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[Conditions](https://durgical.com/en/conditions/) · [Gastroenterology and hepatology](https://durgical.com/en/conditions/)

# Portal vein thrombosis

A blood clot in the portal vein, which carries blood from the gut to the liver. It can cause pain or bowel damage early, and later varices and bleeding.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Portal vein](https://durgical.com/en/anatomy/hepatic-portal-vein/)
- [Splenic vein](https://durgical.com/en/anatomy/splenic-vein/)
- [Liver](https://durgical.com/en/anatomy/liver/)
- [Mesenteric veins](https://durgical.com/en/anatomy/superior-mesenteric-vein/)
- [Spleen](https://durgical.com/en/anatomy/spleen/)
- [Hepatic veins](https://durgical.com/en/anatomy/hepatic-veins/)
- [Jejunum](https://durgical.com/en/anatomy/jejunum/)
- [Stomach](https://durgical.com/en/anatomy/stomach/)
- [Superior mesenteric artery](https://durgical.com/en/anatomy/superior-mesenteric-artery/)

## Why it happens

- [Thrombosis and Virchow's triad](https://durgical.com/en/general-pathology/thrombosis-and-virchow-s-triad/)
- [Hypercoagulable states: inherited and acquired](https://durgical.com/en/general-pathology/hypercoagulable-states-inherited-and-acquired/)
- [Splanchnic and portal circulation](https://durgical.com/en/physiology/splanchnic-and-portal-circulation/)
- [The coagulation cascade](https://durgical.com/en/physiology/the-coagulation-cascade/)

## What it is

Partial or complete blockage of the portal vein by a thrombus, sometimes extending into the splenic or [superior mesenteric vein](https://durgical.com/en/anatomy/superior-mesenteric-vein/). Acute thrombosis can cause abdominal pain and intestinal ischaemia; chronic thrombosis leads to portal hypertension with varices and splenomegaly, while liver function is usually preserved (unless cirrhosis is present).

## Who gets it

Uncommon in the general population but frequent in cirrhosis, where it affects a substantial minority of patients, especially with advanced disease or hepatocellular carcinoma. In children it is a leading cause of non-cirrhotic portal hypertension and variceal bleeding, often related to neonatal umbilical catheterisation or omphalitis.

## Causes

- Cirrhosis with slow portal flow
- Cancer: hepatocellular carcinoma invading the vein, pancreatic cancer
- Inherited or acquired prothrombotic states: myeloproliferative neoplasms (JAK2 mutation), factor V Leiden, prothrombin mutation, antiphospholipid syndrome, paroxysmal nocturnal haemoglobinuria, oral contraceptives, pregnancy
- Local inflammation or infection: pancreatitis, appendicitis or diverticulitis with pylephlebitis, inflammatory bowel disease
- Neonates: omphalitis and umbilical vein catheterisation
- Surgery or trauma: splenectomy, abdominal surgery
- Unknown cause in about a third of cases

## Risk factors

- Advanced cirrhosis
- Hepatocellular carcinoma
- Myeloproliferative neoplasms
- Inherited thrombophilia
- Recent abdominal surgery or splenectomy
- Intra-abdominal infection or pancreatitis
- Umbilical catheterisation in the newborn

## Pathophysiology

Virchow's triad applies: slow flow (cirrhosis), endothelial injury (inflammation, surgery) and hypercoagulability. Blocked portal inflow raises pressure in the splanchnic veins. In the acute phase, extension into the mesenteric veins can cause venous intestinal ischaemia and infarction. Over weeks, collateral veins form around the blocked vein (portal cavernoma), and portosystemic collaterals open, producing oesophageal and gastric varices and splenomegaly. The liver keeps receiving arterial blood, so liver function is usually preserved in non-cirrhotic patients.

## Classification

- Acute (recent) versus chronic (with cavernous transformation)
- Cirrhotic versus non-cirrhotic
- Malignant (tumour thrombus) versus bland thrombus
- By extent: partial or occlusive; limited to the portal vein or extending to the splenic or mesenteric veins

## Symptoms and signs

- Often asymptomatic, found on imaging
- Acute: abdominal pain, fever (if septic pylephlebitis), nausea, diarrhoea
- Chronic: haematemesis or melaena from variceal bleeding
- Splenomegaly, especially in children
- Ascites is uncommon unless cirrhosis is present

## Red flags

- Severe abdominal pain out of proportion to examination, bloody diarrhoea or peritonitis (mesenteric venous infarction)
- Vomiting blood or black stools (variceal bleeding)
- High fever with rigors (septic pylephlebitis)
- Sudden worsening of liver function in a patient with cirrhosis

## Diagnosis

**Clinical**
Suspected in acute abdominal pain with prothrombotic risk, in variceal bleeding with normal [liver](https://durgical.com/en/anatomy/liver/) function, in a child with splenomegaly and varices, or in a patient with cirrhosis who decompensates.

