USMLE PRACTICE QUESTION #50
TOPIC: GI Pathophysiology.
Today’s question will test your understanding of the underlying pathology associated with rheumatoid arthritis.
I’m Paul Ciurysek, MD, and this is The USMLE Times: An independent, subscriber-supported newsletter designed to help you survive medical school, pass your USMLE exams, and match into your dream residency program.
A 45-year-old male presents to the emergency department with severe epigastric pain radiating to his back, nausea, and vomiting for the past 12 hours. He reports a history of heavy alcohol consumption and has been binge-drinking over the past week. His vital signs include a temperature of 100.4°F (38°C), heart rate of 105/minute, respiratory rate of 22/minute, and blood pressure of 125/80 mmHg. Physical examination reveals a distended, tender abdomen with decreased bowel sounds. Laboratory studies show elevated serum amylase and lipase levels. An abdominal CT scan demonstrates a diffusely enlarged pancreas with peripancreatic fat stranding. Which of the following processes best explains the development of this patient's condition?
A. Impaired secretion of pancreatic enzymes
B. Increased production of trypsinogen
C. Premature activation of trypsinogen to trypsin
D. Autoimmune destruction of pancreatic acinar cells
E. Direct toxic effect of alcohol on pancreatic tissue
F. Obstruction of the pancreatic duct by gallstones
G. Reduced clearance of secreted pancreatic enzymes
Detailed Breakdown of Answers + Correct Answer Below ⏬
ANSWER + QUESTION BREAKDOWN
The mental model for this question comes from our detailed test-taking skills masterclass (A solid strategy can instantly boost USMLE question scores by 15-20%. If that sounds good, check out our test-taking skills masterclass HERE). Here’s how to think through this question:
Step 1. Determine what the question is asking: Identify the process that best explains the patient’s presentation.
Step 2: Is this a first-, second-, or third-order question?
Answer: 2nd order (1st. Diagnose, 2nd. ID the underlying process).
Step 3. Read the vignette and make a diagnosis.
Step 4. With a diagnosis in hand, ask yourself what’s underlying this problem.
Step 5. Look at the answer choices and select the option most closely resembling your thoughts from “Step 4” above.
GENERAL ANALYSIS
This question describes a 45-year-old male with symptoms and laboratory findings indicative of acute pancreatitis. The key clinical features include severe epigastric pain radiating to the back, nausea, vomiting, a history of heavy alcohol consumption, elevated serum amylase and lipase levels, and CT findings of an enlarged pancreas with peripancreatic fat stranding. The task is to identify the process that best explains this patient's development of acute pancreatitis.
ANSWER CHOICES:
ANSWER CHOICE A: Impaired secretion of pancreatic enzymes
Impaired secretion of pancreatic enzymes would lead to digestive issues but is not the primary cause of acute pancreatitis.
ANSWER CHOICE B: Increased production of trypsinogen
Increased production of trypsinogen could theoretically lead to more enzyme activity, but it is not the direct cause of acute pancreatitis.
ANSWER CHOICE C: Premature activation of trypsinogen to trypsin
Acute pancreatitis is often caused by the premature activation of trypsinogen to trypsin within the pancreas, leading to autodigestion and inflammation.
ANSWER CHOICE D: Autoimmune destruction of pancreatic acinar cells
Autoimmune destruction would be more characteristic of chronic pancreatitis or autoimmune pancreatitis.
ANSWER CHOICE E: Direct toxic effect of alcohol on pancreatic tissue
Alcohol can have a direct toxic effect on the pancreas, contributing to acute pancreatitis.
ANSWER CHOICE F: Obstruction of the pancreatic duct by gallstones
Gallstones can cause acute pancreatitis by obstructing the pancreatic duct.
ANSWER CHOICE G: Reduced clearance of secreted pancreatic enzymes
Reduced clearance could lead to enzyme buildup but is not the primary cause of acute pancreatitis.
FINAL VERDICT…
Acute pancreatitis is characterized by the premature activation of digestive enzymes within the pancreas. Normally, trypsinogen is secreted into the duodenum, where it is converted to trypsin. In acute pancreatitis, trypsinogen is prematurely activated to trypsin within the pancreas, leading to autodigestion of pancreatic tissue and inflammation. This process results in this patient's clinical symptoms and laboratory findings. Alcohol consumption is a well-known risk factor for acute pancreatitis, as it can lead to increased permeability of pancreatic duct cells and enzyme activation. While alcohol can have direct toxic effects, the immediate cause of acute pancreatitis is the premature activation of trypsinogen.
CORRECT ANSWER: C) Premature activation of trypsinogen to trypsin
That’s all for today 👋
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