Sinistral Portal Hypertension

Sinistral (left sided or segmental) portal hypertension is raised pressure in the splenic and short gastric veins from isolated splenic vein occlusion, with normal liver function and normal portal vein pressure. It produces gastric varices and, less often, oesophageal varices.

Pancreatitis causes about 60% of cases, followed by pancreatic cancer, neuroendocrine tumour and cyst, and thrombophilia. Splenic vein thrombosis occurs in 5% to 45% of chronic pancreatitis, and gastric varices follow in up to 50% of those with occlusion. Bleeding risk is lower than in cirrhosis.

Pathophysiology.

Splenic venous blood drains through the short gastric and gastroepiploic veins into the gastric fundus and the coronary vein, forming isolated fundal varices.

Often silent, found at imaging or endoscopy. Bleeding presents with haematemesis or melaena, with an enlarged spleen and abdominal pain from the underlying pancreatic disease. Ascites is absent, and liver function is normal.

Red flags.

• Haematemesis or melaena.
• Haemodynamic instability.
• Pancreatic mass.

Upper endoscopy shows isolated gastric fundal varices with normal oesophagus and non-cirrhotic liver. CT with portal venous phase or Doppler ultrasound shows splenic vein occlusion with collaterals, splenomegaly and pancreatic disease. Check liver tests and platelets; exclude cirrhosis by elastography and exclude cancer by imaging and endoscopic ultrasound.

Differential diagnosis.

• Cirrhotic portal hypertension.
• Extrahepatic portal vein obstruction.
• Splenic arteriovenous fistula.
• Gastric cancer.
• Gastric antral vascular ectasia.

Asymptomatic varices do not need treatment. For bleeding, stabilise and use endoscopic cyanoacrylate injection (0.5 to 1 mL aliquots mixed with lipiodol; maximum 2 mL at each site). Splenectomy cures sinistral portal hypertension and is advised after bleeding, and splenic artery embolisation is an alternative for patients unfit for surgery. Treat the underlying pancreatic disease.

• Pneumococcal conjugate vaccine: 0.5 mL IM once, at least 2 weeks before splenectomy; follow with the polysaccharide vaccine 8 weeks later; monitor injection site; no renal adjustment.
• Meningococcal ACWY and B vaccines: 0.5 mL IM, two doses of the B vaccine 1 month apart, at least 2 weeks before splenectomy; monitor for fever; no renal adjustment.
• Phenoxymethylpenicillin after splenectomy: 500 mg orally twice daily for at least 2 years; maximum 1 g daily; monitor for rash; reduce to 250 mg twice daily when creatinine clearance is under 10 mL/min.
• Pantoprazole after cyanoacrylate injection: 40 mg orally once daily for 4 weeks; maximum 80 mg daily; monitor magnesium; reduce to 20 mg daily in severe hepatic impairment.

Beta blockers are not useful, because portal vein pressure is normal.

Monitoring. Repeat endoscopy at 4 to 8 weeks after injection; full blood count after splenectomy.

Referral and escalation. Pancreatic and hepatobiliary surgery, interventional radiology and endoscopy.