With ascending cholangitis, “cholang-” refers to the bile ducts and “-itis” refers to inflammation which is usually caused by a bacterial infection.
These bacteria are normally found in the intestines and work their way up the bile ducts from the duodenum of the small intestine, so that’s why it’s known as ascending cholangitis, also sometimes acute cholangitis because it can happen over a relatively short period of time.
Normally bacteria from the gut has a pretty tough time ascending up the bile ducts, and this is because bile flows down from the gallbladder, along with some pancreatic juice from the pancreas, into the duodenum, and this tends to flush out any bacteria trying to sneak their way up.
In ascending cholangitis this flow of bile is often blocked, and one common reason is choledocholithiasis, which refers to gallstones in the common bile duct.
In choledocholithiasis, gallstones form in the gallbladder and occasionally slip out, travel through the cystic bile duct, and then lodge into the common bile duct, obstructing the normal flow of bile.
These gallstones are typically made up of bile components, and risk factors for developing them include things like female sex, obesity, pregnancy, and age, sometimes remembered by the 4 F’s—female, fat, fertile, and forty. Other, less common causes include things that cause stricture, or narrowing of the bile ducts—like a nearby cancerous growth, which can compress the duct as the tumor slowly enlarges, or injury experienced during a laparoscopic procedure.
Once the flow of bile is blocked, bacteria can slowly make their way up the ducts and colonize the biliary system without the risk of being washed away.
Most commonly the bacterial species involved are a mixture of enteric organisms including common ones like E coli, Klebsiella species, and Enterococcus species.