Examination of the United States COMLEX-

Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX- USA) Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• A 45-year-old man presents with acute epigastric pain radiating to the

back after alcohol use. Serum amylase and lipase are elevated. What is the most likely diagnosis?

• Cholecystitis
• Acute pancreatitis
• Peptic ulcer disease
• Gastritis

Rationale: Elevated amylase and lipase with epigastric pain radiating to

the back indicate acute pancreatitis, commonly from alcohol use or gallstones._

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• A 23-year-old woman presents with dysuria and increased urinary

frequency. Urinalysis reveals leukocyte esterase and nitrites. The causative

organism is most likely:

• Staphylococcus saprophyticus
• Escherichia coli
• Proteus mirabilis
• Enterococcus faecalis

Rationale: E. coli is the most common cause of urinary tract infection in

young women._

• A 65-year-old man has resting tremor, rigidity, and bradykinesia. The

neurotransmitter imbalance responsible is:

• Increased dopamine and decreased acetylcholine
• Increased serotonin and dopamine
• Decreased dopamine and increased acetylcholine
• Decreased serotonin and norepinephrine

Rationale: Parkinson’s disease involves loss of dopaminergic neurons in

the substantia nigra leading to dopamine deficiency and relative acetylcholine excess._

• A newborn presents with continuous “machinery-like” murmur at the

left infraclavicular area. What congenital condition does this describe?

• Atrial septal defect 2 / 4

• Patent ductus arteriosus
• Ventricular septal defect
• Coarctation of the aorta

Rationale: A continuous murmur at the left infraclavicular region is classic

for patent ductus arteriosus due to persistent connection between the aorta and pulmonary artery._

• A patient with chronic obstructive pulmonary disease (COPD) has

chronic CO₂ retention. Which compensation occurs?

• Respiratory alkalosis
• Metabolic compensation with increased HCO₃⁻
• Respiratory acidosis without compensation
• Decreased renal HCO₃⁻ reabsorption

Rationale: The kidneys retain bicarbonate to compensate for chronic CO₂

retention in COPD._

• A 6-year-old develops a sore throat followed by a sandpaper-like rash

and strawberry tongue. The causative organism produces:

• Erythrogenic exotoxin
• Endotoxin
• Exfoliative toxin
• Tetanospasmin 3 / 4

Rationale: Scarlet fever from Streptococcus pyogenes is caused by

erythrogenic exotoxin, a superantigen._

• A 30-year-old woman with hyperthyroidism presents with

exophthalmos and pretibial myxedema. What is the underlying mechanism?

• TSH-secreting pituitary adenoma
• Autoantibody stimulation of TSH receptors
• Thyroid carcinoma
• Iodine deficiency

Rationale: Graves disease is an autoimmune condition where IgG

antibodies stimulate TSH receptors leading to thyroid hormone overproduction._

• A 25-year-old man presents with urethritis after unprotected sex. Gram

stain shows gram-negative diplococci. Which is the best treatment?

• Azithromycin alone
• Doxycycline alone
• Ceftriaxone plus doxycycline
• Ciprofloxacin

Rationale: Gonorrhea (Neisseria gonorrhoeae) requires ceftriaxone plus

doxycycline to cover possible Chlamydia coinfection._

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