Hepatic veno-occlusive disease

Hepatic veno-occlusive disease or veno-occlusive disease (VOD) is a condition in which some of the small veins in the liver are blocked. It is a complication of high-dose chemotherapy given before a bone marrow transplant (BMT) and is marked by weight gain due to fluid retention, increased liver size, and raised levels of bilirubin in the blood.^[1] The name sinusoidal obstruction syndrome is now preferred if VOD happens as a result of chemotherapy or bone marrow transplantation.^[1][2]

Apart from chemotherapy, VOD may also occur after ingestion of certain plant alkaloids such as pyrrolizidine alkaloids (in some herbal teas),^[1] and has been described as part of a rare hereditary disease called hepatic venoocclusive disease with immunodeficiency (which results from mutations in the gene coding for a protein called SP110).^[3]

Signs and symptoms

Features of VOD include weight gain, tender hepatomegaly, ascites, and increased bilirubin. It often is associated with renal failure.

Diagnosis

Hepatic doppler ultrasound is typically utilized to confirm or suggest the diagnosis. Most common findings on liver doppler ultrasound include increased phasicity of portal veins with eventual development of portal flow reversal. The liver is usually enlarged but maintained normal echogenicity. A liver biopsy is required for a definitive diagnosis.

Pathophysiology

In the BMT setting, VOD is felt to be due to injury to the hepatic venous endothelium from the conditioning regimen.

Toxic agents causing veno-occlusive disease include plants as well as the medication cyclophosphamide.

Treatment

Treatment for VOD is primarily supportive. In the BMT setting, defibrotide is an investigational treatment that may be promising. Defibrotide is a polydeoxyribonucleotide isolated from pig intestine. Although its mechanism of action in VOD is unclear, the drug is believed to have antithrombotic properties. In August 2009, Gentium S.p.A., which sponsored the phase 3 clinical trial (pivotal) of defibrotide in hepatic VOD, announced disappointing results. Further clinical development of defibrotide for this indication is uncertain.

Prognosis

When associated with bone marrow transplant, VOD is fatal in over 30% of cases. Cases due to plant alkaloids often have a longer and more unpredictable course.

History

The first report on veno-occlusive disease, in 1920, was as a result senecio poisoning in South Africa.^[4] Subsequent reports were mostly in Jamaicans who had consumed herbal teas.^[1] With the advent of bone marrow transplanation, most later reported cases have been in those undergoing treatment for leukemia.^[1]

See also

• Budd-Chiari syndrome (liver vein obstruction due to thrombosis)

References

Further reading

• Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease. St. Louis, Mo: Elsevier Saunders. ISBN 0-7216-0187-1. 
• Wingard JR, Nichols WG, McDonald GB (2004). "Supportive care". Hematology Am Soc Hematol Educ Program 1: 372–89. doi:10.1182/asheducation-2004.1.372. PMID 15561693. http://asheducationbook.hematologylibrary.org/cgi/content/full/2004/1/372.