Pathophysiology: Liver & Ascites

Ascites occurs when there is a disruption in the pressure forces between intravascular and extravascular fluid spaces, which allows extravascular fluid to accumulate in the anterior peritoneal cavity.

The most common causes of ascites include chronic parenchymal liver disease (alcoholic liver disease, cirrhosis due to viral hepatitis C), malignancy, and heart failure.

Classification by mechanism of ascites formation

1. Elevated hydrostatic pressure (portal hypertension)
   1. Cirrhosis
   2. Hepatic congestion:
      • Congestive heart failure
      • Constrictive pericarditis
      • Inferior vena cava syndrome
      • Hepatic vein obstruction (Budd-Chiari syndrome)
   3. Portal vein occlusion
2. Decreased osmotic pressure
   1. Hypoalbuminemia:
      • Nephrotic syndrome
      • Protein-losing enteropathy
      • Malnutrition
   2. Cirrhosis or hepatic insufficiency
3. Fluid production exceeding resorptive capacity (associated with peritoneal disease)
   1. Infections:
   2. Bacterial peritonitis (acute; spontaneous forms)
      • Tuberculosis
      • Fungal
      • Parasitic
   3. Malignancy:
      • Metastatic carcinoma
      • Primary mesothelioma
   4. Granulomatous peritonitis
      • Infections
      • Cancer
      • Iatrogenic:
            starch, barium
      • Vasculitis

For more discussion on pathogenesis of ascites, check the references.

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