Primary sclerosing cholangitis (PSC) is an inflammatory disease of the bile duct, which leads to cholestasis (blockage of bile transport to the gut). Bile is necessary for the absorption of dietary fat. Blockage of the bile duct leads to accumulation, damages the liver (leading to jaundice) and eventually causes liver failure. PSC is considered an autoimmune disease.
Signs and symptoms
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). Another option is magnetic resonance cholangiopacreaticography (MRCP), where magnetic resonance imaging is used to visualise the biliary tract.
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.
Pathophysiology
The cause(s) for PSC are unknown, but it is considered an autoimmune disorder.
Bile ducts, both intra- and extrahepatically (inside the liver and outside), are inflamed and develop scarring, obstructing the flow of bile. As bile assists in the enteric breakdown and absorption of fat, the absence of bile leads to fat malabsorption. The bile accumulates in the duct, leading to liver cell damage and liver failure.
PSC is associated with ulcerative colitis. It is assumed that these diseases share a common cause.
Epidemiology
It happens more in men than in women. The disease normally starts from age 30 to 60. It can however also start with children. PSC progresses slowly, so the disease can be active for a long time before it is noticed or diagnosed.
Therapy
Standard treatment includes ursodiol, a bile acid naturally produced by the liver, which has been shown to lower elevated liver enzyme numbers in people with PSC, but has not yet been proven effective at prolonging the life of the liver. Treatment also includes medication to relieve itching (antipruritics), antibiotics to treat infections, and vitamin supplements, as people with PSC are often deficient in vitamin A, vitamin D, and vitamin K.
In some cases, surgery to open major blockages in the common bile duct is also necessary. Liver transplantation (including live transplants whereby a portion of a living donor is given to the donee) is an option if the liver begins to fail.
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