Table 1.

Causes of Secondary Sclerosing Cholangitis.^*

Cause	Proposed Pathogenesis
Abdominal trauma	Damage and subsequent strictures of the biliary tree
AIDS-related cholangiopathy	Biliary strictures associated with infection, most commonly due to Cryptosporidium parvum
Amyloidosis	Systemic disease involving the biliary tree
Cholangiocarcinoma	New development of cancer that mimics clinical presentation of primary sclerosing cholangitis
Choledocholithiasis	Strictures due to a stone or stones within the biliary tree
Eosinophilic cholangiopathy	Systemic disease involving the biliary tree
Graft-versus-host disease	Systemic disease involving the biliary tree
Hepatic inflammatory pseudotumor	Inflammatory condition that mimics cholangiographic features of primary sclerosing cholangitis
Histiocytosis X	Systemic disease involving the biliary tree
Iatrogenic biliary strictures	Strictures due to surgery or ERCP
IgG4-associated cholangitis	Systemic disorder that is characterized by high serum IgG4 levels and IgG4-positive lymphoplasmacytic infiltration of affected organs (the pancreas and bile ducts) and that causes biliary strictures
Intraarterial chemotherapy	Biliary strictures due to infusion offluorouracil chemotherapy through the hepatic artery
Ischemic cholangiopathy	Inadequate arterial supply of the biliary tree
Mast-cell cholangiopathy	Systemic disease involving the biliary tree
Portal hypertensive biliopathy	Extrahepatic portal venous obstruction causing compression and stricturing of the biliary tree
Recurrent pyogenic cholangitis	Progressive and diffuse biliary stricturing, ectasias, and local stone formation; common in East Asia
Sarcoidosis	Systemic disease involving the biliary tree

^*AIDS denotes acquired immunodeficiency syndrome, and ERCP endoscopic retrograde cholangiopancreatography.