Tuesday, April 2, 2024

Repeated USMLE Questions Step 1- 1001

 Q- A 45-year-old man presents to the emergency department with severe abdominal pain, nausea, and vomiting. He reports a history of heavy alcohol consumption for the past 20 years. Physical examination reveals jaundice and tenderness in the epigastric region. Laboratory studies show elevated serum levels of amylase and lipase. An abdominal ultrasound reveals gallstones. Which of the following mechanisms best explains the development of his pancreatic injury?

(A) Autoimmune destruction of pancreatic acinar cells (B) Obstruction of the pancreatic duct by gallstones (C) Ischemic injury due to decreased blood flow to the pancreas (D) Direct toxic effects of alcohol on pancreatic tissue (E) Excessive activation of pancreatic proteolytic enzymes

Answer

This patient's presentation is consistent with acute pancreatitis, a condition characterized by inflammation of the pancreas. The most common cause of acute pancreatitis in adults is gallstones, followed by alcohol consumption.

Chronic alcohol consumption can directly lead to pancreatic injury through several mechanisms, including:

  1. Direct toxic effects: Alcohol and its metabolites can directly damage pancreatic acinar cells, leading to inflammation and necrosis.

  2. Activation of pancreatic enzymes: Alcohol can stimulate the secretion of pancreatic enzymes such as amylase and lipase, which can lead to autodigestion of pancreatic tissue and inflammation.

  3. Impaired pancreatic blood flow: Alcohol can cause vasoconstriction of pancreatic blood vessels, leading to ischemia and subsequent tissue injury.

In this case, the patient's history of heavy alcohol consumption, along with laboratory findings consistent with acute pancreatitis and the presence of gallstones, suggests that the most likely mechanism for his pancreatic injury is the direct toxic effects of alcohol on pancreatic tissue.

Therefore, choice (D) is the correct answer.

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