Ascending Cholangitis
Bacteria multiply in bile trapped behind an obstructed common bile duct, and rising pressure in the duct drives them into the bloodstream.
Definition
Acute cholangitis is bacterial infection of the biliary tree arising behind an obstructed common bile duct, most often from a gallstone that has migrated into the duct. The diagnosis rests on systemic inflammation, cholestasis and imaging evidence of biliary obstruction, not on the classic triad alone.
First principles
Two things must be true: obstruction and infection
Neither alone produces cholangitis. A colonised duct that drains freely rarely makes a patient septic, and an obstructed duct that stays sterile produces painless jaundice. Put the two together and the pressure mechanism above takes over. A migrated gallstone is the commonest cause. Benign stricture, tumour, a blocked or migrated biliary stent and recent instrumentation account for the rest. This is also why antibiotics alone fail: they do nothing to the pressure.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.