(See also Overview of Vascular Disorders of the Liver.)
Etiology of Portal Vein Thrombosis
Common causes vary by age group (see table Common Causes of Portal Vein Thrombosis ). The cause is multifactorial in most cases and unknown in about one-third of cases (1).
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 deficiency or protein S deficiency, pregnancy) Cancer (eg, hepatocellular or pancreatic carcinoma, renal cancers or adrenal cancers) Trauma Possibly portal hypertension causing congestion and stasis |
Etiology reference
1. Northup PG, Garcia-Pagan JC, Garcia-Tsao G, et al: Vascular Liver Disorders, Portal Vein Thrombosis, and Procedural Bleeding in Patients With Liver Disease: 2020 Practice Guidance by the American Association for the Study of Liver Diseases. Hepatology 73(1):366-413, 2021. doi: 10.1002/hep.31646.
Symptoms and Signs 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 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 of Portal Vein Thrombosis
Clinical evaluation and liver 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.
In patients with cirrhosis, venous obstruction due to hepatocellular carcinoma should be excluded with contrast‐enhanced imaging studies. In patients without cirrhosis who have thrombosis of the portal venous system without a clear cause, myeloproliferative disorders or other thrombophilic conditions should be excluded; consultation with a hematologist should be considered (1).
Diagnosis reference
1. Northup PG, Garcia-Pagan JC, Garcia-Tsao G, et al: Vascular Liver Disorders, Portal Vein Thrombosis, and Procedural Bleeding in Patients With Liver Disease: 2020 Practice Guidance by the American Association for the Study of Liver Diseases. Hepatology 73(1):366-413, 2021. doi: 10.1002/hep.31646
Treatment of Portal Vein Thrombosis
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 (1). 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 hypertensionportal vein thrombosis (2).
Treatment references
1. Northup PG, Garcia-Pagan JC, Garcia-Tsao G, et al: Vascular Liver Disorders, Portal Vein Thrombosis, and Procedural Bleeding in Patients With Liver Disease: 2020 Practice Guidance by the American Association for the Study of Liver Diseases. Hepatology 73(1):366-413, 2021. doi: 10.1002/hep.31646
2. 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. doi: 10.1097/MEG.0000000000001219
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.
