2024 USMLE Practice Paper 2

1. Which of the following medications is associated with hepatotoxicity and requires monitoring of liver function tests during treatment?

A. Fragile X syndrome
B. Alport syndrome
C. Hypophosphatemic rickets
D. Leber hereditary optic neuropathy
E. Autosomal dominant optic atrophy

Correct Answer: A

Notes:

Bosentan, an endothelin receptor antagonist, is known to be hepatotoxic and requires monitoring of liver function tests (LFTs). Sildenafil, epoprostenol, iloprost, and nitroglycerin do not have the same requirement for LFT monitoring due to hepatotoxic effects.

2. A 48-year-old female presents with epigastric pain that radiates to the back. A CT scan reveals an enlarged pancreas with signs of inflammation. Which artery is the primary blood supply for the majority of the pancreas?

A. Superior mesenteric artery
B. Inferior mesenteric artery
C. Common hepatic artery
D. Celiac artery
E. Right gastric artery

Correct Answer: D

Notes:

The pancreas receives its primary blood supply from the celiac artery through its branches, including the splenic artery, which supplies the body and tail, and the pancreaticoduodenal arteries (anterior and posterior superior pancreaticoduodenal), which are branches of the celiac artery, supplying the head. Therefore, the celiac artery is the main source of blood supply to the pancreas. The superior mesenteric artery does contribute to the head of the pancreas through the inferior pancreaticoduodenal arteries, but it is not the primary supply.

3. A 13-year-old boy is brought to the clinic because he has no signs of puberty. On examination, he has no pubic hair and testicular volume is consistent with a pre-pubertal stage. What condition could be responsible for this presentation?

A. Idiopathic precocious puberty
B. GnRH-independent puberty
C. Klinefelter syndrome
D. Constitutional delay of growth and puberty
E. Ovarian tumor

Correct Answer: D

Notes:

Constitutional delay of growth and puberty (also known as ‘late blooming’) is a common cause of delayed puberty, particularly in boys. This condition involves a delayed but otherwise normal adolescent development process. Klinefelter syndrome is another cause of delayed puberty but typically associated with other features like small testes and tall stature. Idiopathic precocious puberty and GnRH-independent puberty would present with early signs of puberty, which contradicts the patient’s presentation. An ovarian tumor is not relevant in a male patient.

4. A 30-year-old male uses cannabis heavily and has been showing disorganized behavior, hallucinations, and flat affect for the past year. Brain imaging shows ventriculomegaly. What neurotransmitter alteration is most commonly associated with his condition?

A. Increased norepinephrine
B. Decreased serotonin
C. Altered dopamine activity
D. Decreased GABA activity
E. Increased acetylcholine

Correct Answer: C

Notes:

Schizophrenia is associated with altered dopaminergic activity, along with changes in serotonergic activity and dendritic branching. Ventriculomegaly is also a common brain imaging finding in schizophrenia. The patient’s chronic symptoms and imaging findings align with this diagnosis. Increased norepinephrine, decreased serotonin, decreased GABA activity, and increased acetylcholine are not primarily linked to schizophrenia.

5. A 32-year-old male is prescribed an NSAID for chronic back pain. After two weeks, he presents with reduced urine output and elevated serum creatinine levels. Which of the following describes the mechanism by which NSAIDs could lead to these changes in renal function?

A. Constriction of the afferent arteriole, reducing RPF and GFR
B. Constriction of the efferent arteriole, increasing GFR
C. Dilation of the efferent arteriole, increasing RPF
D. Inhibition of the renin-angiotensin system, reducing GFR
E. Dilation of the afferent arteriole, increasing GFR

Correct Answer: A

Notes:

NSAIDs block the production of prostaglandins, which normally dilate the afferent arteriole. This results in constriction of the afferent arteriole leading to decreased renal plasma flow (RPF) and glomerular filtration rate (GFR).

6. A 45-year-old woman with chronic pain is enrolled in a clinical therapeutic trial comparing the efficacy of a new pain reliever to a placebo. The study protocol uses a randomized, controlled, double-blind design. Which of the following best describes this type of study?

