The Ultimate NBME CBSE High-Yield
Q-Bank: Core Clinical Vignettes with
Detailed Rationales for
Comprehensive Shelf Exam Mastery
1. A 45-year-old male with a history of alcohol abuse presents with
hematemesis and melena. On physical exam, he has spider angiomata
and palmar erythema. An upper endoscopy reveals bleeding
esophageal varices. Which of the following is the most likely
underlying mechanism for the development of varices?
A) Increased hepatic arterial flow
B) Decreased portal venous flow
C) Increased resistance to portal blood flow
D) Decreased splenic vein flow
E) Increased systemic venous return
Answer: C) Increased resistance to portal blood flow
Rationale: Cirrhosis leads to fibrosis and increased resistance to blood flow
through the liver, causing portal hypertension. This results in the formation
of portosystemic collaterals, including esophageal varices.
,2. A 30-year-old woman presents with fatigue, weight gain, and cold
intolerance. Laboratory studies reveal elevated TSH and low free T4. A
diagnosis of primary hypothyroidism is made. Which of the following
is the most likely cause?
A) Pituitary adenoma
B) Hashimoto thyroiditis
C) Graves disease
D) Subacute thyroiditis
E) Iodine excess
Answer: B) Hashimoto thyroiditis
Rationale: Hashimoto thyroiditis is the most common cause of primary
hypothyroidism in iodine-sufficient areas. It is an autoimmune disorder
characterized by lymphocytic infiltration and anti-thyroid peroxidase
antibodies.
3. A 55-year-old smoker presents with a 2-month history of hoarseness
and a sensation of a lump in the throat. Laryngoscopy reveals a lesion
on the left vocal cord. Biopsy shows squamous cell carcinoma in situ.
Which of the following is the most significant risk factor?
A) Alcohol consumption
B) Human papillomavirus infection
C) Tobacco smoking
D) Gastroesophageal reflux
E) Asbestos exposure
Answer: C) Tobacco smoking
Rationale: Tobacco smoking is the most significant risk factor for squamous
,cell carcinoma of the larynx. The combination of smoking and alcohol has a
synergistic effect.
4. A 60-year-old male with a history of hypertension and diabetes
presents with sudden onset of severe chest pain radiating to the back.
On exam, blood pressure is 100/60 mmHg in the right arm and 140/80
mmHg in the left arm. Which of the following is the most likely
diagnosis?
A) Myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
E) Esophageal rupture
Answer: C) Aortic dissection
Rationale: Aortic dissection often presents with sudden, severe chest pain
radiating to the back and may cause differential blood pressures between
arms. Risk factors include hypertension and connective tissue disorders.
5. A 28-year-old woman presents with palpitations, weight loss, and
heat intolerance. On exam, she has a fine tremor and exophthalmos.
Laboratory studies show low TSH and elevated free T4. Which of the
following is the most likely underlying mechanism?
A) TSH-secreting pituitary adenoma
B) Thyroid-stimulating immunoglobulins
C) Thyroid hormone resistance
, D) Toxic multinodular goiter
E) Subacute thyroiditis
Answer: B) Thyroid-stimulating immunoglobulins
Rationale: Graves disease is caused by autoantibodies that stimulate the
TSH receptor, leading to hyperthyroidism and exophthalmos.
6. A 50-year-old man with a history of chronic alcoholism presents
with confusion, ataxia, and nystagmus. He is diagnosed with Wernicke
encephalopathy. Which of the following is the most important
immediate treatment?
A) Vitamin B12
B) Thiamine
C) Folic acid
D) Niacin
E) Pyridoxine
Answer: B) Thiamine
Rationale: Wernicke encephalopathy is caused by thiamine (vitamin B1)
deficiency and is treated with prompt thiamine replacement.
7. A 75-year-old female presents with a hip fracture after a fall from
standing height. She has a history of rheumatoid arthritis treated with
corticosteroids. Which of the following best explains her increased risk
of fracture?
