Veno-occlusive Disease of the Liver

Veno-occlusive disease of the liver is blockage of the very small (microscopic) veins in the liver.

• Fluid tends to accumulate in the abdomen, the spleen may enlarge, and severe bleeding may occur in the esophagus.
• The skin and whites of the eyes may turn yellow, and the abdomen may enlarge.
• Doctors base the diagnosis on symptoms and results of Doppler ultrasonography.
• If possible, the cause is corrected or eliminated, and symptoms are treated.

Veno-occlusive disease is similar to Budd-Chiari syndrome except that blood flow is blocked within (rather than outside of) the liver. That is, blockages do not affect the large hepatic veins and the inferior vena cava (the large vein that carries blood from the lower parts of the body, including the liver, to the heart).

Veno-occlusive disease may occur at any age. It is more common among people who are malnourished.

Because flow out of the liver is blocked, blood backs up in the liver. This backup (congestion) then reduces the amount of blood entering the liver. Liver cells are damaged because they do not get enough blood (ischemia). The congestion causes the liver to become engorged and enlarged. Such outflow obstruction also is transmitted across the liver, increasing pressure in the portal vein (portal hypertension). Portal hypertension can result in dilated, twisted (varicose) veins in the esophagus (esophageal varices). The elevated pressures in the portal vein and the liver congestion lead to fluid accumulating in the abdomen—a disorder called ascites. The spleen also tends to enlarge.

Such congestion reduces blood flowing into the liver. The resulting liver damage leads eventually to severe scarring (cirrhosis).

Causes

Common causes include the following:

• Ingestion of pyrrolizidine alkaloids, which are found in crotalaria and senecio plants (used in Jamaica to make herbal tea) and in other herbs, such as comfrey
• Use of certain drugs that occasionally have toxic effects on the liver, including cyclophosphamide and azathioprine Some Trade Names
  IMURAN
  (used to suppress the immune system)
• Radiation therapy (used to suppress the immune system before bone marrow or stem cell transplantation)
• A reaction after bone marrow or stem cell transplantation (graft-versus-host disease)

In graft-versus-host disease, white blood cells in the transplanted tissue attack the recipient's tissues. This reaction tends to occur about 3 weeks after transplantation.

Symptoms

Symptoms may begin suddenly. The liver enlarges and becomes tender. The abdomen may swell because of fluid accumulating there. The skin and the whites of the eyes may become yellow—a condition called jaundice.

Varicose veins in the esophagus may rupture and bleed, sometimes profusely, causing people to vomit blood and often go into shock. The blood may pass through the digestive tract, making stools black, tarry, and foul-smelling (called melena). When bleeding is severe, shock ensues. A few may experience liver failure with deterioration of brain function (hepatic encephalopathy), resulting in confusion and coma.

Others develop cirrhosis with time, likely over months, depending upon the cause and repeated exposure to toxic agents.

Diagnosis

Doctors suspect veno-occlusive disease based on symptoms or blood test results that suggest liver dysfunction, particularly if people have ingested substances or have conditions (particularly following bone marrow transplantation) that may cause the disease. Blood tests evaluate the liver and blood clotting.

Doppler ultrasonography often confirms the diagnosis. Occasionally, invasive tests may be necessary. Liver biopsy or blood pressure measurements of the hepatic veins and portal veins rarely are necessary. These are done by inserting a catheter into a vein in the neck (jugular vein) and threading it to the hepatic veins. A biopsy of the liver can be taken at the same time.

Prognosis

The prognosis depends on how extensive the damage is and whether the condition causing it recurs or continues—for example, when people continue to drink senecio tea.

Overall, about one fourth of people with veno-occlusive disease die of liver or other organ failure within 3 months. When the cause is graft-versus-host disease after bone marrow transplantation, veno-occlusive disease often resolves on its own within a few weeks. Increasing the dose of drugs used to suppress the immune system can also cause graft-versus-host disease to resolve. If the cause is an ingested substance, stopping its use helps prevent further liver damage.

Treatment

There is no specific treatment for the blockage. If possible, the cause should be eliminated.

Ursodeoxycholic acid helps prevent veno-occlusive disease from developing after bone marrow or stem cell transplantation.

Problems resulting from the blocked vessels are treated. For example, a low-salt (low-sodium) diet and diuretics help keep fluid from accumulating in the abdomen.

An alternate route for blood flow, bypassing the liver, may be created by directly connecting the portal vein to the inferior vena cava. A catheter is inserted in a neck vein (jugular vein), threaded to the portal vein, and used to make this connection (shunt). Then a wire mesh tube (called a transjugular intrahepatic stent) is inserted to keep the shunt open. The effectiveness of such shunts is unclear.

Liver transplantation may be necessary in extreme cases.

Adapted from: Merck & Co., Inc.