Venous Occlusive Disease

• Venous occlusive disease occurs when a blockage occurs in the microscopic veins of the liver. Hepatic venous occlusive disease (VOD) is marked by fluid retention in the abdomen, an increased size of the liver and also deterioration in the functioning of the brain in extreme cases.
  
  

Causes

• There are various causes for this disease. Few of the prominent are intake of pyrrolizidine alkaloids, found in crotalaria and senecio plants that are used for making herbal tea and other herbs such as comfrey, use of drugs such as cyclophosphamide and azathioprine that occasionally may have toxic effects on the liver, radiation therapy that is used for suppressing the immune system before a stem cell or bone marrow transplant, or a reaction known as graft-versus-host disease, which may occur after a bone marrow or stem cell transplant. In this, the white blood cells of the newly transplanted tissue attack the recipient's tissues and this reaction occurs in about 3 weeks after the transplant.
  
  

Symptoms of Veno-Occlusive Disease

• Symptoms in this disease may occur quite suddenly. The liver tends to enlarge and become tender. The abdomen swells because of fluid accumulation. The eye whites and skin may turn yellow leading into a condition known as jaundice.
  
  Varicose veins of the esophagus could rupture causing bleeding, sometimes so very profusely that it could cause patients to vomit blood and frequently get into a state of shock. The blood could pass the digestive system, causing the stools to turn black and bad-smelling. This condition is known as melena.
  
  Some also experience a failure in liver functioning and deterioration of the brain function known as hepatic encephalopathy, resulting in coma. Others could also develop cirrhosis, depending on cause and constant exposure to toxic substances.
  
  

Diagnosis

• A Doppler ultrasonography is useful in diagnosing this disease. Occasionally, other invasive tests may be required while a liver biopsy and measuring the blood pressure of the portal and hepatic veins becomes necessary.
  
  

Treatment

• As there is no precise treatment for this kind of blockage, the causes need to be eliminated. Ursodeoxycholic acid helps prevent the occurrence of this disease after a stem cell or bone marrow transplant. A diet low in sodium and diuretics keeps fluids from accumulating in the stomach. An alternate blood flow route that bypasses the liver may have to be created by surgery. A liver transplant may become required in extreme cases.