Diagnostic Criteria and Differential Diagnosis

Visualization of the biliary tree is essential for establishing the diagnosis of PSC. ERCP is the diagnostic test of choice, although magnetic resonance cholangiography (MRC) is reasonably sensitive and specific for the detection of PSC and may be a more cost-effective alternative for establishing the diagnosis in patients with suspected PSC. Percutaneous approaches also can be used, but because of the frequently sclerotic intrahepatic bile ducts, gaining access to the intrahepatic biliary system by the percutaneous route can be challenging. The availability of MRC as a screening test for patients with suspected PSC made non-invasive diagnosis possible. The diagnosis criteria for PSC include typical cholangiographic abnormalities involving any part of the biliary tree, compatible clinical and biochemical findings (typically prolonged cholestasis), and exclusion of other causes of secondary sclerosing cholan-gitis, such as previous biliary tract surgery, bile duct neoplasm, acquired immunodeficiency syndrome cholangiopathy, chole-docholithiasis, congenital abnormalities, history of caustic sclerosis of the bile ducts, ischemic strictures after transplantation, or caustic or chemical injury to the bile ducts caused by infusion. Liver biopsy has been used in the past to help confirm the diagnosis, although the diagnostic specificity and sensitivity of the biopsy have come under question, particularly in those patients with typical cholangiographic features of PSC. A liver biopsy with features compatible with PSC in patients with IBD and chronic cholestasis, but a normal cholangiogram, is called small-duct PSC and represents about 5 to 10% of histologically confirmed cases of PSC. Small-duct PSC can progress to classic PSC with typical cholangiographic features in some patients whose cases are followed for several years.

Given the uncertainty of natural history studies, prognostic models based on actual data obtained from patients at a given point in time have been developed to help more accurately predict an individual patient's prognosis. A variety of models have been created; among them, the Mayo risk score is the most widely used. The Mayo PSC risk score is calculated by the following formula:

R = 0.03 (age in years) + 0.54 x log (bilirubin in mg/dL) + 0.54 x log (aspartate aminotransferase [AST] in U/L) + 1.24 (history of variceal bleeding) - 0.84 x (albumin in g/dL)

Thus, a 50-year-old man with a serum bilirubin of 5 mg/dL, an AST of 140 U/L, one prior gastrointestinal bleed, and an albumin of 2.8 g/dL would have a Mayo PSC risk score of 1.92. If this patient had another episode of variceal bleeding, his Mayo risk score would increase significantly, even if all other parameters remained unchanged.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

Get My Free Ebook

Post a comment