Biliary Strictures

What is a biliary stricture?

A biliary stricture is the narrowing beyond normal of part of the ducts that carry the bile produced in the liver to the bowel.

Bile is produced in the liver and reaches the small bowel through the bile ducts. It helps particularly with the digestion and absorption of fats.

When a significant narrowing develops in a bile duct, the flow of bile into the bowel may become difficult or be blocked entirely. Bile may then build up in the liver and cause symptoms such as jaundice, itching, dark urine and pale stools.

The site, the length and the cause of the stricture can vary from patient to patient.

Why does a biliary stricture matter?

When a stricture is found in a bile duct, the most important question is this:

“What is the cause of this stricture?”

Because biliary strictures can arise from both benign and malignant diseases.

So “a stricture in the bile duct” on imaging does not on its own amount to a diagnosis of cancer.

But a new stricture of unexplained cause in particular must be investigated carefully.

What are the causes of benign biliary strictures?

Strictures developing after an operation

Damage or scarring can develop in the bile duct after operations in the regions near the bile ducts.

A stricture can appear particularly after certain gallbladder and bile duct operations.

Such a stricture may be noticed shortly after the operation, or may appear months or years later.

Chronic pancreatitis

The bile duct passing through the head of the pancreas can be narrowed by the inflammation and fibrosis that develop in chronic pancreatitis.

Obstruction of the bile duct and jaundice can therefore develop in some patients with chronic pancreatitis.

Primary sclerosing cholangitis (PSC)

PSC is a chronic disease that can cause inflammation, narrowing and, over time, scarring in the bile ducts.

More than one stricture may develop in different parts of the bile ducts.

PSC can be seen in some patients together with ulcerative colitis and other inflammatory bowel diseases.

IgG4-related disease

IgG4-related sclerosing cholangitis can cause a stricture in the bile ducts, and can sometimes be confused with cholangiocarcinoma.

It may be found together with autoimmune pancreatitis.

Distinguishing these diseases from one another is important, because their treatments are entirely different.

Other benign causes

Strictures in the bile ducts can also be caused by:

• Previous infections,
• Injury,
• Certain endoscopic or surgical procedures,
• Long-standing inflammation,
• Certain rare diseases.

What are the causes of malignant strictures?

A biliary stricture can also develop because of certain cancers.

Chief among these are:

Cholangiocarcinoma

This is cancer arising from the bile ducts.

According to where the tumour lies it can affect the bile ducts within or outside the liver.

Pancreatic cancer

Tumours developing in the head of the pancreas in particular can press on the main bile duct passing through it and cause narrowing and obstruction.

One of the important symptoms of this may be jaundice.

Other tumours

Cancer of the gallbladder and certain neighbouring tumours can also create a stricture by pressing on the bile ducts or by involving them directly.

What are the symptoms of a biliary stricture?

Depending on the degree of the stricture there may be no symptoms at all, or marked obstruction of the bile duct may develop.

The symptoms most often seen are:

• Yellowing of the eyes and skin,
• Darkening of the urine,
• Paling of the colour of the stool,
• Itching,
• Upper abdominal pain,
• Loss of appetite,
• Nausea,
• Weakness.

According to the cause of the stricture there may be other symptoms too, such as weight loss.

Why does jaundice develop?

Bile contains a yellow substance called bilirubin.

When the bile duct is seriously narrowed, bilirubin cannot be passed into the bowel in sufficient quantity and begins to build up in the blood.

Yellowing may then be seen first in the whites of the eyes and later in the skin.

At the same time the urine may darken, because bilirubin is excreted in it.

Less bile reaching the bowel causes the normal brown colour of the stool to become paler.

Why does a fever matter?

Infection developing in an obstructed bile duct is called acute cholangitis.

The combination of:

fever + jaundice + right upper abdominal pain

in particular may suggest infection of the bile duct.

Severe cholangitis is a condition that can threaten life and may need emergency treatment.

Alongside antibiotic treatment, some patients may need the obstructed bile duct to be opened urgently with ERCP.

How is a biliary stricture recognised on blood tests?

Where the flow of bile is obstructed, the blood tests may show a rise particularly in:

• Alkaline phosphatase (ALP),
• Gamma-glutamyl transferase (GGT),
• Bilirubin.

A rise in AST and ALT may also be seen.

But blood tests do not on their own show the cause of the stricture.

What does ultrasound show?

Ultrasound may be one of the first imaging methods used, particularly in patients presenting with jaundice.

It can show whether the bile ducts are dilated and whether there are stones in the gallbladder.

But it cannot always establish the exact cause of the stricture.

Further imaging methods may then be needed.

What is MRCP and why is it done?

MRCP (magnetic resonance cholangiopancreatography) is a non-invasive method that uses MR technology to image the bile and pancreatic ducts in detail.

MRCP can assess:

• The site of the stricture,
• Its length,
• Dilatation of the bile ducts,
• Whether stones are present,
• Other changes in the bile and pancreatic ducts.

The important advantage of MRCP is that it needs no endoscopic procedure.

Why is an EUS done?

Endoscopic ultrasound (EUS) allows detailed assessment particularly of the parts of the bile duct near the pancreas and of the surrounding tissues.

