ACSM-EP Pathophysiology 5 — Questions and Answers
Question 1: Which pathophysiological mechanism explains why fibromyalgia patients experience widespread pain hypersensitivity?
- Elevated systemic inflammatory markers damaging peripheral nerve endings
- Central sensitization with amplified pain signaling in the spinal cord and brain (Correct answer)
- Autoimmune attack on muscle spindles reducing pain threshold
- Mitochondrial dysfunction in type I muscle fibers causing chronic ischemic pain
Correct answer: Central sensitization with amplified pain signaling in the spinal cord and brain
Fibromyalgia involves central sensitization where the central nervous system amplifies nociceptive signals, causing widespread pain disproportionate to peripheral stimuli.
Question 2: In a patient with stroke resulting in hemiplegia, which secondary musculoskeletal pathology is most likely to develop without proper exercise intervention?
- Myositis ossificans in the paretic limb from spastic muscle contraction
- Disuse atrophy and spastic contracture in the affected limbs (Correct answer)
- Hypertrophy of antagonist muscles compensating for paretic agonists
- Heterotopic ossification in periarticular tissues from immobility
Correct answer: Disuse atrophy and spastic contracture in the affected limbs
Upper motor neuron lesions from stroke cause spasticity and paresis; without movement, muscles atrophy and spastic muscles shorten into contractures limiting joint range of motion.
Question 3: Which physiological abnormality is the primary driver of exercise intolerance in patients with systolic heart failure?
- Blunted peripheral vasodilation limiting muscle perfusion during exercise
- Severely reduced cardiac output reserve due to depressed left ventricular contractility (Correct answer)
- Excessive ventilatory response creating dyspnea before cardiovascular limits
- Skeletal muscle mitochondrial dysfunction limiting oxygen extraction
Correct answer: Severely reduced cardiac output reserve due to depressed left ventricular contractility
Depressed left ventricular systolic function limits the heart's ability to increase stroke volume and cardiac output during exercise, creating the primary ceiling on aerobic capacity.
Question 4: A 45-year-old woman with polycystic ovary syndrome (PCOS) presents for exercise programming. The EP should be aware that PCOS most commonly involves which pathophysiological process?
- Primary ovarian failure causing estrogen deficiency and bone loss
- Insulin resistance and hyperandrogenism affecting metabolic and reproductive function (Correct answer)
- Autoimmune thyroid destruction causing anovulatory cycles
- Hyperprolactinemia suppressing gonadotropin releasing hormone
Correct answer: Insulin resistance and hyperandrogenism affecting metabolic and reproductive function
PCOS is characterized by insulin resistance, compensatory hyperinsulinemia, and excess androgen production, predisposing women to metabolic syndrome and type 2 diabetes.
Question 5: Which pathological change in atherosclerosis is most responsible for acute myocardial infarction rather than stable angina?
- Progressive luminal narrowing exceeding 70% stenosis causing demand ischemia
- Fibrous cap rupture triggering complete thrombotic occlusion of the coronary artery (Correct answer)
- Calcification of the plaque core reducing vessel wall compliance
- Smooth muscle cell migration into the intima increasing plaque volume
Correct answer: Fibrous cap rupture triggering complete thrombotic occlusion of the coronary artery
Acute MI occurs when a vulnerable plaque's thin fibrous cap ruptures, exposing thrombogenic lipid core contents that trigger rapid platelet aggregation and complete vessel occlusion.
Question 6: Exercise capacity is most severely limited in which stage of chronic heart failure according to the NYHA classification?
- NYHA Class I — symptoms only with extreme exertion
- NYHA Class II — symptoms with moderate exertion
- NYHA Class III — symptoms with minimal exertion limiting ordinary activity
- NYHA Class IV — symptoms at rest or with any physical activity (Correct answer)
Correct answer: NYHA Class IV — symptoms at rest or with any physical activity
NYHA Class IV represents the most severe heart failure, where patients experience symptoms (dyspnea, fatigue) at rest or with minimal physical activity.
Question 7: In patients with multiple sclerosis (MS), exercise-induced fatigue and symptom worsening with heat is known as:
- Borg phenomenon causing central pain sensitization during hyperthermia
- Uhthoff's phenomenon from heat-related slowing of demyelinated nerve conduction (Correct answer)
- Lhermitte's sign triggered by spinal cord temperature elevation
- Heat syncope from dysautonomia impairing vasomotor thermoregulation
Correct answer: Uhthoff's phenomenon from heat-related slowing of demyelinated nerve conduction
Uhthoff's phenomenon occurs because increased core temperature further impairs already-compromised conduction through demyelinated axons, temporarily worsening neurological symptoms.
ACSM-EP Pathophysiology 5
Which pathophysiological mechanism explains why fibromyalgia patients experience widespread pain hypersensitivity?