NBME CBSE Real Exam Questions And Correct Answers With Rationales.

NBME CBSE Real Exam Questions And Correct
Answers With Rationales




NBME CBSE Practice Questions (Set 1)

Question 1

A 65-year-old man presents with chest pain radiating to his left arm. ECG shows ST elevation in leads
II, III, and aVF. Which coronary artery is most likely occluded?

• A. Left anterior descending

• B. Left circumflex

• C. Right coronary artery

• D. Posterior descending

Rationale: ST elevation in II, III, and aVF indicates an inferior wall MI, usually due to right coronary
artery occlusion. LAD affects anterior wall; circumflex affects lateral wall; PDA supplies posterior wall.

Question 2

A patient with chronic alcohol use presents with confusion, ataxia, and ophthalmoplegia. Which
vitamin deficiency is most likely?

• A. Vitamin B1 (Thiamine)

• B. Vitamin B6 (Pyridoxine)

• C. Vitamin B12 (Cobalamin)

• D. Vitamin B3 (Niacin)

Rationale: Classic triad of Wernicke’s encephalopathy is due to thiamine deficiency. Alcohol impairs
absorption and storage. Other B vitamins cause different neurologic or hematologic issues.

Question 3

A newborn has persistent vomiting after feeding and a distended abdomen. Imaging shows a "double
bubble" sign. What is the most likely diagnosis?

• A. Duodenal atresia

• B. Pyloric stenosis

• C. Hirschsprung disease

, • D. Malrotation with volvulus

Rationale: Double bubble sign = stomach + proximal duodenum dilation → duodenal atresia, often
associated with Down syndrome. Pyloric stenosis shows projectile vomiting but no double bubble.

Question 4

Which neurotransmitter is decreased in both Parkinson’s disease and depression?

• A. Dopamine

• B. Serotonin

• C. GABA

• D. Acetylcholine

Rationale: Parkinson’s involves loss of dopaminergic neurons in substantia nigra. Dopamine
deficiency also contributes to depression. Serotonin is decreased in depression but not Parkinson’s.

Question 5

A patient develops hemolytic anemia after taking sulfa drugs. Which enzyme deficiency is most
likely?

• A. Glucose-6-phosphate dehydrogenase (G6PD)

• B. Pyruvate kinase

• C. Hexokinase

• D. Lactate dehydrogenase

Rationale: G6PD deficiency → impaired NADPH production → oxidative stress → hemolysis after
sulfa drugs, fava beans, or infections.

Question 6

A 40-year-old woman presents with heat intolerance, weight loss, and palpitations. Labs show
decreased TSH and elevated free T4. What is the most likely diagnosis?

• A. Hashimoto thyroiditis

• B. Subacute thyroiditis

• C. Graves disease

• D. Toxic multinodular goiter

Rationale: Graves disease = autoimmune stimulation of TSH receptor → ↑T4, ↓TSH. Hashimoto =
hypothyroidism. Subacute thyroiditis = painful thyroid. Toxic multinodular goiter = multiple nodules.

Question 7

Which of the following is a side effect of long-term corticosteroid use?

• A. Hypoglycemia

• B. Osteoporosis