Budd-Chiari syndrome overview
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# Overview
The Budd-Chiari syndrome is caused by occlusion of the hepatic vein or inferior vena cava. It presents with the classical triad of abdominal pain, ascites, and hepatomegaly. Examples of occlusion include thrombosis of hepatic veins and membranous webs in the inferior vena cava. The syndrome can be fulminant, acute, chronic, or asymptomatic.

# Historical Perspective
Budd-Chiari syndrome (BCS) was first discovered by George Budd in 1845. In 1899, Hans Chiari was the first to describe the histopathology of Budd-Chiari syndrome (BCS).

# Classification
Budd-Chiari syndrome may be classified into several subtypes based on etiology, disease duration, severity and anatomical location of the occlusion. An obstruction below 300m in diameter is not considered as BCS by some authors. Budd-Chiari syndrome may be classified according to etiology into two subtypes: primary and secondary. Budd-Chiari syndrome may be classified according to disease duration and severity into four subtypes: acute, subacute, chronic, fulminant liver failure. Budd-Chiari syndrome may be classified according to the anatomical location of obstruction into three subtypes: type I - truncal type, type II - radicular type, type III - venooclusive type.

# Pathophysiology
Occlusion of at least two hepatic veins leads to Budd-Chiari syndrome. Single hepatic vein occlusion is usually silent. Obstruction in the venous drainage from liver results in venous congestion causing hepatomegaly. Patients develop postsinusoidal portal hypertension. Stasis of blood and congestion cause hypoxic damage to hepatocytes, affecting the liver function.This can result in centrilobular fibrosis, nodular regenerative hyperplasia and ultimately cirrhosis. Hepatocellular necrosis results from increased sinusoidal pressure. Budd-Chiari is commonly associated with atrophy of peripheral regions and enlargement of the caudate lobe because blood is directly shunted through it into the inferior vena cava. Genes associated with increased expression in the pathogenesis of Budd-Chiari syndrome include matrix metalloproteinase 7, superior cervical ganglion 10 (SCG10), proliferating cell nuclear antigen gene, c-MYC oncogene, tumor protein p53 gene, and thrombospondin-1 gene.

# Causes
Budd-Chiari syndrome is associated with a wide range of etiologies. On the basis of underlying cause, Budd-Chiari can be Primary(75%), caused by thrombosis of the hepatic vein, and Secondary (25%), caused by the invasion and/or compression of the hepatic vein by an outside structure like(e.g. a tumor, abscess or cysts). Causes include myeloproliferative disorders, malignancy, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, factor V Leiden mutation, infections and benign liver lesions, oral contraceptives and pregnancy, hypercoagulable states, Behcet's syndrome, and membranous webs.

# Differentiating Budd-Chiari syndrome from Other Diseases
Budd-Chiari syndrome can be differentiated from other causes of hepatic failure like viral hepatitis and liver cirrhosis.

# Epidemiology and Demographics
In 2009-2013, the prevalence of Budd-Chiari syndrome was estimated to be 424 patients cases per 5.29 per million (100,000) individuals in South Korea. Budd-Chiari syndrome is a rare disease. The incidence of Budd-Chiari syndrome was estimated to be about 1 case per million population per year of 100,000 individuals in Sweden. The annual case fatality rate of Budd-Chiari syndrome is approximately 2.8%. Budd-Chiari syndrome commonly presents in the third or fourth decade of life. The median age of diagnosis is 51 years, thus Budd-Chiari syndrome is rare in children. Females are more commonly affected by Budd-Chiari syndrome than males. The female-to-male ratio is approximately 1.8 to 1. Budd-Chiari syndrome in the United States is predominantly seen in women and is commonly associated with hematologic disorders. Congenital membranous forms are the most common cause of Budd-Chiari syndrome worldwide and particularly in Asia.

# Risk Factors
Approximately 80 percent of patients with the Budd-Chiari syndrome have an underlying disorder. Many patients may have more than one risk factor. The same patient may have multiple causes that predispose to the development of Budd-Chiari Syndrome. Associated risk factors include hematologic disorders, coagulopathies, chronic infections, chronic inflammatory diseases, tumors, congenital membranous obstructions.

