Composite Index for Outcome Burden in Acute Cholangitis

Inclusion Criteria * Age 18 to 80 years * Hospital admission with definite diagnosis of acute cholangitis meeting TG18 diagnostic criteria * TG18 Grade I (Mild) Grade II (moderate) or Grade III (severe) at presentation/admission or prior to drainage. * Underwent biliary drainage attempt (ERCP/PTBD/EUS-BD) or were planned for drainage (including failures with rescue drainage). * First episode of index BD in case of patients undergoing multiple episodes of index BD as per operational definitions (Technical supplement 1) * Planned repeat BD in same admission shall be considered as continuation of the index BD and all the procedural details shall be documented and analysed. Exclusion Criteria * Pregnant women * Missing key outcome data (minimum required: mortality status + ICU admission status + Length of stay) * Non-biliary sepsis without evidence of biliary obstruction/infection on review. * A patients with past history of BD outside the study setting (As this is akin to second episode of Index BD) * Subsequent episodes of Index BD (other than the first index BD episode) among patients with more than one episode of Index BD.