Arteriovenous fistula and portal hypertension in a child with Down syndrome.

• Vol 9 • November 2007 Hepatic AVF in a Child with Down Syndrome The normal pressure in the portal vein is low due to the minimal vascular resistance in the hepatic sinusoids. Increased resistance to blood flow can occur at three levels: a) pre-sinusoidal (e.g., portal vein thrombosis), b) sinusoidal (e.g., liver cirrhosis), and c) post-sinusoidal (e.g., BuddChiari syndrome). Portal hypertension also may arise from increased blood flow (e.g., massive splenomegaly or arteriovenous fistulas), but this is controlled by the low outflow resistance of the normal liver. Thus, hepatic arteriovenous fistula is a rare cause of portal hypertension and gastrointestinal bleeding. Hepatic vascular malformation usually occurs secondary to trauma [1], percutaneous interventions, neoplasms, and cirrhosis. It may also be congenital (e.g., Osler-Weber-Rendu syndrome), most likely due to AVF. It may be asymptomatic or present with features of portal hypertension, such as variceal bleeding, ascites, splenomegaly, diarrhea or heart failure. We describe a child with trisomy 21 (Down syndrome) and AVF associated with extrahepatic portal hypertension and gastro intestinal bleeding. Treatment con sis ted of percutaneous transvascular em bo lization of the AVF.