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Portal Vein Thrombosis
Portal vein thrombosis causes portal hypertension and consequent GI bleeding from varices, usually in the lower esophagus or stomach. Diagnosis is based on ultrasonography. Treatment involves control of variceal bleeding (usually with endoscopic banding, IV octreotide, or both), prevention of recurrence using β–blockers, and sometimes surgical shunts and thrombolysis for acute thrombosis.
Common causes vary by age group (see Common Causes of Portal Vein Thrombosis*).
Common Causes of Portal Vein Thrombosis*
Acute portal vein thrombosis is commonly asymptomatic unless associated with another event, such as pancreatitis (the cause), or another complication, such as mesenteric venous thrombosis. Most often, clinical features—splenomegaly (especially in children) and variceal hemorrhage—develop over a period of time secondary to portal hypertension. Ascites is uncommon (10%) in postsinusoidal portal hypertension. Ascites may be precipitated when cirrhosis is also present or when serum albumin (and thus oncotic pressure) deceases after high-volume fluid resuscitation for a major GI bleed.
Portal vein thrombosis is suspected in patients with the following:
Doppler ultrasonography is usually diagnostic, showing diminished or absent portal vein flow and sometimes the thrombus. Difficult cases may require MRI or CT with contrast. Angiography may be required to guide shunt surgery.
In acute cases, thrombolysis is sometimes successful, best reserved for recent occlusion, particularly in hypercoagulable states. Anticoagulation does not lyse clots but has some value for long-term prevention in hypercoagulable states despite the risk of variceal bleeding. In neonates and children, treatment is directed at the cause (eg, omphalitis, appendicitis). Otherwise, management is directed at the portal hypertension and its complications (see Portal Hypertension); treatment can include octreotide IV (a synthetic analog of somatostatin) and endoscopic banding to control variceal bleeding and nonselective β-blockers to prevent rebleeding. These therapies have decreased the use of surgical shunts (eg, mesocaval, splenorenal), which can become occluded and have an operative mortality rate of 5 to 50%. Transjugular intrahepatic portosytemic shunting (TIPS) is not recommended. TIPS requires monitoring (including frequent angiography) to assess patency, may become blocked, and may not adequately decompress the liver.
Causes of and risk factors for portal vein thrombosis include umbilical cord infection (in neonates), appendicitis (in children), and hypercoagulability states (in adults).
Suspect portal vein thrombosis if patients have manifestations of portal hypertension in the absence of cirrhosis or if they have mild, nonspecific liver abnormalities plus risk factors.
Confirm the diagnosis using Doppler ultrasonography or, if results are inconclusive, MRI or CT with contrast.
Treat the cause of portal vein thrombosis and the complications of portal hypertension
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