EUS can assess at high resolution:

• Small tumours in the head of the pancreas,
• Masses in or around the bile duct,
• Lymph nodes,
• Certain small stones in the bile duct.

Where it is thought necessary, a tissue sample can be taken from a suspicious mass or lymph node.

What is ERCP and when is it needed?

ERCP (endoscopic retrograde cholangiopancreatography) is an interventional method that allows the bile and pancreatic ducts to be reached endoscopically.

Today ERCP is mostly used not merely for imaging but for treatment and, where needed, sampling.

During ERCP:

• The stricture in the bile duct can be imaged,
• A cell or tissue sample can be taken from the stricture,
• A stent can be placed to restore the flow of bile,
• Stones within the duct can be removed where necessary.

Are MRCP, EUS and ERCP the same thing?

No. These methods complement one another rather than being alternatives to one another.

MRCP: allows the bile ducts to be imaged without any procedure.

EUS: allows the bile duct, the pancreas and the surrounding structures to be examined very closely, and a tissue sample to be taken where needed.

ERCP: is used particularly to open an obstructed bile duct, to place a stent, and in some situations to take a sample.

Which method is used first is decided according to the patient’s situation.

Can a biopsy be taken from a biliary stricture?

Yes.

In a biliary stricture of uncertain cause, benign and malignant causes may need to be distinguished from one another.

Brush cytology or a biopsy can be taken from the stricture during ERCP.

During EUS, sampling with a needle can be carried out particularly where there is a surrounding mass or a suspicious lymph node causing the stricture.

In some specialist centres it may also be possible to take a targeted biopsy from the suspicious area using cholangioscopy, which images the inside of the bile duct directly.

If the biopsy is negative, is cancer definitely excluded?

Not always.

Sampling in biliary strictures can sometimes be technically difficult, and the sample obtained may not contain enough cells.

For this reason a negative result may not be enough on its own where the imaging, the clinical findings and the other tests are strongly suspicious.

Some patients may need repeat sampling or assessment by a different method.

Can CA 19-9 be used?

CA 19-9 is a tumour marker that may be raised in some cancers of the pancreas and the bile ducts.

But CA 19-9 can also be raised where the bile duct is obstructed by benign causes, and in cholangitis in particular.

For this reason:

a high CA 19-9 = definitely cancer

does not hold.

Equally, a normal CA 19-9 value does not definitely exclude cancer.

The result must always be assessed together with the other findings.

Why is a stent placed in the bile duct?

If the bile duct is seriously narrowed or obstructed, a stent can be placed at the site of the stricture during ERCP to restore the flow of bile into the bowel.

The stent acts like a small tube and keeps the narrowed area open.

This way:

• The jaundice may lessen,
• The itching may settle,
• The risk of infection of the bile duct may be reduced,
• In some patients it may become easier to give the treatments that follow.

What is the difference between a plastic and a metal stent?

Different kinds of stent can be used in the bile ducts.

Plastic stents are preferred in certain situations and mostly have to be changed or removed after a set period.

Self-expanding metal stents can provide a wider diameter and may be used particularly in some situations needing long-term drainage.

Which stent is used is decided according to the cause and the site of the stricture and the treatment planned.

Can benign biliary strictures be treated?

Yes.

Treatment varies with the cause of the stricture.

In some benign strictures, balloon dilatation and temporary stents at ERCP may be used.

Some patients may need more than one ERCP session.

Where endoscopic treatment is not sufficient or is not anatomically suitable, surgical treatment may come into consideration.

What is done for malignant strictures?

Treatment is planned according to the kind of cancer, its site, its stage and the patient’s general condition.

Surgical treatment may be possible in suitable patients.

Where an operation is not possible, or where biliary drainage is needed before an operation, a stent may be placed in the bile duct by ERCP or by other methods.

Oncological treatment is planned separately according to the kind of disease.

Do biliary strictures recur?

Yes.

Narrowing can develop again after endoscopic treatment, particularly in some benign strictures.

For this reason it matters that patients who have had a stent placed, or who have been treated for a stricture, do not miss their follow-up appointments.

If the stent is planned to be changed or removed, that date must not be forgotten.

When is emergency assessment needed?

In a person with a biliary stricture, if there develops:

• Fever and shivering,
• A rapid increase in the jaundice,
• Severe right upper abdominal pain,
• Persistent vomiting,
• Low blood pressure,
• A change in consciousness or a marked deterioration in general condition,

acute cholangitis or serious obstruction of the bile duct may be present.

Emergency medical assessment is then needed.

Remember

A biliary stricture is less a diagnosis than a finding that may have different diseases beneath it.

Seeing a biliary stricture does not always mean cancer. Benign causes such as changes after an operation, chronic pancreatitis, PSC and IgG4-related disease can also lead to a stricture.

Even so, malignant diseases such as pancreatic cancer and cholangiocarcinoma also have to be excluded.

MRCP, EUS and ERCP are complementary methods in making the diagnosis.

Today the most important role of ERCP is not merely to make a diagnosis, but to take a sample where needed, to open an obstructed bile duct and to place a stent.

The development of fever and abdominal pain together with jaundice in particular may require emergency assessment.