Primary sclerosing cholangitis

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. Although PSC is often considered to be an autoimmune disease, there may not be universal agreement on this

Signs and symptoms

Severe jaundice with itching
Malabsorption (especially of fat) and steatorrhea, leading to decreased levels of the fat-soluble vitamins, A, D and K.
Signs of cirrhosis
Ascending cholangitis, or infection of the bile duct.

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 cholangiopancreatography (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.

The differential diagnosis can include primary biliary cirrhosis, drug induced cholestasis, cholangiocarcinoma, and HIV-associated cholangiopathy.

Causation

The cause(s) for PSC are unknown. It is often considered to be an autoimmune disorder. It is not, however, in the List of Autoimmune Diseases, and none of the references below clearly identify it as such.

PSC is associated with ulcerative colitis. It is assumed that these diseases share a common cause. Although ulcerative colitis is often treated as an autoimmune disorder, there appears to be no consensus that it actually is such.

Ulcerative colitis is a systemic disease that affects many areas of the body. PSC is often listed as a manifestation of ulcerative colitis outside the colon. PSC differs from these manifestations in that, unlike most other manifestations, PSC continues in spite of surgical removal of the colon.^* This suggests that, while the cause of ulcerative colitis, and most of its manifestations, is in the colon, the cause of PSC is located outside the colon.

Pathophysiology

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.

Epidemiology

It is more prevalent 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.

Screening

PSC is associated with cholangiocarcinoma, which are tumors involving the biliary tree. Screening for cholangiocarcinoma in patients with PSC is encouraged, but there is no general consensus on the modality and interval of choice.

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, ERCP, which may involve stenting of the common bile duct, may be necessary in order to open major blockages (dominant strictures).

Liver transplantation (including live transplants whereby a portion of a living donor is given to the recipient) is an option if the liver begins to fail.

External links

Autoimmune diseases | Gastroenterology | Hepatology | Inflammations

Cholangitis

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