Primary biliary cholangitis (PBC) is a long-term liver disease involving the progressive destruction of the small bile ducts within the liver. Bile, a fluid produced by the liver for digestion and waste removal, builds up when these ducts are damaged. This accumulation causes inflammation and scarring of the liver tissue. PBC is an autoimmune disease, where the body’s immune system attacks its own healthy cells. The name was changed from primary biliary cirrhosis because the inflammation of the bile ducts (cholangitis) occurs long before significant scarring (cirrhosis) develops.
Causes and Risk Factors
The exact cause of primary biliary cholangitis is not fully understood, but it involves a combination of genetic and environmental factors. The immune system’s T cells, which normally fight infections, mistakenly attack the cells lining the small bile ducts in the liver. A person may have a genetic predisposition to PBC, which is then activated by an environmental trigger like an infection or exposure to certain chemicals.
While anyone can develop PBC, certain factors increase the risk. The disease is far more common in women, who account for approximately 90% of all cases. Age is another factor, with most diagnoses occurring between 30 and 60 years old. A family history of PBC also elevates the risk, as it is more common among siblings and in families where one member is affected. Smoking and exposure to some environmental toxins are also potential triggers.
Symptoms and Disease Progression
Many individuals with PBC show no symptoms at diagnosis, often discovering the condition through routine blood tests. When symptoms appear, they develop slowly over 5 to 20 years. The most common initial symptoms are fatigue that is not relieved by rest and itchy skin (pruritus). The itch can be widespread or confined to one area and may worsen at night.
As the disease progresses, other symptoms can emerge. Dry eyes and mouth (Sjögren’s syndrome) are common. Some people experience pain or discomfort in the upper right abdomen, where the liver is located. Small yellow or white bumps, which are deposits of fat, may appear under the skin (xanthomas) or around the eyes (xanthelasmas).
With advancing liver damage, symptoms can include jaundice, a yellowing of the skin and eyes from the liver’s declining ability to process bilirubin. Fluid may also accumulate in the legs and ankles (edema) or in the abdomen (ascites). The progression rate of PBC varies, but without treatment, it can lead to cirrhosis, which is severe liver scarring.
The Diagnostic Process
Diagnosing primary biliary cholangitis involves specific tests, often beginning when routine blood work reveals abnormal liver enzymes, particularly alkaline phosphatase (ALP). If PBC is suspected, doctors will order an antimitochondrial antibody (AMA) test. AMAs are present in the blood of about 95% of people with PBC, making this a reliable indicator of the disease.
Imaging tests are used to support the diagnosis and rule out other conditions. An ultrasound or a magnetic resonance imaging (MRI) scan of the abdomen can visualize the liver and bile ducts. These techniques are used to exclude other causes of liver abnormalities, such as blockages from gallstones or tumors.
In the past, a liver biopsy was a standard part of the diagnostic process. During a biopsy, a small sample of liver tissue is removed and examined. While this test can confirm the diagnosis and determine the extent of liver damage (staging), it is now less common. A biopsy is reserved for cases where the diagnosis is uncertain after blood tests and imaging, or to assess the severity of liver damage to guide treatment.
Medical Treatments and Management
The goals for treating primary biliary cholangitis are to slow disease progression and manage symptoms. The main medication is ursodeoxycholic acid (UDCA), a naturally occurring bile acid that helps improve bile flow from the liver. This improves liver function and can slow the rate of liver damage, especially when started early. If UDCA is not effective enough, a second-line medication like obeticholic acid (OCA) may be prescribed.
Symptom Control
Managing symptoms is a focus of the treatment plan. For itchy skin (pruritus), doctors may prescribe medications like cholestyramine, which binds to bile acids in the intestines. Antihistamines may also provide relief. There are no specific medications for fatigue, so management focuses on lifestyle adjustments like pacing daily activities. Dry eyes and mouth can be managed with artificial tears and saliva substitutes.
Lifestyle adjustments are recommended to support liver health. Patients are advised to eat a balanced diet and limit alcohol consumption. Because the liver processes many substances, individuals with PBC should discuss all new medications, including over-the-counter drugs and supplements, with their doctor to avoid liver strain.
Associated Health Complications
Primary biliary cholangitis can lead to several health complications. A primary complication is cirrhosis, which is severe and permanent scarring of the liver. This scarring can cause portal hypertension, an increase in blood pressure within the portal vein that carries blood to the liver.
Another complication is osteoporosis, where bones become weak and brittle. This occurs because PBC can interfere with the body’s ability to absorb vitamin D and calcium. The disease can also lead to deficiencies in other fat-soluble vitamins, including A, E, and K, due to impaired bile flow. In cases of severe liver damage leading to liver failure, a liver transplant is the definitive treatment.