Acute Cholecystitis
A gallstone impacts persistently at the cystic duct, so unlike transient biliary colic the gallbladder wall distends, becomes ischaemic and secondarily infected, producing continuous pain, fever and a positive Murphy's sign.
First principles
Why persistent impaction changes the disease entirely
In biliary colic a stone at the cystic duct or Hartmann's pouch disimpacts and the gallbladder empties. In acute cholecystitis it does not: the stone stays lodged, the gallbladder cannot drain, and bile builds up under pressure. The stagnant, concentrated bile is chemically irritant to the mucosa, and venous and lymphatic congestion from the distended wall causes ischaemia. This chemical inflammation is then typically compounded by secondary bacterial infection (commonly E. coli, Klebsiella, Enterococcus) ascending from the gut: the gallbladder wall becomes a truly inflamed, infected organ rather than just a mechanically obstructed one.
Educational content pending clinical review. Not medical advice.