Budd-Chiari syndrome, or hepatic venous outflow obstruction, is a rare disorder that causes a narrowing or blockage of the veins in the liver. It slows blood flow out of the liver, potentially causing pain and liver damage.

A clot blocking the vein is the most common cause of Budd-Chiari syndrome in Western nations. Many conditions — such as clotting disorders, trauma, infection, certain medications, and tumors — can cause blood clots.

Budd Chiari syndrome is not necessarily a sign of underlying liver disease. However, it usually occurs secondary to something else, such as a medical condition or pregnancy. Only 20% of cases occur without a clear cause.

Read on to learn more about Budd-Chiari syndrome, including the symptoms, causes, and treatment.

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Budd-Chiari syndrome is a rare condition that affects the flow of blood out of the liver. It results from the narrowing or blockage of a vein in the liver. Usually, a blood clot is the cause.

Because Budd-Chiari syndrome happens infrequently, it is difficult for scientists to collect data on how often the condition occurs. A 2019 meta-analysis estimates a pooled annual incidence rate of 0.469 per million in Asia and 2 per million in Europe.

Doctors usually classify Budd-Chiari syndrome based on how quickly symptoms appear and how severe they are. The main types are:

  • Acute: In this type, the symptoms develop quickly, usually within several weeks, and include worsening symptoms of liver failure.
  • Subacute: This form develops slightly more slowly than the acute form, taking up to 3 months to cause symptoms.
  • Chronic: This type usually occurs with liver cirrhosis. A person may have underlying liver disease.
  • Fulminant: This form can occur with sudden, severe liver failure and may be immediately life threatening.

Some people experience no symptoms of Budd-Chiari syndrome at first, especially in mild or chronic cases. When symptoms do appear, they are similar to other symptoms of liver disease.

They may include:

  • tenderness in the upper abdomen
  • vomiting
  • nausea
  • mild jaundice, which can make the skin or eyes look yellow
  • fatigue

In 80% of cases, Budd-Chiari syndrome has an identifiable cause. The most common causes include:

  • Myeloproliferative disorders: These disorders cause the body to make too many red blood cells, increasing the risk of blood clots. Myeloproliferative disorders account for nearly half of all Budd-Chiari syndrome cases.
  • Oral contraceptives: Taking birth control pills increases the risk of blood clots.
  • Pregnancy: Pregnancy increases the risk of blood clots and, in some cases, may reveal an underlying clotting disorder. Together, oral contraceptives and pregnancy account for 20% of Budd-Chiari cases.
  • Cancer: Cancer may put pressure on the blood vessels of the liver. Alternatively, cancerous cells may travel to these vessels and block them. In total, various types of cancer account for 10% of Budd-Chiari syndrome cases.
  • Liver injuries and infections: Lesions and infections of the liver may increase the risk of a blockage.

The following health conditions also raise the risk of blood clots:

  • connective tissue disease
  • inflammatory bowel disease
  • radiation exposure
  • arsenic exposure
  • sepsis

Although blood clots are a common cause, people can also develop Budd-Chiari syndrome as a result of the growth of fibrous tissue that narrows or blocks a blood vessel.

This could be due to an anatomical difference that occurs in childhood but may also have links to the consumption of pyrrolidizine plant alkaloids. These are chemicals that certain plants contain, including bush tea, which is a popular drink in some parts of the world.

In cases where doctors cannot identify a cause, they refer to the condition as idiopathic Budd-Chiari syndrome.

If a doctor suspects Budd-Chiari syndrome, they will begin by taking a detailed medical history. They may order:

  • blood tests to check liver enzyme levels
  • medical imaging scans to see the blood vessels of the liver, such as an ultrasound, MRI, or CT scan
  • a liver biopsy, if they think that a person may have cirrhosis or cancer

Blood tests will typically show unusual liver enzyme levels and may show that a person is at risk for blood clots. A doctor may find signs of liver cirrhosis, liver failure, or an enlarged spleen, depending on the cause of the condition.

The main goal of treatment for Budd-Chiari syndrome is to clear the blockage that is causing the problem or widen blood vessels that have narrowed. This may involve:

  • prescribing blood thinners such as heparin and warfarin
  • placing a stent to help the blood vessel drain
  • performing thrombolysis, which is a minimally invasive procedure to remove or shrink blood clots
  • performing surgery to remove blood clots or widen veins

If a person has acute Budd-Chiari syndrome that does not respond to treatment, a doctor may recommend placing a transjugular intrahepatic portosystemic shunt. This is an artificial blood vessel that creates a connection between the vein going into the liver and the vein going out, allowing blood to keep circulating.

In addition to restoring blood flow, a doctor will treat any underlying conditions that contribute to Budd-Chiari syndrome. If a person’s condition progresses to liver failure, they may need a liver transplant.

Budd-Chiari syndrome can be life threatening. Most people with the condition will die within 3–5 years If they do not receive treatment for the blocked vein.

The prognosis is worse if a vein is completely blocked. If a person does not receive treatment, a partially blocked vein will shorten life expectancy, but survival depends on many factors. If a doctor can unblock the vein, the outlook is generally better.

Certain factors increase the chances of a good outlook with treatment, such as:

  • younger age
  • low serum creatinine
  • a lower Child-Pugh score, which is an estimate of liver disease severity
  • the absence of ascites, which is abdominal swelling

The cause of the syndrome is also important. For example, someone with advanced cancer may have a shorter survival time even with treatment for Budd-Chiari syndrome, while a person who has a clot due to taking oral contraceptives may make a full recovery once they receive treatment and stop taking the drug.

People who receive liver transplants may also have a different life expectancy. Previous studies have recorded 10-year survival rates of 69–84% after a liver transplant.

Budd-Chiari syndrome is a rare medical condition that occurs when the vein that takes blood out of the liver develops a blockage or becomes narrow. Often, the cause is a blood clot.

With treatment, it is possible to reverse Budd-Chiari syndrome and reduce the risk of liver damage. However, a person’s survival depends on how effective treatment is, their overall health, and the underlying cause of the syndrome.

A person who has Budd-Chiari syndrome should work with a specialist to identify the best treatment options and diagnose any potential underlying causes of the syndrome.