Portal Vein Thrombosis

By Nicholas T. Orfanidis, MD, Clinical Assistant Professor, Thomas Jefferson University Hospital

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Vascular Disorders of the Liver
Overview of Vascular Disorders of the Liver
Budd-Chiari Syndrome
Congestive Hepatopathy
Hepatic Artery Aneurysms
Hepatic Artery Occlusion
Ischemic Cholangiopathy
Ischemic Hepatitis
Peliosis Hepatis
Portal Vein Thrombosis
Veno-Occlusive Disease

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 beta-blockers, and sometimes surgical shunts and thrombolysis for acute thrombosis.

Etiology

Common causes vary by age group (see 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 or adrenal cancers) Cirrhosis 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 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.

Diagnosis

Clinical evaluation and liver function tests
Doppler ultrasonography

Portal vein thrombosis is suspected in patients with the following:

Manifestations of portal hypertension without cirrhosis
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

For some acute cases, thrombolysis
Long-term anticoagulation
Management of portal hypertension and its complications

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) is not recommended. TIPS requires monitoring (including frequent angiography) to assess patency, may become blocked, and may not adequately decompress the liver.

Key Points

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