COMSAE Phase 1 ASA 111i
Mastery Edition: 100 High-
Yield Board-Style Practice
Questions with Detailed
Rationales | Comprehensive
COMLEX-USA Level 1 Revision
Exam
1. A 24-year-old man presents with fatigue, dark urine, and jaundice two days
after taking trimethoprim-sulfamethoxazole for a urinary tract infection.
Laboratory studies reveal elevated indirect bilirubin, increased lactate
dehydrogenase, and decreased haptoglobin. A peripheral smear shows bite
cells. Which enzyme deficiency is the most likely cause of this patient's
condition?
A. Pyruvate kinase deficiency
B. Glucose-6-phosphate dehydrogenase deficiency
C. Hexokinase deficiency
D. Glucose-6-phosphatase deficiency
,E. Fructokinase deficiency
Rationale: G6PD deficiency results in impaired production of NADPH, making
erythrocytes susceptible to oxidative damage from drugs, infections, or fava
beans. Bite cells result from splenic removal of Heinz bodies.
2. A 68-year-old woman presents with progressive shortness of breath and
orthopnea. Echocardiography demonstrates reduced left ventricular
ejection fraction. Which compensatory mechanism initially helps maintain
cardiac output?
A. Decreased sympathetic activity
B. Increased parasympathetic activity
C. Activation of the Frank-Starling mechanism
D. Decreased renin release
E. Reduced preload
Rationale: Increased ventricular filling stretches myocardial fibers, enhancing
contractility via the Frank-Starling mechanism before chronic compensation
becomes maladaptive.
3. A 5-year-old child develops fever, sore throat, and a sandpaper-like rash.
Examination reveals strawberry tongue and circumoral pallor. Which
organism is responsible?
A. Staphylococcus aureus
B. Corynebacterium diphtheriae
C. Streptococcus pyogenes
D. Haemophilus influenzae
E. Neisseria meningitidis
, Rationale: Scarlet fever is caused by Group A Streptococcus producing
erythrogenic exotoxins.
4. A patient develops weakness in extending the wrist after sustaining a
midshaft fracture of the humerus. Which nerve has most likely been
injured?
A. Median nerve
B. Ulnar nerve
C. Musculocutaneous nerve
D. Axillary nerve
E. Radial nerve
Rationale: The radial nerve courses through the radial groove of the humerus and
is vulnerable in midshaft fractures, causing wrist drop.
5. A researcher administers a drug that competitively inhibits HMG-CoA
reductase. Which metabolic pathway is directly inhibited?
A. Glycolysis
B. β-Oxidation
C. Urea cycle
D. Cholesterol synthesis
E. Glycogenolysis
Rationale: Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in
cholesterol biosynthesis.
Mastery Edition: 100 High-
Yield Board-Style Practice
Questions with Detailed
Rationales | Comprehensive
COMLEX-USA Level 1 Revision
Exam
1. A 24-year-old man presents with fatigue, dark urine, and jaundice two days
after taking trimethoprim-sulfamethoxazole for a urinary tract infection.
Laboratory studies reveal elevated indirect bilirubin, increased lactate
dehydrogenase, and decreased haptoglobin. A peripheral smear shows bite
cells. Which enzyme deficiency is the most likely cause of this patient's
condition?
A. Pyruvate kinase deficiency
B. Glucose-6-phosphate dehydrogenase deficiency
C. Hexokinase deficiency
D. Glucose-6-phosphatase deficiency
,E. Fructokinase deficiency
Rationale: G6PD deficiency results in impaired production of NADPH, making
erythrocytes susceptible to oxidative damage from drugs, infections, or fava
beans. Bite cells result from splenic removal of Heinz bodies.
2. A 68-year-old woman presents with progressive shortness of breath and
orthopnea. Echocardiography demonstrates reduced left ventricular
ejection fraction. Which compensatory mechanism initially helps maintain
cardiac output?
A. Decreased sympathetic activity
B. Increased parasympathetic activity
C. Activation of the Frank-Starling mechanism
D. Decreased renin release
E. Reduced preload
Rationale: Increased ventricular filling stretches myocardial fibers, enhancing
contractility via the Frank-Starling mechanism before chronic compensation
becomes maladaptive.
3. A 5-year-old child develops fever, sore throat, and a sandpaper-like rash.
Examination reveals strawberry tongue and circumoral pallor. Which
organism is responsible?
A. Staphylococcus aureus
B. Corynebacterium diphtheriae
C. Streptococcus pyogenes
D. Haemophilus influenzae
E. Neisseria meningitidis
, Rationale: Scarlet fever is caused by Group A Streptococcus producing
erythrogenic exotoxins.
4. A patient develops weakness in extending the wrist after sustaining a
midshaft fracture of the humerus. Which nerve has most likely been
injured?
A. Median nerve
B. Ulnar nerve
C. Musculocutaneous nerve
D. Axillary nerve
E. Radial nerve
Rationale: The radial nerve courses through the radial groove of the humerus and
is vulnerable in midshaft fractures, causing wrist drop.
5. A researcher administers a drug that competitively inhibits HMG-CoA
reductase. Which metabolic pathway is directly inhibited?
A. Glycolysis
B. β-Oxidation
C. Urea cycle
D. Cholesterol synthesis
E. Glycogenolysis
Rationale: Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in
cholesterol biosynthesis.
