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PH-GI08

Acute pancreatitis

How the pancreas normally keeps its powerful digestive enzymes inactive until they reach the gut, why gallstones and alcohol trigger their activation inside the gland, and how the resulting self-digestion spreads into a body-wide inflammatory illness.

By the end, you can

  • Describe the exocrine pancreas, its ducts and how enzymes are kept inactive until they reach the duodenum.
  • Explain how gallstones, alcohol and other causes lead to premature activation of trypsin.
  • Explain autodigestion, fat necrosis and haemorrhage within and around the pancreas.
  • Explain how local inflammation becomes a systemic inflammatory response with organ failure.
  • Relate the pain, raised enzymes, low calcium and other findings to the mechanism.
  • Recognise fat necrosis, haemorrhagic pancreatitis and the revised Atlanta classification, interpret the key numbers and tests, and explain how fluids, analgesia, feeding, ERCP, antibiotics and drainage act on the mechanism.

What it is

Acute pancreatitis is acute inflammation of the pancreas caused by activation of its digestive enzymes within the gland. It ranges from mild, with swelling (oedematous pancreatitis) that settles within days, to severe, with necrosis of the gland and failure of other organs. Gallstones and alcohol cause most cases.

2 types to tell apart
Mild (interstitial oedematous)
Inflammation and swelling without organ failure; most patients recover within a week.
Severe (often necrotising)
Persistent organ failure, often with necrosis of the pancreas and surrounding fat; can be fatal.

US spelling: oedematous → edematous.

Normal function

Enzymes made safe until they reach the gut

Acinar cells of the make enzymes that digest protein, fat and starch. The protein-digesting enzymes are made as inactive precursors, chiefly trypsinogen, stored in granules with a trypsin inhibitor.

They travel down the , which joins the bile duct to open into the duodenum at the . There, an enzyme of the intestinal lining (enteropeptidase) converts trypsinogen to trypsin, which then activates the other enzymes, safely inside the gut.

Several safeguards protect the gland: inactive precursors, inhibitors, rapid flow of alkaline juice and the separation of enzymes from the lysosomes that could activate them.

Point to it on the model