Budd–Chiari syndrome

Budd–Chiari syndrome is a very rare condition, affecting one in a million adults. The condition is caused by occlusion of the hepatic veins (usually due to a blood clot) that drain the liver. The symptoms are non-specific and vary widely, but it may present with the classical triad of abdominal pain, ascites, and liver enlargement. It is usually seen in younger adults, with the median age at diagnosis between the ages of 35 and 40, and it has a similar incidence in males and females. The syndrome can be fulminant, acute, chronic, or asymptomatic. Subacute presentation is the most common form. The acute syndrome presents with rapidly progressive severe upper abdominal pain, yellow discoloration of the skin and whites of the eyes, liver enlargement, enlargement of the spleen, fluid accumulation within the peritoneal cavity, elevated liver enzymes, and eventually encephalopathy. The fulminant syndrome presents early with encephalopathy and ascites. Liver cell death and severe lactic acidosis may be present as well. Caudate lobe enlargement is often present. The majority of patients have a slower-onset form of Budd–Chiari syndrome. This can be painless. A system of venous collaterals may form around the occlusion which may be seen on imaging as a "spider's web". Patients may progress to cirrhosis and show the signs of liver failure. The cause of Budd–Chiari syndrome can be found in more than 80% of patients. However, in 20% of cases, there is no underlying cause discovered. These cases are known as idiopathic Budd–Chiari syndrome. In about 75% of cases, there is an underlying hypercoagulability disorder, with a third of these people having two or more hypercoagulable disorders. Primary Budd–Chiari syndrome occurs due to thrombosis of the hepatic vein. The most common cause is due to acquired hypercoagulability associated with myeloproliferative disorders (accounting for 40–50% of cases). Other acquired hypercoagulable disorders that may result in Budd–Chiari syndrome include antiphospholipid syndrome and paroxysmal nocturnal hemoglobinuria, which are responsible for 10–12% and 7–12% of Budd–Chiari syndrome cases, respectively.