# Screening
There is insufficient evidence to recommend routine screening for Budd-Chiari syndrome.

# Natural History, Complications, and Prognosis

## Natural History
The symptoms of Budd-Chiari syndrome usually develop in the third or fourth decade of life and start with symptoms such as hepatomegaly, ascites, and abdominal pain. Without treatment, the patient will develop complications like hepatic encephalopathy, variceal hemorrhage, hepatorenal syndrome, portal hypertension, complications secondary to hepatic decompensation, which may eventually lead to intractable ascites with emaciation, gastrointestinal bleeding, and liver failure.

## Complications
Complications that can develop as a result of Budd-Chiari syndrome are portal hypertension, hepatic encephalopathy, variceal hemorrhage, hepatorenal syndrome, hepatic decompensation, bacterial peritonitis, especially the following paracentesis.

## Prognosis
If left untreated, patients with Budd-Chiari syndrome have a high mortality rate. About 90% die within 3 years as the disease may progress to develop intractable ascites with emaciation, gastrointestinal bleeding, and liver failure. Prognosis is generally good with treatment, and the 5-year survival rate of patients with treatment of Budd-Chiari syndrome is approximately 74%. Poor prognostic factors include older age at diagnosis, chronic disease, severe liver failure and associated refractory ascites.

# Diagnosis

## History and Symptoms
The hallmark of Budd-Chiari syndrome is a triad of right upper quadrant abdominal pain, ascites, and hepatomegaly. Symptoms of Budd-Chiari syndrome include fever, abdominal pain, abdominal distension from ascites, lower extremity edema, jaundice, gastrointestinal bleeding from varices, portal hypertensive gastropathy, and hepatic encephalopathy. Patients with subacute or chronic Budd-Chiari syndrome may be asymptomatic.

## Physical Examination
Common physical examination findings of Budd-Chiari syndrome include fever, jaundice, hepatomegaly, ascites, splenomegaly, ankle edema, and venous stasis ulcer.

## Laboratory Findings
Suspect Budd-Chiari syndrome in patients with predisposing conditions such as malignancy or hypercoagulable states. When Budd-Chiari syndrome is suspected, measurements are made of liver enzyme levels, creatinine, urea, electrolytes, and LDH. Liver biopsy for the presence of antiphospholipid antibodies is usually tested for patients with primary BCS. Bone marrow biopsy can be used to diagnose associated myeloproliferative disorders are common in BCS. Laboratory findings consistent with the diagnosis of acute and fulminant BCS include: elevated serum aspartate aminotransferase and serum alanine aminotransferase levels which may be more than five times the upper limit of the normal range and elevated serum alkaline phosphatase and bilirubin levels, decreased serum albumin level. Ascitic fluid examination shows: total protein more than 2.5 g per deciliter and white blood cells are usually less than 500/L. Additional hematological tests are recommended to evaluate for hypercoagulability.

## Electrocardiogram
There are no ECG findings associated with Budd-Chiari syndrome.

## X-Ray
There are no x-ray findings associated with Budd-Chiari syndrome (BCS). However, an x-ray may be helpful in the diagnosis of complications of Budd-Chiari syndrome (BCS) like esophageal varices seen as lobulated posterior mediastinal masses on x-ray. Portal hypertension was seen as silhouetting of the descending aorta and convex contour of the azygos-esophageal recess on x-ray. Most x-ray findings associated with Budd-Chiari syndrome (BCS) have low sensitivity and are nondiagnostic.

## CT
CT scan may be helpful in the diagnosis of Budd-Chiari syndrome. Contrast-enhanced computed tomography (CT) is performed in portal venous phase, this helps to obtain good contrast filling in the portal, mesenteric, and hepatic veins and in inferior vena cava for detection of associated pathology. Findings on CT scan suggestive of Budd-Chiari syndrome include: early enhancement of the caudate lobe and central liver around the inferior vena cava, delayed enhancement of the peripheral liver with accompanying central low density (flip-flop appearance), inhomogeneous mottled liver (nutmeg liver), peripheral zones of the liver may appear hypoattenuating because of reversed portal venous blood flow, inability to identify hepatic veins, in the chronic phase, there is caudate lobe enlargement and atrophy of the peripheral liver in affected areas.