A. Subjects are assigned to the treatment or control group by the researchers analyzing the data.
B. Subjects and researchers analyzing the data are blinded to the assignments, but the researchers administering the treatments are not.
C. Subjects and all researchers, including those analyzing the data, do not know the group assignments.
D. Subjects serve as their own controls, and the order of treatments is randomized.
E. Subjects are analyzed according to the treatment they actually received, regardless of the original assignment.

Correct Answer: C

Notes:

In a double-blind study, neither the subjects nor the researchers involved in administering or measuring outcomes know which group the subjects are in, reducing bias. Triple-blind refers to blinding of even data analysts, but ‘C’ fits the standard double-blind description.

7. A 28-year-old man comes to the emergency department after experiencing a serious car accident. Over the next month, he has persistent nightmares, flashbacks, and avoids driving or anything related to the accident. He feels increasingly agitated and has difficulty sleeping. Which of the following is the most appropriate initial treatment?

A. Benzodiazepines
B. Cognitive-behavioral therapy (CBT)
C. Selective serotonin reuptake inhibitors (SSRIs)
D. Antipsychotic medication
E. Prazosin

Correct Answer: B

Notes:

The patient meets the criteria for acute stress disorder, which lasts between 3 days to 1 month following a traumatic event. The first-line treatment for acute stress disorder is cognitive-behavioral therapy (CBT). Pharmacotherapy, including SSRIs (C) and Prazosin (E), is typically reserved for post-traumatic stress disorder, where symptoms persist for more than 1 month. Benzodiazepines (A) and antipsychotic medication (D) are not first-line treatments for this condition.

8. A 29-year-old woman with hyperthyroidism is brought to the emergency department with high fever, agitation, and confusion. Examination reveals tachycardia and a mild tremor. Her family mentions she had a recent upper respiratory infection. Which of the following treatments should be initiated immediately?

A. Benzodiazepines
B. Cognitive-behavioral therapy (CBT)
C. Selective serotonin reuptake inhibitors (SSRIs)
D. Antipsychotic medication
E. Prazosin

Correct Answer: B

Notes:

The patient meets the criteria for acute stress disorder, which lasts between 3 days to 1 month following a traumatic event. The first-line treatment for acute stress disorder is cognitive-behavioral therapy (CBT). Pharmacotherapy, including SSRIs (C) and Prazosin (E), is typically reserved for post-traumatic stress disorder, where symptoms persist for more than 1 month. Benzodiazepines (A) and antipsychotic medication (D) are not first-line treatments for this condition.

9. A 50-year-old male presents to the emergency department after a suspected overdose. He consumed a substance that causes metabolic acidosis with an elevated anion gap. Physical examination reveals hyperventilation. Which of the following treatments should be administered first to this patient?

A. Fomepizole
B. N-acetylcysteine
C. Methylene blue
D. Vitamin K
E. Atropine

Correct Answer: A

Notes:

The patient’s presentation with metabolic acidosis and hyperventilation suggests methanol or ethylene glycol (antifreeze) poisoning. Fomepizole is the treatment of choice as it prevents the metabolism of methanol and ethylene glycol to their toxic metabolites. N-acetylcysteine is used for acetaminophen toxicity, methylene blue for methemoglobinemia, vitamin K for warfarin toxicity, and atropine for organophosphate poisoning.

10. A 30-year-old man with a longstanding history of cocaine abuse presents with chest pain and nosebleed. Physical examination reveals mydriasis and diaphoresis. Which of the following complications is most likely responsible for his symptoms?

A. Pulmonary embolism
B. Perforated nasal septum
C. Pneumothorax
D. Acute myocardial infarction
E. Esophageal rupture

Correct Answer: B

Notes:

Chronic use of cocaine may lead to a perforated nasal septum due to vasoconstriction and resulting ischemic necrosis. This explains the patient’s nosebleed. Although acute myocardial infarction is a serious complication of cocaine use (which might account for chest pain), the nosebleed paired with the nasal examination suggests perforated nasal septum.

Leave A Comment?