Diagnosis
The diagnosis is by imaging of the bile duct, usually in the setting of endoscopic retrograde cholangiopancreatography (ERCP, endoscopy of the bile duct and pancreas), which shows "beading" (both strictures and dilation) of the intrahepatic and extrahepatic bile ducts. Another option is magnetic resonance cholangiopancreatography (MRCP), where magnetic resonance imaging is used to visualise the biliary tract.
Most patients with PSC have evidence of autoantibodies. Approximately 80% of patients have perinuclear anti-neutrophil cytoplasmic antibodies, also called p-ANCA; however, this finding is not specific for PSC. Antinuclear antibodies and anti-smooth muscle antibody are found in 20%-50% of PSC patients and, likewise, are not specific for the disease.
Other tests often done are a full blood count, liver enzymes, bilirubin levels (usually grossly elevated), renal function, electrolytes. Fecal fat determination is occasionally ordered when the symptoms of malabsorption are prominent.
The differential diagnosis can include primary biliary cirrhosis, drug induced cholestasis, cholangiocarcinoma, and HIV-associated cholangiopathy.
Read more about this topic: Primary Sclerosing Cholangitis