## MRI
MRI may be helpful in the diagnosis of Budd Chiari. Findings on MRI suggestive of BCS include the following hepatic vein thrombosis, spontaneous intrahepatic anastomoses, ascites, thrombosis of the IVC by an enlarged caudate lobe or external compression of the IVC by an enlarged caudate lobe, prominent azygos and hemiazygos veins, hepatomegaly, and enlarged caudate lobe. Homogeneous or Inhomogeneous signal intensity of hepatic parenchyma on T1- and T2-weighted MRI scans.

## Ultrasound
Ultrasound may be helpful in the diagnosis of Budd-Chiari. Ultrasound is the first line imaging method preferred for its high sensitivity and specificity of up to 85%. Color-flow Doppler ultrasonography is used to confirm the diagnosis of Budd-Chiari syndrome.

## Other Imaging Findings

### Nuclear Imaging
Nuclear Imaging may be helpful in the diagnosis of Budd-Chiari syndrome (BCS). Findings on 99m Tc sulfur colloid scanning suggestive of Budd-Chiari syndrome (BCS) include sulfur colloid uptake technetium-99m (99mTc) is increased (ie, hot) in the caudate lobe when compared to the rest of the liver, in which uptake may be normal, reduced, absent, or patchy, colloid may shift to the spleen and bone marrow, wedge-shaped focal peripheral defects are occasionally seen on imaging.

## Other Diagnostic Studies
Liver Biopsy and histology is a useful investigation if liver transplantation is being considered as it helps identify the degree of hepatocellular damage and the degree of fibrosis. Findings on liver biopsy suggestive of Budd Chiari include venous congestion high grade, centrilobular liver cell atrophy, thrombi within the terminal hepatic venules, massive fibrosis in fulminant hepatic failure. Invasive imaging methods are used to identify obstruction of the venous outflow. Angiography of the inferior vena cava and hepatic veins can be used together with interventional therapeutic procedures to restore patency of the vessels.

# Treatment

## Medical Therapy
Medical therapy can be used for short-term symptomatic relief in Budd-Chiari syndrome. However, the use of such medical therapy alone is associated with a high 2-year mortality rate. A low-sodium diet is recommended for patients with Budd-Chiari syndrome. This helps in effective control of ascites. Symptomatic treatment includes diuretics to control ascites, anticoagulants such as heparin and warfarin for hypercoagulable state and antifibrinolytic agents.

## Surgery
Therapeutic paracentesis can be used for symptomatic treatment of ascites. Paracentesis can be associated with complications such as bacterial peritonitis. The benefits of therapeutic paracentesis must be carefully weighed against its risks.The choice of interventional procedures in the treatment of BCS is based on the type of venous occlusion. Aspiration thrombectomy followed by predilatation with a small diameter catheter. This is associated with a decreased risk of pulmonary embolism and allows the introduction of a thrombolytic catheter for administration of a thrombolytic agent. Endovascular treatment is indicated in patients with thrombosed IVC. Recanalization of the occluded IVC results in rapid clinical improvement. Angioplasty is recommended for patients with occluded hepatic vein and patent inferior vena cava. Stenting is preferred if the hepatic vein has a straight course and is of sufficient diameter (7 mm). Transjugular portosystemic shunt (TIPS) is recommended in patients who have developed liver cirrhosis. Transjugular portosystemic shunt (TIPS) decreases porto-systemic gradient hence reducing the risk of variceal bleeding. Liver transplantation is the last rescue treatment when conservative and interventional therapy does not prevent the development of liver cirrhosis and progressive liver failure in chronic BCS. It is generally reserved for patients with fulminant hepatic failure, failure of shunts, or progression of cirrhosis that reduces the life expectancy to 1 year.

## Prevention

### Primary Prevention
Measures for the primary prevention of Budd-Chiari syndrome include effective management of predisposing conditions, chronic anticoagulation in patients with the underlying hypercoagulable disorder, treat patients with an underlying myeloproliferative disorder with aspirin and hydroxyurea rather than anticoagulants such as warfarin.

### Secondary prevention
Secondary prevention strategies following Budd-Chiari syndrome include: anticoagulation should be initiated immediately in patients to prevent propagation of the clot, provided there are no contraindications. Effective management of esophageal varices. Patients with Budd-Chiari syndrome treated with balloon dilatation or stents require follow-up catheterizations and repeat dilatations or stent replacement. All patients should have routine surveillance for hepatocellular carcinoma (HCC).