Oesophageal varices: portosystemic collaterals and why they bleed
- Lesion
When blood cannot pass easily through the liver, it detours through veins in the lower oesophagus, which swell and can burst.
What it is
Portal hypertension forces portal blood into collateral channels wherever the portal and systemic veins meet. At the gastro-oesophageal junction, the left gastric (coronary) vein connects with oesophageal veins that drain to the azygos system; these thin submucosal veins dilate into varices. Most cases are due to cirrhosis, but presinusoidal (portal vein thrombosis, schistosomiasis) and postsinusoidal (Budd–Chiari) obstruction also cause them.
Structure
- Gross: tortuous dilated veins in the submucosa of the distal oesophagus and proximal stomach; they collapse after death, so they are easy to miss at autopsy.
- Micro: thin-walled dilated veins in the submucosa and lamina propria with thinned overlying epithelium.
- After rupture: haemorrhage into the lumen or wall, mucosal ulceration and necrosis; later thrombosis, inflammation and changes from earlier band ligation or sclerotherapy.
Step by step
- Resistance to portal flow rises (most often from cirrhosis).
- Portal pressure rises and blood is diverted into portosystemic collaterals.
- The left gastric to oesophageal (azygos) connection carries much of the flow.
- Submucosal veins dilate and their walls and covering mucosa thin.
- Erosion of the mucosa or a further pressure rise ruptures the varix.
Clinical notes
- Variceal bleeding is an emergency managed with splanchnic vasoconstrictors, endoscopic band ligation, balloon tamponade or a portosystemic shunt.
- Bleeding can tip a patient with cirrhosis into hepatic encephalopathy, because blood in the gut is a protein load.
Test yourself
Think of the answer, then tap the question to see it.
Which venous connection forms oesophageal varices?
The left gastric (coronary) vein of the portal system joining oesophageal veins that drain into the azygos system.
Why can varices be missed at autopsy?
The veins collapse when blood pressure is lost, so they flatten unless specially prepared.
Which non-cirrhotic cause of varices is common in endemic regions?
Schistosomiasis, which causes presinusoidal portal hypertension through periportal fibrosis.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Bleeding esophageal varices: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Upper Gastrointestinal Bleeding (StatPearls (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.