153. Diseases of hepatic vessels (hepatic vein thrombosis, portal hypertension) - etiology, pathogenesis, clinical manifestations.

Diseases of hepatic vessels (hepatic vein thrombosis, portal hypertension) – etiology, pathogenesis, and clinical manifestations.

Hepatic vein thrombosis (Budd-Chiari syndrome)

Etiology

• Hypercoagulable states:
• Polycythemia vera.
• Antiphospholipid syndrome.
• Factor V Leiden mutation.
• Oral contraceptives, pregnancy.
• Malignancy (especially hepatocellular carcinoma).
• Infections, trauma.

Pathogenesis

1. Thrombosis or obstruction of hepatic veins (one or more major veins).
2. Impaired hepatic venous outflow → increased sinusoidal pressure.
3. Congestion and centrilobular (zone 3) hepatocyte necrosis.
4. Progressive liver dysfunction → fibrosis → possible cirrhosis.

Clinical manifestations

• Triad:
• Hepatomegaly (painful, tender).
• Ascites.
• Abdominal pain (right upper quadrant).
• Jaundice (in severe cases).
• Signs of liver failure in advanced stages.
• Rapid weight gain due to fluid accumulation.

Portal hypertension

Increased pressure in the portal venous system, usually defined as portal vein pressure >12 mmHg (normal ~5–10 mmHg).

Etiology

Pre-hepatic

• Portal vein thrombosis.
• Splenic vein thrombosis.

Intrahepatic (most common)

• Cirrhosis (major cause).
• Schistosomiasis.
• Congenital hepatic fibrosis.

Post-hepatic

• Budd-Chiari syndrome.
• Constrictive pericarditis.
• Right heart failure.

Pathogenesis

1. Increased resistance to portal blood flow (fibrosis, thrombosis, external compression).
2. Development of portosystemic collateral circulation:

• Esophageal and gastric varices.
• Hemorrhoids (rectal varices).
• Caput medusae (dilated periumbilical veins).

3. Splenomegaly due to congestion.
4. Reduced hepatic perfusion → hepatocyte dysfunction.

Clinical manifestations

Consequences of portal hypertension

• Splenomegaly → hypersplenism → cytopenias (anemia, thrombocytopenia, leukopenia).
• Ascites → accumulation of fluid in peritoneal cavity.
• Portosystemic shunts:
• Esophageal varices → risk of life-threatening bleeding.
• Hemorrhoids.
• Caput medusae.
• Hepatic encephalopathy → neuropsychiatric symptoms due to ammonia and toxin accumulation.
• Jaundice (secondary to liver dysfunction).