Budd–Chiari syndrome is the clinical picture caused by occlusion of the hepatic veins. It presents with the classical triad of abdominal pain, ascites and hepatomegaly. Examples of occlusion include thrombosis of hepatic veins. The syndrome can be fulminant, acute, chronic, or asymptomatic. It occurs in 1 out of a million individuals and is more common in females. Some 10-20% also have obstruction of the portal vein.
The acute syndrome presents with rapidly progressive: severe upper abdominal pain, jaundice, hepatomegaly (enlarged liver), ascites, elevated liver enzymes, and eventually encephalopathy. The fulminant syndrome presents early with encephalopathy and ascites. Severe hepatic necrosis and lactic acidosis may be present as well. Caudate lobe hypertrophy is often present.
However 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.
Causes
The cause cannot be found in about half of the patients. However for those cases with a discernable cause:
- 75% have thrombosis of the hepatic vein
- 25% have compression of the hepatic vein by an outside structure (e.g. a tumor)
Hepatic vein thrombosis is associated with the following in decreasing order of frequency.
- Polycythemia vera
- Pregnancy
- post partum state
- use of oral contraceptive
- paroxysmal nocturnal hemoglobinuria
- Hepatocellular carcinoma.
Often, the patient is known to have a tendency towards thrombosis, although Budd–Chiari syndrome can also be the first symptom of such a tendency. Examples of genetic tendencies include Protein C deficiency, Protein S deficiency, the Factor V Leiden mutation, and Prothrombin Mutation G20210A.
An important non-genetic risk factor is the use of estrogen-containing forms of hormonal contraception. Other risk factors include
- antiphospholipid syndrome
- aspergillosis
- Behçet's disease
- Dacarbazine
- Pregnancy
- trauma.
Many patients have Budd–Chiari syndrome as a complication of haematological disease:
- Polycythemia vera
- Paroxysmal nocturnal hemoglobinuria
- thrombophilia
A related condition is veno-occlusive disease, which occurs in recipients of bone marrow transplants as a complication of their medication. Although its mechanism is similar, it is not considered a form of Budd–Chiari syndrome.
Interestingly toxicologic causes of veno-occlusive disease include traditional herbal remedies such as plant & herbal sources of pyrrolizidine alkaloids:
- Borage
- Boneset
- Coltsfoot
- T'u-san-chi
- Comfrey
- Heliotrope (sunflower seeds)
- Gordolobo
- Germander
- Chaparral.
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