**Tests**
Liver tests are usually normal or mildly abnormal in non-cirrhotic patients; blood count may show hypersplenism (low platelets). Look for the cause: thrombophilia screen, JAK2 mutation, paroxysmal nocturnal haemoglobinuria testing, antiphospholipid antibodies; alpha-fetoprotein in cirrhosis. Upper endoscopy screens for varices.

**Imaging**
Doppler ultrasound is the first-line test, showing absent flow or echogenic material in the vein. Contrast CT or MRI confirms the extent, assesses the bowel for ischaemia and distinguishes tumour thrombus (enhances) from bland thrombus; cavernous transformation appears as a network of collateral vessels.

## Differential diagnosis

- Budd-Chiari syndrome (hepatic vein outflow obstruction)
- Cirrhosis with portal hypertension without thrombosis
- Hepatocellular carcinoma with tumour thrombus
- Acute mesenteric arterial ischaemia
- Acute pancreatitis

## Goal of treatment

Recanalise the vein or prevent clot extension, prevent intestinal infarction, treat the underlying cause and prevent or control variceal bleeding.

## Treatment

**Medical**
Anticoagulation (heparin, then oral anticoagulants) for acute thrombosis and for most cirrhotic patients awaiting transplant; long-term when a permanent prothrombotic cause is found. Variceal screening and treatment come first in patients at risk of bleeding.

**Medical**
Antibiotics for septic pylephlebitis; treatment of the underlying cause (myeloproliferative neoplasm, cancer).

**Procedure**
Endoscopic band ligation and non-selective beta-blockers to prevent or treat variceal bleeding; vasoactive drugs (octreotide) during acute bleeding. TIPS or local thrombolysis in selected cases.

**Surgical**
Bowel resection if mesenteric infarction occurs; mesenteric-to-left [portal vein](https://durgical.com/en/anatomy/hepatic-portal-vein/) bypass (Rex shunt) in selected children.

**Follow-up**
Monitor for bleeding while on anticoagulation, serial imaging for recanalisation, haemoglobin, signs of gut ischaemia and endoscopic surveillance of varices.

## Complications

- Mesenteric venous ischaemia and bowel infarction
- Variceal bleeding (oesophageal and gastric)
- Hypersplenism with low platelets
- Portal biliopathy ([bile duct](https://durgical.com/en/anatomy/bile-duct/) compression by collaterals)
- Liver abscess with septic thrombosis
- Worse outcomes and complications at liver transplantation

## Prognosis

Non-cirrhotic chronic thrombosis has a good prognosis if variceal bleeding is controlled; mortality is mainly from the underlying disease or bowel infarction. Early anticoagulation recanalises a good proportion of acute thromboses. In cirrhosis, outcome is determined largely by liver disease severity.

## Prevention

- Thromboprophylaxis in high-risk hospitalised patients and after splenectomy when indicated
- Prompt treatment of intra-abdominal infections
- Aseptic care of umbilical catheters in neonates

## Test yourself

Think of the answer, then tap the question to see it.

## What is the first-line imaging test for portal vein thrombosis?

Doppler ultrasound.

## What is a portal cavernoma?

A network of collateral veins that forms around a chronically blocked portal vein (cavernous transformation).

## A child presents with haematemesis, splenomegaly and normal liver function. A history of what neonatal procedure is relevant?

Umbilical vein catheterisation or omphalitis leading to portal vein thrombosis.

## Which haematological disease should be screened for in unexplained splanchnic vein thrombosis?

Myeloproliferative neoplasms (JAK2 mutation), and also paroxysmal nocturnal haemoglobinuria.

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## Related conditions

- [Portal hypertension](https://durgical.com/en/conditions/portal-hypertension/)
- [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/)
- [Hepatocellular carcinoma](https://durgical.com/en/conditions/hepatocellular-carcinoma/)
- [Budd-Chiari syndrome](https://durgical.com/en/conditions/budd-chiari-syndrome/)
- [Polycythaemia vera](https://durgical.com/en/conditions/polycythaemia-vera/)
- [Inherited thrombophilia](https://durgical.com/en/conditions/inherited-thrombophilia/)
- [Antiphospholipid syndrome](https://durgical.com/en/conditions/antiphospholipid-syndrome/)
- [Acute appendicitis](https://durgical.com/en/conditions/acute-appendicitis/)
- [Acute pancreatitis](https://durgical.com/en/conditions/acute-pancreatitis/)
- [Acute mesenteric ischaemia](https://durgical.com/en/conditions/acute-mesenteric-ischaemia/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Portal Vein Thrombosis - Hepatology - MSD Manual Professional Edition](https://www.msdmanuals.com/professional/hepatic-and-biliary-disorders/vascular-disorders-of-the-liver/portal-vein-thrombosis) (MSD Manual Professional Edition, 2024).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/portal-vein-thrombosis/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/portal-vein-thrombosis/