A) Osteomalacia
B) Osteoporosis
Q-Bank: Core Clinical Vignettes with
Detailed Rationales for
Comprehensive Shelf Exam Mastery
1. A 45-year-old male with a history of alcohol abuse presents with
hematemesis and melena. On physical exam, he has spider angiomata
and palmar erythema. An upper endoscopy reveals bleeding
esophageal varices. Which of the following is the most likely
underlying mechanism for the development of varices?
A) Increased hepatic arterial flow
B) Decreased portal venous flow
C) Increased resistance to portal blood flow
D) Decreased splenic vein flow
E) Increased systemic venous return
Answer: C) Increased resistance to portal blood flow
Rationale: Cirrhosis leads to fibrosis and increased resistance to blood flow
through the liver, causing portal hypertension. This results in the formation
of portosystemic collaterals, including esophageal varices.
,2. A 30-year-old woman presents with fatigue, weight gain, and cold
intolerance. Laboratory studies reveal elevated TSH and low free T4. A
diagnosis of primary hypothyroidism is made. Which of the following
is the most likely cause?
A) Pituitary adenoma
B) Hashimoto thyroiditis
C) Graves disease
D) Subacute thyroiditis
E) Iodine excess
Answer: B) Hashimoto thyroiditis
Rationale: Hashimoto thyroiditis is the most common cause of primary
hypothyroidism in iodine-sufficient areas. It is an autoimmune disorder
characterized by lymphocytic infiltration and anti-thyroid peroxidase
antibodies.
3. A 55-year-old smoker presents with a 2-month history of hoarseness
and a sensation of a lump in the throat. Laryngoscopy reveals a lesion
on the left vocal cord. Biopsy shows squamous cell carcinoma in situ.
Which of the following is the most significant risk factor?
A) Alcohol consumption
B) Human papillomavirus infection
C) Tobacco smoking
D) Gastroesophageal reflux
E) Asbestos exposure
Answer: C) Tobacco smoking
Rationale: Tobacco smoking is the most significant risk factor for squamous
,cell carcinoma of the larynx. The combination of smoking and alcohol has a
synergistic effect.
4. A 60-year-old male with a history of hypertension and diabetes
presents with sudden onset of severe chest pain radiating to the back.
On exam, blood pressure is 100/60 mmHg in the right arm and 140/80
mmHg in the left arm. Which of the following is the most likely
diagnosis?
A) Myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
E) Esophageal rupture
Answer: C) Aortic dissection
Rationale: Aortic dissection often presents with sudden, severe chest pain
radiating to the back and may cause differential blood pressures between
arms. Risk factors include hypertension and connective tissue disorders.
5. A 28-year-old woman presents with palpitations, weight loss, and
heat intolerance. On exam, she has a fine tremor and exophthalmos.
Laboratory studies show low TSH and elevated free T4. Which of the
following is the most likely underlying mechanism?
A) TSH-secreting pituitary adenoma
B) Thyroid-stimulating immunoglobulins
C) Thyroid hormone resistance
, D) Toxic multinodular goiter
E) Subacute thyroiditis
Answer: B) Thyroid-stimulating immunoglobulins
Rationale: Graves disease is caused by autoantibodies that stimulate the
TSH receptor, leading to hyperthyroidism and exophthalmos.
6. A 50-year-old man with a history of chronic alcoholism presents
with confusion, ataxia, and nystagmus. He is diagnosed with Wernicke
encephalopathy. Which of the following is the most important
immediate treatment?
A) Vitamin B12
B) Thiamine
C) Folic acid
D) Niacin
E) Pyridoxine
Answer: B) Thiamine
Rationale: Wernicke encephalopathy is caused by thiamine (vitamin B1)
deficiency and is treated with prompt thiamine replacement.
7. A 75-year-old female presents with a hip fracture after a fall from
standing height. She has a history of rheumatoid arthritis treated with
corticosteroids. Which of the following best explains her increased risk
of fracture?
A) Osteomalacia
B) Osteoporosis
