Oesophagus, umbilicus, rectum and retroperitoneum
Mnemonic
Four sites where portal and systemic venous systems meet, each with its clinical sign:
| Site | Portal vein | Systemic vein | Sign |
|---|---|---|---|
| Lower oesophagus | Left gastric | Azygos | Oesophageal varices |
| Umbilicus | Paraumbilical | Epigastric | Caput medusae |
| Anorectal | Superior rectal | Middle and inferior rectal | Rectal varices |
| Retroperitoneal | Colic | Renal, lumbar | Retroperitoneal varices |
“Gut, butt, caput” covers the three that are visible or endoscopically obvious.
Rectal varices are not haemorrhoids: haemorrhoids arise from the normal anal cushions and are no commoner in portal hypertension, whereas rectal varices lie higher and are a direct consequence of it.
The paraumbilical veins run in the falciform ligament to the umbilicus, which is why recanalisation there produces the caput medusae with flow away from the umbilicus.
Expansion
| Site | Portal vein | Systemic vein |
|---|---|---|
| Lower oesophagus | Left gastric | Oesophageal (to azygos) |
| Umbilicus | Paraumbilical | Superficial epigastric |
| Rectum | Superior rectal | Middle and inferior rectal |
| Retroperitoneum | Colic veins | Retroperitoneal (of Retzius) |
| Bare area of liver | Hepatic portal branches | Phrenic veins |
Clinically:
- Oesophageal varices - the most dangerous, because they bleed catastrophically
- Caput medusae - dilated veins radiating from the umbilicus
- Anorectal varices - distinct from ordinary haemorrhoids, which are not caused by portal hypertension
The direction of flow is the giveaway on examination: in caput medusae, blood flows away from the umbilicus, whereas in inferior vena cava obstruction the dilated flank veins carry blood upwards towards the thorax.