CT scan findings in a case of<unk> . Ultrasound of sclerosing<unk>  in the common bile duct<unk>  is generally diagnosed on the basis of having at least two of three clinical criteria after secondary causes of sclerosing<unk>  have been ruled out: * serum alkaline phosphatase (ALP) > 1.5x the upper limit of normal for longer than 6 months * cholangiography demonstrating biliary strictures or irregularity consistent with<unk>  * liver biopsy consistent with<unk>  (if available) Historically, a cholangiogram would be obtained via endoscopic retrograde cholangiopancreatography (ERCP), which typically reveals "beading" (alternating strictures and dilation) of the bile ducts inside and/or outside the liver. Currently, the preferred option for diagnostic cholangiography, given its noninvasive yet highly accurate nature, is magnetic resonance cholangiopancreatography (MRCP), a magnetic resonance imaging technique. MRCP has unique strengths, including high spatial resolution, and can even be used to visualize the biliary tract of small animal models of<unk> . Most people with<unk>  have evidence of autoantibodies and abnormal immunoglobulin levels. For example, approximately 80% of people with<unk>  have perinuclear antineutrophil cytoplasmic antibodies (P-ANCA); however, this and other immunoglobulin findings are not specific to those with<unk>  and are of unclear clinical significance/consequence. Antinuclear antibodies and anti-smooth muscle antibody are found in 20-50% of<unk>  patients, and likewise are not specific for the disease,but may identify a subgroup of<unk>  patients who also have autoimmune hepatitis (i.e.<unk> -AIH overlap syndrome). The first autoantibody that was identified as a prognostic marker in<unk>  is the IgA isotype of anti-GP2 antibody. The role of anti-GP2 IgA in<unk>  was simultaneously investigated and reported by two research groups, and later confirmed by others. Association was demonstrated between anti-GP2 IgA and progressive liver fibrosis, cholangiocarcinoma development and shorter transplantation free survival in<unk>  patients. Other markers which may be measured and monitored are a complete blood count, serum liver enzymes, bilirubin levels (usually grossly elevated), kidney function, and electrolytes. Fecal fat measurement is occasionally ordered when symptoms of malabsorption (e.g., gross steatorrhea) are prominent. The differential diagnosis can include primary biliary<unk>  (formerly referred to as primary biliary cirrhosis), drug-induced cholestasis, cholangiocarcinoma, IgG4-related disease, post-liver transplantation nonanastomotic biliary strictures, and HIV-associated cholangiopathy.<unk>  and primary biliary<unk>  are distinct entities and exhibit important differences, including the site of tissue damage within the liver, associations with IBD, which includes ulcerative colitis and Crohn's disease, response to treatment, and risks of disease progression. Classification<unk>  is typically classified into three subgroups based on whether the small and/or large bile ducts are affected. The subgroups of<unk>  include: * Classic<unk>  * Small-duct<unk>  *<unk>  associated with autoimmune hepatitis
Primary sclerosing cholangitis
Autoimmune hepatitis
Secondary sclerosing cholangitis
Fatty liver disease
Primary biliary cholangitis
Alcoholic hepatitis
Ischemic hepatitis
Progressive familial intrahepatic cholestasis