Noncirrhotic portal hypertension in HIV infection

Liver disease in the HAART era is one of the leading causes of morbidity and mortality in HIV-infected individuals in Western countries. Even if the majority of cases rely on identifiable causes (viral hepatitis, steatohepatitis, alcohol abuse, drug toxicity, etc.), the cause of liver abnormalities remains unknown for a subset of patients, some of whom present with noncirrhotic portal hypertension (NCPH).

In 2006, the first reports of NCPH in HIV-infected patients attracted special attention. Typically, individuals unaware of any underlying liver illness presented with variceal bleeding, occasionally fatal. Interestingly, severe portal hypertension occurred in the absence of liver function impairment in most cases. Liver biopsy revealed a distinctive histological feature characterized by massive absence of portal veins along with focal obliteration of small portal veins. After extensive ruling out of other causes, the role of antiretroviral toxicity (particularly didanosine exposure) emerged as the major contributor to this condition. Other potential factors could be an enhanced microbial translocation from the gut and prothrombotic conditions.

NCPH is an uncommon condition, although increasingly being reported in HIV-infected individuals. It generally presents as a clinical episode of decompensated portal hypertension, generally with gastrointestinal bleeding. Long-lasting HIV infection and prolonged antiretroviral exposure are universally recognized in these patients. The involvement of didanosine has been highlighted in most series. Removal of this drug and prevention of variceal bleeding episodes are currently the most effective prophylactic and therapeutic interventions.