Causes of Noncirrhotic Portal Hypertension Budd Chiari Syndrome

Definition

Budd-Chiari syndrome is a constellation of signs and symptoms resulting from hepatic venous outflow obstruction. It encompasses all causes of obstruction between the hepatic venules and right atrium, but excludes the sinusoidal obstruction syndrome (SOS, formerly known as hepatic veno-occlusive disease) and all cardiac causes.

Primary Budd-Chiari results from a venous endoluminal web or thrombosis of the outflow veins. In secondary Budd-Chiari the cause of obstruction does not originate in the affected vein. The most common cause of Budd-Chiari is an underlying hypercoagulable state. However, in 25% of the cases in the United States, no underlying cause is found (idiopathic).

Presentation

The clinical presentation of acute Budd-Chiari syndrome includes any combination of ascites, abdominal pain, edema, hepatomegaly and less commonly GI bleeding. Subclinical Budd-Chiari can also be found incidentally during workup of patients with hypercoagulable states. Thus the reported natural history of the disease is skewed towards the most severe forms. In a minority of patients venous outflow obstruction may lead to liver failure and be complicated by encephalopathy, elevated liver function tests, jaundice, and even death. There is also evidence that a small fraction of patients with cryptogenic cirrhosis may have an insidious chronic form of the disease.

Evaluation

The diagnosis of Budd-Chiari can easily be established once the entity is suspected and the proper diagnostic test performed. All three cross-sectional imaging modalities (computed tomography [CT], magnetic resonance imaging [MRI], and ultrasound) can be used to diagnose the disease but the standard diagnostic technique is the hepatic venogram. In the case of Budd-Chiari, contrast injection into any hepatic vein reveals many small branching vessels ("spider's-web") instead of the main hepatic veins. MRI and CT generally show a filling defect in the intra- or suprahepatic inferior vena cava, hepatomegaly with an enlarged caudate lobe, and signal/density changes in a geographic manner. Ultrasound shows no flow in the affected veins. If the diagnosis remains in doubt, liver biopsy should be performed to confirm the diagnosis. A transjugular approach is typically favored over a percutaneous one if ascites or abnormal coagulation profile are present.

Management

In the absence of conclusive studies most experts agree on a stepwise approach to the treatment of Budd-Chiari that depends on disease severity. In asymptomatic patients, and when there is no significant liver dysfunction, initial treatment should be limited with emphasis on treating the underlying cause. In the absence of contraindications, anticoagulation should be the first line of therapy. This however has met with limited success because the underlying hypercoagulable state usually results in recurrent thrombosis. In the case of hemato-logic disorders such as paroxysmal nocturnal hemoglobinuria, thrombolysis of hepatic vein clot should be closely timed with bone marrow transplant to prevent rethrombosis. Without definitive treatment most patients will progress to liver failure and will likely die within 1 to 2 years. Intensive supportive care is generally required then with diuretics, abdominal paracentesis, and endo-scopic treatment of variceal bleeding as the severity of the disease increases. In the absence of a satisfactory response, more invasive intervention may be required. In selected cases, such as short-segment recent thromboses or hepatic venous web, percutaneous transluminal angioplasty with or without stenting combined with thrombolysis can be attempted. Such interventions may be ineffective either because of failure of thrombolysis or because of recurrence due to the underlying hypercoagulable state. In such cases a more definitive approach is necessary. If the disease is rapidly progressive, liver transplantation should be given priority, which provides a 5-year survival of approximately 75%. If on the other hand, liver function is adequate and stable, portocaval shunting is a viable alternative. The surgical option, mesocaval shunt, may not be technically feasible in case of inferior vena cava obstruction. The radiological option, placement of a transjugular intrahepatic portosystemic shunt (TIPS), offers a simpler and safer alternative. It is however technically challenging if there is complete thrombosis of the hepatic vein. Although, long term benefits are at best limited with either shunting technique, the greatest benefit of shunting may be delaying the need for liver transplantation.

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