Primary sclerosing cholangitis (PSC)
This form of autoimmune liver disease occurs in more than 50% of all cases in combination with an inflammatory bowel disease, especially with ulcerative colitis. Primary sclerosing cholangitis (PSC) leads to an inflammation and scarring of the biliary ducts and hence causes liver cirrhosis in many patients over years or decades. Especially the early detection and therapy of bacterial infections of the affected bile ducts is important, since these infections can accelerate the course of a primary sclerosing cholangitis.
Primary sclerosing cholangitis has no typical clinical signs. Symptoms are non-specific and often occur only in the late course of the disease:
- Fatigue and pruritus
- mild pain in the upper abdomen
These symptoms contribute little to the diagnosis. Specific symptoms can be pain in the upper right abdomen, fever and jaundice, which point at a purulent inflammation of the bile ducts. Cholangiocarcinoma, a malignant tumor of the bile ducts, is another severe consequence of PSC. In about 5 % of the patients this is diagnosed during the first year after diagnosis of PSC, while after the first year it arises only in about 1 %. of cases/year. Hence the continuous surveillance of the course of disease in a specialist centre is important.
Since the symptoms are non-specific and in most cases only occur late in the course of disease, it is often difficult to diagnose PSC. Furthermore, laboratory results may also be non-specific.Therefore, diagnosis of PSC based only on laboratory results is impossible.
- Elevated liver enzymes pointing at bile duct damage (AP, GGT)
- Often findings of auto antibodies (ANCA)
Especially in combination with an inflammatory bowel disease elevated liver enzymes may strongly suggest the presence of PSC. However, this autoimmune liver disease can also occur on its own and is then very difficult to diagnose. In order to diagnose PSC it is necessary to examine the bile ducts employing an imaging technique since the laboratory results are not specific for the disease.
Imaging techniques are magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP). Both these imaging techniques allow detection of constrictions/obstruction and dilatation of bile ducts which occur (irregularly distributed. MRCP is safer since it is non-invasive. However, the bile ducts are often visualized not very clearly. ERCP on the other hand gives a very clear image, and allows treatment of constrictions of the ducts at the same time. Nevertheless, there is a risk of 5 % of transient pancreatitis caused by the examination. On initial diagonsis, a liver biopsy (tissue sample) should be taken in order to get as clear a picture as possible. However, in early stages of the disease the result may be normal as characteristic changes first occur only sporadically in the bile duct system. On the other hand, early stages can often be detected easier in the biopsy than by imaging. In rare cases only the small intrahepatic ducts are effected by PSC (small duct PSC). In this case, imaging shows normal results, but in the biopsy a characteristic, onion-layer like accumulation of connective tissue around the bile ducts can be seen. Patients with this kind of PSC have a very good prognosis.
In most cases, PSC takes a slow but steadily progressive course. There is no treatment that can reliably stop the course.
For many years standard treatment was the administration of the protective bile acid Ursodexoycholic acid. However, new study results show that the effect of this treatment is questionable. It improves laboratory test results, but it is not clear if the course of the disease can be slowed by UDCA. Further development of this drug as well as new drugs are currently tested in clinical trials, and may change standard treatment recommendation for PSC.
In the event of blockages of the bile ducts due to disease-related obstruction these obstructions should be widened by ERCP using balloon dilatation. If a purulent inflammation in the bile ducts occurs, the immediate treatment with antibiotics is indicated since such inflammation can accelerate the course of disease.
In most cases PSC eventually leads to liver cirrhosis requiring liver transplantation. The period between diagnosis and transplantation varies a lot, but in most cases is about 10 to 20 years, sometimes even longer. Treatment of the patients should aim to postpone transplantation for as long as possible while at the same time identify the right moment for transplantation. This is usually the moment when serious complications arise. The fact that a malignant tumor in the bile ducts may possibly occur does not in itself present a reason for early transplantation since the risk of a tumor is (with approx. 1% per year) considerably lower than the risks of transplantation.
Results of liver transplantation due to PSC are good both with regard to the overall survival and the quality of life. Most patients feel healthy and highly productive only a few months after transplantation. Since the disease does also affect the extrahepatic bile ducts a special transplantation technique is often required. The patient’s bile ducts are removed completely and the smaller intestine is sewed directly on the main bile duct of the transplatation organ. This may in some cases lead to problems with the bile ducts of the transplanted liver. Hence, regular control examinations in a specialized centre are necessary.