Primary biliary cirrhosis

Summary

• In primary biliary cirrhosis, the bile ducts of the liver are damaged, obstructing the flow of bile.
• The exact cause is unknown, but it is probably an autoimmune disorder.
• It develops slowly and is more common in women than men.
• It can lead to cirrhosis, with potentially life-threatening complications.
• There is no cure, but medication can reduce symptoms and slow the disease.
• Eventually liver transplant may become necessary.

Alternative names

PBC

What is primary biliary cirrhosis?

Primary biliary cirrhosis (PBC) is a disease in which the bile ducts of the liver become inflamed and damaged, obstructing the flow of bile from the liver.

Bile helps digest fats and rids the body of waste substances like old blood cells, cholesterol and toxins. When the bile ducts are destroyed, these substances build up, damaging liver cells and eventually causing cirrhosis (scarring). Cirrhosis affects the liver's functioning and can lead to liver failure.

The disease is gradual, usually being diagnosed between the ages of 30 and 60. It affects more women than men. The outcome varies, but in advanced cases it can be life-threatening.

What causes primary biliary cirrhosis?

The precise cause is not known. PBC is probably an autoimmune disease, in which the immune system attacks the body's own cells. Other factors may also be involved:

• PBC seems to run in families, and so there may be a genetic component.
• Infection by bacteria, fungus, parasites or retroviruses may possibly be implicated.

What are the symptoms of primary biliary cirrhosis?

The onset is gradual, often over years. Many people do not have symptoms in the early stages. Usually the initial symptom is skin itching, often in the arms, legs and back. This may be accompanied by:

• Fatigue
• Dry eyes and mouth

Other symptoms may develop more gradually:

• Jaundice (yellowing of the whites of the eyes and the skin)
• Darkened or blotchy skin
• Fatty deposits under the skin, especially around eyes and eyelids
• Fluid retention, especially in ankles and abdomen
• Enlarged liver
• Abdominal pain
• Diarrhoea and fatty stools
• Vitamin deficiencies, especially fat-soluble vitamins A, D, E and K
• Urinary tract infections
• Osteoporosis (bone softening and fragility)
• Arthritis
• Thyroid problems
• Renal stones or gallstones

How is a diagnosis made?

Often, patients are diagnosed incidentally after unrelated blood tests or medical examination.

Further tests confirm the diagnosis:

• Blood may show elevated levels of certain liver enzymes, cholesterol , lipoproteins and immunoglobulin M.
• A liver biopsy (where a small tissue sample is examined) may show abnormalities.
• In 95% of people with PBC, specific mitochondrial antibodies are present in the blood.
• Scans - ultrasound, or magnetic resonance elastography (MRE) - can detect liver abnormality.
• ERCP or PTC - X-ray techniques which involve injecting dye into the bile duct - may be used to evaluate blockage.

How is it treated?

No cure exists and damage to the liver is irreversible. However, treatment may slow the progress of the disease, alleviate symptoms and reduce or prevent complications.

• Itching may be reduced with various drugs.
• Artificial tears can relieve dry eyes.
• Daily doses of Ursodeoxycholic acid (UDCA) may improve functioning of the liver.
• Vitamin deficiencies can be rectified with supplements.
• Calcium and vitamin D supplements can reduce the weakening of bones.
• Obstructed bile ducts can be drained through an endoscope during the ERCP process.
• When treatment is no longer effective and the liver begins to fail, a liver transplant may be necessary.

Maintaining general health - following a healthy diet, exercising, reducing alcohol consumption, drinking plenty of water and reducing stress - will improve a patient's overall sense of well-being and may alleviate certain symptoms.

What is the prognosis?

The outcome of PBC is extremely variable. Patients may remain relatively healthy and even symptom-free for years after diagnosis. If they receive treatment while the liver is still functioning well, their life expectancy may be normal.

However, if the condition is untreated, most patients will need a liver transplant (usually about seven years after diagnosis). These operations are generally successful, although in some cases PBC may recur.

Complications

Complications may be severe and life-threatening, especially if cirrhosis has set in. As liver damage progresses, patients may develop a number of serious problems, including:

• Increased pressure in the portal vein (leading into the liver), due to scar tissue obstructing the circulation.
• Blood backing up into other veins. These veins become enlarged, and can rupture and bleed into the upper stomach or oesophagus - a medical emergency.
• A greatly increased risk of liver cancer.
• Increased risk for other metabolic or immune system disorders.

Several drugs to treat PBC have unpleasant side effects and may be difficult or inconvenient to take.

When to call your doctor

Call your doctor if you have unexplained skin itching, or if you develop any other PBC symptoms.

If you have been diagnosed with PBC, call your doctor urgently if you vomit blood or experience bloody stools , confusion, abdominal swelling or jaundice.

How can it be prevented?

Close relatives of PBC patients are more at risk and can be tested for the antibodies that indicate PBC. If these are detected, treatment can be started early.

Image: Liver anatomy from Shutterstock