(See also Overview of Vascular Disorders of the Liver.)
Etiology
Common causes vary by age group (see table Common Causes of Portal Vein Thrombosis).
Common Causes of Portal Vein Thrombosis*
Age Group |
Cause |
Comments |
|
Neonates |
Umbilical stump infection, or omphalitis (spread via the umbilical vein to the portal vein) Congenital portal vein abnormalities (less common) |
Congenital abnormalities of the portal vein usually accompany congenital defects elsewhere. |
|
Older children |
Pylephlebitis |
In acute appendicitis, infection enters the portal system; the vascular infection/inflammation then triggers thrombosis. |
|
Adults |
Surgery (eg, splenectomy) Hypercoagulable states (eg, myeloproliferative disorder, protein C or S deficiency, pregnancy) Cancer (eg, hepatocellular or pancreatic carcinoma, renal cancers or adrenal cancers) Trauma Possibly portal hypertension causing congestion and stasis |
|
|
* The cause is multifactorial in most cases and unknown in about one third of cases. |
||
Symptoms and Signs
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 pre-sinusoidal 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 gastrointestinal bleed.
Diagnosis
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Clinical evaluation and liver tests
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Doppler ultrasonography
Portal vein thrombosis is suspected in patients with the following:
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Manifestations of portal hypertension without cirrhosis
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Mild abnormalities in liver function or enzymes plus risk factors such as neonatal umbilical infection, childhood appendicitis, or a hypercoagulability disorder
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.
Treatment
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; treatment can include octreotide IV (a synthetic analog of somatostatin) and endoscopic banding to control variceal bleeding and nonselective beta-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) has a limited role in the treatment of portal vein thrombosis (see [1]).
Treatment reference
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Valentin N, Korrapati P, Constantino J, et al: The role of transjugular intrahepatic portosystemic shunt in the management of portal vein thrombosis: A systematic review and meta-analysis. Eur J Gastroenterol Hepatol 30(10):1187-1193, 2018.
Key Points
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Causes of and risk factors for portal vein thrombosis include umbilical cord infection (in neonates), appendicitis (in children), and hypercoagulability states (in adults).
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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.
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Confirm the diagnosis using Doppler ultrasonography or, if results are inconclusive, MRI or CT with contrast.
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Treat the cause of portal vein thrombosis and the complications of portal hypertension.
