Portal hypertension

Portal hypertension is defined as portal venous pressure greater than 12 mmHg.

Pathology

Causes can be split in their relation to the hepatic sinusoids:

• pre-sinusoidal
  • portal vein thrombosis
  • extrinsic compression of portal vein
  • Schistosomiasis (S. mansoni or S. japonicum)
• sinusoidal
  • cirrhosis
• post-sinusoidal
  • Budd-Chiari syndrome
  • hepatic veno-occlusive disease
  • right heart failure or biventricular cardiac failure

Subtypes

• sinistral portal hypertension ⁵

Radiographic features

Ultrasound

• dilated portal vein (>13mm): non-specific
• biphasic or reverse flow in portal vein (late stage): pathognomonic
• recanalisation of paraumbilical vein: pathognomonic
• portal-systemic collateral pathways (collateral vessels/varices)
• splenomegaly
• ascites
• cause of portal hypertension often identified, most commonly liver cirrhosis

CT and MRI

• dilated portal vein +/- mesenteric veins
• contrast enhancement of paraumbilical vein: pathognomonic
• collateral vessels/varices: these are many and can include ⁴
  • ^​coronary venous collaterals: considered one of the commonest ⁴
  • oesophageal collaterals
  • paraumbilical collaterals
  • abdominal wall collaterals
  • perisplenic collaterals
  • retrogastric collaterals
  • paraoesophageal collaterals
  • omental collaterals
  • retroperitoneal colleterals
  • mesenteric colleterals
  • spleno-renal collaterals
  • gastro-renal collaterals
• splenomegaly
• ascites
• cause of portal hypertension often identified, most commonly liver cirrhosis

Treatment and prognosis

• dietary restriction
• medication: propranolol, diuretics
• interventional procedures
  • transjugular intrahepatic portosystemic shunt (TIPS)
  • surgical portosystemic shunt
  • balloon dilatation of hepatic vein (in case of thrombosis/web in hepatic vein)
  • transhepatic clot thrombolysis (in portal vein thrombosis)
  • splenic artery embolisation ³
  • liver transplantation
• treatment of complications

Complications

• ascites
• variceal bleeding (30-50% mortality with each bleed)
• portal hypertensive gastropathy/enteropathy/colopathy
• hepatic encephalopathy
• hepatorenal syndrome
• congestive splenomegaly and hypersplenism

Differential diagnosis

Dilatation of splenic veins at the splenic hilum without splenomegaly may occur in situations such as state of increased perfusion of splenic tissue associated with an immune response ⁶.