Budd-Chiari Syndrome
Budd-Chiari syndrome is obstruction of hepatic venous outflow that originates anywhere from the right atrium to the small radicles of the small hepatic vein.
Manifestations renge from no symptoms to fulminant liver failure.
Diagnosis is based on ultrasound.
Treatment includes supportive medical therapy and measures to establish and maintain venous patency,such as thrombolysis,decompression with shunts,and long term anticoagulation.
Etiology and Pathophysiology
Obstruction that originates in the small radicles of the hepatic vein overlaps with veno-occlusive disease.
In the Western world,the most common cause of Budd-Chiari syndrome is a clot at the junction of the hepatic vein and inferior vena cava.
Common cause include thrombotic coagulopathies (eg protein C or S deficiency , antithrombin III deficiency,pregnancy,oral contraceptive use), hematologic diseases (e.g polycyhemia,paroxysmal nocturnal hemoglobinopathy,myeloprolferative disorder), inflammatory bowel disease,connective tissue diseases and trauma.
Other causes are infection (e.g hydatid cyst,ameba) and tumor invasion of hepatic vein (e.g hepatocellular or renal cell carcinoma).
The causes of obstruction are often unknown. In Asia and South Africa the cause is often membranous obstruction (webs) of the inferior vena cava above the liver, likely representing recanalization of a prior thrombus in adults or a developmental defect ( e.g venous stenosis ) in children.
Consequences of venous obstruction include acites,portal hypertension,and hypersplenism.
Symptoms and Signs
Manifestations range from asymptomatic to fulminant liver failure or cirrhosis.
Acute obstruction (classic Budd_Chiari syndrome) causes right upper quadrant pain,nausea and vomiting,mild jaundice,tender hepatomegaly, and ascites.
With complete inferior vena cava obstruction, patients have edema of the abdominal wall and legs plus visibility tortuous superficial abdominal veins from the pelvis to the costal margin.
Fulminant liver failure and encephalopathy occur rarely and sporadically during pregnancy.
A more sebacute course (<6 mo ) manifests as hepatomegaly,coagulopathy,ascites,splenomegaly,variceal bleeding ,and the hepatorenal syndrome.
Most presentations are chronic (> 6 mo) and include fatigue,tortuous superficial abdominal veins,and in some patients,variceal bleeding, ascites,and decompesated cirrhosis.
Diagnosis
Budd-Chiari syndrome is suspected when hepatomegaly,ascites,liver failure.or cirrhosis is present or when abnormal liver function test results coincide with risk factors for thrombosis.
Abdominal Doppler Ultrasound results show the direction of blood flow and the site of obstruction.CT and MRI are useful if ultrasound is not diagnostic.
Angiography is necessary if surgery is planned.
Laboratory test, though not diagnostic,help evaluate liver function.
Prognosis and Treatment
Most patients with complete venous obstruction die of liver failure within 3 years. Those with incomplete obstruction have a variable course.
Treatment includes supportive medical therapy for complications (e.g ascites,liver failure) and decompression.
Thrombolysis may dissolve acute clots and relievehepatic congestion. For caval webs or hepatic venous stenosis,percutaneous transluminal stents maintaisn outflow .
Transjugular intrahepatic stents and many surgical shunts also provide decompression.
Shunts generally are not used if hepatic encephalopathy is present and hepatic synthetic function is impaired,because shunts often worsen liver function.
Also, shunts tend to thrombose,especially with hematologic disorders. Long-term anti coagulation I soften necessary to prevent recurrence. Liver transplantation may be lifesaving in case of fulminant disease or decompensated cirrhosis.
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