Fat malabsorption (steatorrhea) in chronic pancreatitis is predominantly due to deficiency of which pancreatic enzyme, and what is the minimum residual enzyme output that typically prevents clinically significant steatorrhea?

• A Pancreatic amylase; >30% residual output prevents steatorrhea
• B Pancreatic lipase; >10% residual output is sufficient to prevent steatorrhea
• C Phospholipase A2; 1% residual output is sufficient for adequate fat emulsification
• D Pancreatic lipase (and co-lipase); steatorrhea appears when lipase output falls below approximately 5-10% of normal ✓

Explanation

Pancreatic exocrine secretion has enormous reserve capacity. Clinically significant fat malabsorption (steatorrhea >7g fat/day) develops only when lipase secretion falls below approximately 5-10% of normal output. This remarkable reserve means that steatorrhea is a late manifestation of chronic pancreatitis, indicating severe exocrine destruction. Lipase (along with co-lipase, which anchors lipase to bile salt-coated fat droplets and activates it) is the critical enzyme because no significant alternative for triglyceride hydrolysis exists in humans (unlike protein, where multiple proteases overlap). Protein malabsorption and steatorrhea thus develop at different thresholds of exocrine insufficiency.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.