Budd-Chiari syndrome is a rare condition resulting from hepatic vein obstruction that leads to hepatomegaly, ascites, and abdominal discomfort. It is most commonly due to a thrombotic occlusion secondary to a chronic myeloproliferative neoplasm (e.g., polycythemia vera), but may be caused by other conditions associated with hypercoagulable states. The obstruction of blood flow causes congestion of the liver with subsequent liver cell damage. If left untreated, it may result in progressive liver failure. Doppler ultrasound confirms the diagnosis. Management involves preventing further clotting with anticoagulation therapy, restoring blood flow with radiologic or surgical procedures, and treating the underlying condition.
Secondary to conditions associated with hypercoagulability (most common) 
- Polycythemia vera (most common cause)
- Paraneoplastic thrombocytosis
- Pregnancy and postpartum period
- Clotting disorders (e.g., factor V Leiden thrombophilia, antiphospholipid syndrome)
- Chronic inflammatory diseases (e.g., Behcet's disease)
- Side effect of medication (e.g., hormonal contraception) 
- Secondary to invasion or compression of the hepatic veins (less common)
- Hepatocellular carcinoma, renal carcinoma
- Chronic infections and hepatic lesions (e.g., amebiasis, aspergillosis, syphilis, tuberculosis)
- Obstruction (e.g., due to thrombosis or compression) of hepatic veins → ↓ blood outflow → hepatic venous congestion → increased sinusoidal pressure, cellular hypoxia, centrilobular necrosis → congestive hepatopathy
- May develop into “nutmeg liver”: Because of ischemia and fatty degeneration, the tissue appears speckled with dark spots.
- Clinical symptoms depend on the extent of hepatic injury and portal hypertension.
- Abdominal pain
- Tender hepatomegaly
- Ascites and abdominal distention
- Signs of increased perfusion of portocaval anastomoses (e.g., esophageal varices, or caput medusae)
- In severe cases: ankle edema, splenomegaly, and renal impairment
In contrast to congestive heart failure, which can also cause hepatic congestion, Budd-Chiari syndrome does not lead to jugular venous distension.
- Blood analysis: often nonspecific findings; possible elevated aminotransferases
Ascites fluid analysis
- WBC count < 500 /μL
- Serum ascites albumin gradient > 1.1 
Imaging (confirmatory test): A visible occlusion of the hepatic vein confirms the diagnosis.
- Doppler ultrasound
- CT, MRI with contrast 
- Treat the underlying disease
- Anticoagulation (to prevent propagation of the thrombus)
Restore blood flow
- Localized thrombolysis
- Balloon angioplasty and stenting
- TIPS (transjugular intrahepatic portosystemic shunt) if complications of portal hypertension occur
- Liver transplantation in the event of liver failure
We list the most important complications. The selection is not exhaustive.