What is the bile duct?

The bile ducts are a series of tubes connecting the liver to the small bowel that drain bile from the liver into the gut. They arise as small branches within the liver and progressively join up to form the main bile duct, into which the gallbladder, a sac containing bile situated on the under surface of the liver, also drains. The whole system is often termed the biliary tree.

Gallstones

The most common disorder of the gallbladder or bile ducts is the formation of gallstones. Gallstones are typically made up of cholesterol or bile pigments. They often do not cause symptoms and can be found by chance on scanning the upper abdomen. They can however cause pain in this region together with vomiting. Occasionally gallstones can cause infection of the gallbladder (cholecystitis) or of the bile ducts themselves (cholangitis).

If they cause complete obstruction of the bile duct and impede bile flow this can lead to jaundice or an acute inflammation of the pancreas (acute pancreatitis). These conditions require urgent admission to hospital. Patients will normally require a small operation to remove the gallbladder, called a cholecystectomy, if they have symptomatic gallstones. This is typically key-hole (laparoscopic) surgery performed as a day-case procedure. Gallstones in the bile duct are removed by an endoscopic procedure, called ERCP.

Bile duct blockages

Another very common cause of bile flow blockage is the development of a bile duct narrowing, called a stricture. The most common location of this is the main bile duct and here it will frequently cause complete obstruction and jaundice. There are benign, inflammatory, conditions that can lead to a bile duct stricture, but the most important disease to exclude is the development of a bile duct cancer (cholangiocarcinoma) or a cancer in the head of the pancreas. Obstruction due to a bile duct stricture is normally relieved by the placement of a metal of plastic tube (stent) at ERCP endoscopy, before the cause/origin of the stricture is dealt with.

Cholangiopathy

Generalised diseases that affect the bile ducts or biliary tree over a wide area are termed cholangiopathies. The precise cause of these conditions remains unclear. Their basis is probably autoimmune, in which a person’s own immune system starts to attack certain tissues in the body. Why control of the immune system is lost and why immune cells are targeted towards components of the bile duct are not well understood.

The two most frequently encountered diseases are primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). In both conditions inflammation of the bile ducts can cause damage and bile duct loss leading to poor bile flow, jaundice and impairment of liver function. In some patients, these two diseases may cause progressive damage and scarring of surrounding healthy liver tissue leading to cirrhosis (hyperlink).

Primary Biliary Cholangitis (PBC) was formerly known as primary biliary cirrhosis (PBC). Its name was recently changed as not all patients with PBC will develop cirrhosis. It affects considerably more women than men (90%) and is most common between the ages of 40-70. It is a condition that can sometimes run in families. In PBC, the damage is to the microscopic bile ducts with the liver itself and typical symptoms are itch (pruritus) and fatigue. In advanced disease, jaundice or complications of poor liver function may develop.

There are specific blood tests that will enable your liver specialist to make a diagnosis of PBC, though sometimes a liver biopsy is still required. Patients may often have the abnormality on the blood tests for quite some time before symptoms of the disease occur.

What is the treatment?

PBC is a chronic (long-term) disease, though progression is variable and often only very slow. Many patients are well managed on oral medication such as ursodeoxycholic acid (UCDA), which slows down the progression of the disease and can prevent long-term complications. Not all patients respond to UDCA and new therapies, such as obeticholic acid, are being developed. A small group of patients will go on to require assessment for liver transplantation (hyperlink). Patients with PBC may also be at higher risk of developing thin bones (osteoporosis) and high cholesterol.

Primary Sclerosing Cholangitis (PSC) is an inflammatory disease that typically affects the larger bile ducts within (intra-hepatic) and outside (extra-hepatic) the liver. The ducts can become thickened (sclerosed) and narrowed impeding normal flow of bile. Over time, patients may develop jaundice, bile duct infection (cholangitis) and are at risk of forming gallstones. Equally, the disease can cause progressive damage to the liver. Symptoms can include fatigue, pruritus and upper abdominal pain.

A majority of patients with PSC are men, and it is often diagnosed at a relatively young age (20-45). About two-thirds of people affected also have inflammatory bowel disease (IBD), a chronic inflammatory disorder of the bowel. Ulcerative colitis and Crohn’s disease are two types of IBD. Though mild in some patients, we do know that PSC can unfortunately often run a fairly aggressive course. Overall patients with PSC are at increased risk of developing cancer in their lifetime, particularly of the gallbladder, bile duct (cholangiocarcinoma) and colon. PSC may also sometimes progress to cirrhosis and end-stage liver disease.

How is diagnosis made?

Diagnosis is usually made through a combination of clinical history, blood tests and imaging. A dedicated MRI (MRCP) is the best scan to study the pattern of bile ducts abnormalities and to assess for complications. Occasionally a liver biopsy may be required.

What is the treatment?

Currently there is no cure for PSC. Treatments are centred on the management of symptoms, surveillance for the development of PSC-related complications, and specific interventions for these complications, should they occur. This may include antibiotic therapy to treat infections occurring from within the bile ducts (cholangitis), or ERCP endoscopy to stretch up any large areas of bile duct narrowing or to place a stent. In the minority of patients that go on to develop end-stage cirrhosis, liver transplantation may need to be considered and your specialist will guide and support you through this process (hyperlink).