A 45-year-old man presents with severe epigastric pain radiating to the back, vomiting, and serum lipase three times the upper limit. The initiating event in acute pancreatitis is best explained by:

• A Excess secretion of inactive proenzymes into the duodenum
• B Premature activation of trypsinogen to trypsin within pancreatic acinar cells ✓
• C Auto-digestion caused by premature secretion of enterokinase from the duodenum
• D Failure of cholecystokinin release leading to ductal obstruction

Explanation

Pancreatic proteases are synthesized as inactive zymogens precisely to protect the gland. In acute pancreatitis, injury, duct obstruction, or alcohol-related stress triggers premature intracellular activation of trypsinogen to trypsin, which then autocatalytically activates all other zymogens, producing enzymatic autodigestion of the parenchyma. Secretion of inactive proenzymes into the duodenum is the normal safe pathway. Enterokinase acts physiologically inside the intestinal lumen, not within acinar cells, so option C misplaces the event.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.