What is the most common cause of cholangitis?

The most common cause of cholangitis is choledocholithiasis, which refers to the presence of gallstones in the common bile duct. While bacterial infection is a key component of cholangitis, it typically occurs secondary to the obstruction caused by gallstones. When a stone blocks the bile duct, it can lead to bile stasis, allowing for bacterial overgrowth and subsequent infection. This is termed ascending cholangitis, where the bacteria ascend from the duodenum into the biliary tree due to the blockage.

In summary, while a bacterial infection contributes significantly to the clinical picture of cholangitis, the underlying cause is usually choledocholithiasis, which necessitates addressing the obstructive process to resolve the infection effectively. Identifying and managing the source of the obstruction is crucial in treating cholangitis successfully.