ACSM-EP Pathophysiology 2 — Questions and Answers
Question 1: Which pathophysiological mechanism primarily underlies type 2 diabetes mellitus?
- Autoimmune destruction of beta cells
- Insulin resistance combined with relative insulin deficiency (Correct answer)
- Complete absence of insulin secretion
- Excess glucagon secretion without insulin deficiency
Correct answer: Insulin resistance combined with relative insulin deficiency
Type 2 diabetes is characterized by peripheral insulin resistance combined with progressive beta-cell dysfunction leading to relative insulin deficiency.
Question 2: A patient with hypertrophic cardiomyopathy (HCM) is most at risk for sudden cardiac death during exercise due to which mechanism?
- Aortic valve rupture under increased cardiac output
- Left ventricular outflow tract obstruction and ventricular arrhythmias (Correct answer)
- Coronary artery spasm triggered by sympathetic activation
- Diastolic dysfunction causing pulmonary edema
Correct answer: Left ventricular outflow tract obstruction and ventricular arrhythmias
HCM can cause dynamic left ventricular outflow tract obstruction and fatal ventricular arrhythmias during high-intensity exercise.
Question 3: In chronic obstructive pulmonary disease (COPD), which pathological process is responsible for air trapping and hyperinflation?
- Bronchial wall thickening reducing airway diameter
- Loss of elastic recoil in alveolar walls due to emphysema (Correct answer)
- Increased mucus production blocking terminal bronchioles
- Pulmonary fibrosis reducing lung compliance
Correct answer: Loss of elastic recoil in alveolar walls due to emphysema
Destruction of alveolar walls in emphysema eliminates elastic recoil, causing airways to collapse during expiration and trap air.
Question 4: Which finding is most consistent with left ventricular heart failure during exercise?
- Decreased systemic vascular resistance
- Elevated pulmonary capillary wedge pressure (Correct answer)
- Reduced right atrial pressure
- Increased cardiac output above predicted maximum
Correct answer: Elevated pulmonary capillary wedge pressure
Left heart failure causes blood to back up into the pulmonary circulation, elevating pulmonary capillary wedge pressure.
Question 5: Peripheral artery disease (PAD) causes exercise-induced leg pain (claudication) primarily through which pathophysiological mechanism?
- Lactic acid accumulation from over-training
- Ischemia distal to atherosclerotic arterial stenosis (Correct answer)
- Venous insufficiency causing compartment syndrome
- Neuropathic pain from lumbar nerve compression
Correct answer: Ischemia distal to atherosclerotic arterial stenosis
Atherosclerotic plaques narrow arterial lumen, limiting blood flow to exercising muscles and causing ischemic pain that resolves with rest.
Question 6: What is the primary cardiac adaptation that distinguishes pathological hypertrophy from exercise-induced physiological hypertrophy?
- Increased stroke volume in pathological hypertrophy
- Fibrosis and impaired diastolic function in pathological hypertrophy (Correct answer)
- Greater wall thickness in physiological hypertrophy
- Normal ejection fraction only in pathological hypertrophy
Correct answer: Fibrosis and impaired diastolic function in pathological hypertrophy
Pathological hypertrophy features fibrosis, cardiomyocyte death, and diastolic dysfunction, whereas physiological hypertrophy maintains or improves cardiac function.
Question 7: In metabolic syndrome, which combination of risk factors is required for diagnosis according to ATP III criteria?
- Three or more of: abdominal obesity, elevated triglycerides, low HDL, hypertension, elevated fasting glucose (Correct answer)
- Elevated LDL plus two of: hypertension, obesity, diabetes
- Any two of: insulin resistance, dyslipidemia, hypertension
- BMI >30 plus elevated fasting insulin
Correct answer: Three or more of: abdominal obesity, elevated triglycerides, low HDL, hypertension, elevated fasting glucose
ATP III requires three or more of five criteria: waist circumference >102 cm (men)/88 cm (women), triglycerides ≥150 mg/dL, HDL <40/50 mg/dL, BP ≥130/85 mmHg, fasting glucose ≥110 mg/dL.
ACSM-EP Pathophysiology 2
Which pathophysiological mechanism primarily underlies type 2 diabetes mellitus?