APEA Advanced Pathophysiology — Questions and Answers
Question 1: A patient with type 1 diabetes in diabetic ketoacidosis has deep, rapid respirations (Kussmaul breathing). What is the physiologic purpose of this breathing pattern?
- To compensate for metabolic acidosis by blowing off CO2 (Correct answer)
- To compensate for respiratory alkalosis by retaining CO2
- To correct hypoxemia caused by pulmonary edema
- To reduce the work of breathing from ketone accumulation
Correct answer: To compensate for metabolic acidosis by blowing off CO2
Ketoacids lower serum pH and bicarbonate. Hyperventilation lowers PaCO2, which raises pH and partially compensates for the metabolic acidosis.
Question 2: In heart failure with reduced ejection fraction, which compensatory mechanism contributes most to long-term adverse ventricular remodeling?
- Chronic activation of the renin-angiotensin-aldosterone system and sympathetic nervous system (Correct answer)
- Decreased release of antidiuretic hormone
- Increased release of atrial natriuretic peptide
- Decreased venous return from vasodilation
Correct answer: Chronic activation of the renin-angiotensin-aldosterone system and sympathetic nervous system
Neurohormonal activation helps short-term by maintaining perfusion pressure. Over time, angiotensin II, aldosterone, and catecholamines cause fibrosis, hypertrophy, and increased afterload, which is why ACE inhibitors, ARBs, ARNIs, beta-blockers, and MRAs are core therapy.
Question 3: Which laboratory pattern is the hallmark of nephrotic syndrome?
- Proteinuria above 3.5 g/day with hypoalbuminemia (Correct answer)
- Hematuria with red blood cell casts and hypertension
- Hyperkalemia with low urine output
- Pyuria with white blood cell casts and fever
Correct answer: Proteinuria above 3.5 g/day with hypoalbuminemia
Damage to the glomerular filtration barrier causes massive protein loss. This produces hypoalbuminemia, edema, hyperlipidemia, and lipiduria. Hematuria with RBC casts points to nephritic syndrome.
Question 4: A positive tuberculin skin test and allergic contact dermatitis from nickel are examples of which type of hypersensitivity reaction?
- Type I (IgE-mediated)
- Type II (cytotoxic)
- Type III (immune complex)
- Type IV (delayed, T-cell mediated) (Correct answer)
Correct answer: Type IV (delayed, T-cell mediated)
Type IV reactions are mediated by sensitized T cells and appear 48 to 72 hours after exposure. They do not involve antibodies.
Question 5: Which combination of factors makes up Virchow's triad for venous thrombosis?
- Stasis, endothelial injury, and hypercoagulability (Correct answer)
- Hypertension, hyperlipidemia, and smoking
- Fever, tachycardia, and hypoxia
- Anemia, thrombocytopenia, and vasculitis
Correct answer: Stasis, endothelial injury, and hypercoagulability
Venous thrombus formation results from venous stasis, vessel wall (endothelial) injury, and a hypercoagulable state. Examples are immobility, surgery or trauma, and malignancy or estrogen use.
Question 6: Excess cortisol in Cushing syndrome most directly causes hyperglycemia through which mechanism?
- Increased hepatic gluconeogenesis and peripheral insulin resistance (Correct answer)
- Destruction of pancreatic beta cells
- Decreased glucagon secretion
- Increased renal glucose reabsorption
Correct answer: Increased hepatic gluconeogenesis and peripheral insulin resistance
Glucocorticoids stimulate hepatic gluconeogenesis, promote protein breakdown to supply substrates, and reduce peripheral glucose uptake. The result is hyperglycemia and sometimes steroid-induced diabetes.
