous stasis, endothelial injury, and hypercoagulable state — describes the three main factors predisposing to DVT formation.
Question 5: A patient with Cushing's syndrome will most likely display which metabolic abnormality?
- Hypoglycemia due to excess insulin secretion
- Hyperglycemia due to cortisol-induced gluconeogenesis and insulin resistance (Correct answer)
- Hypokalemia with metabolic acidosis
- Hyponatremia with low serum osmolality
Correct answer: Hyperglycemia due to cortisol-induced gluconeogenesis and insulin resistance
Excess cortisol promotes hepatic gluconeogenesis and peripheral insulin resistance, commonly causing hyperglycemia and secondary diabetes mellitus.
Question 6: The hallmark laboratory finding in hemolytic anemia compared to blood loss anemia is which result?
- Low reticulocyte count in both conditions
- Elevated indirect bilirubin and elevated LDH in hemolysis (Correct answer)
- Low MCV in both conditions
- Elevated ferritin and transferrin saturation in hemolysis
Correct answer: Elevated indirect bilirubin and elevated LDH in hemolysis
Hemolysis releases intracellular LDH and hemoglobin (converted to indirect bilirubin), elevating both markers, which distinguishes hemolytic from blood loss anemia.
COMAT COMAT Pathophysiology and Disease Processes 2
Which pathophysiologic process underlies the conversion of stable atherosclerotic plaque to an acute coronary syndrome?