Etiology

Normal peritoneum

• Portal hypertension (serum-ascites albumin gradient [SAAG] ? 1.1 g/dL)
  • Liver disease
    1. Cirrhosis (most common)
    2. "Mixed ascites" (portal hypertension with secondary process, eg, malignancy, infection)
    3. Alcoholic hepatitis
    4. Fulminant hepatic failure
    5. Massive hepatic metastases
    6. Hepatic fibrosis
    7. Acute fatty liver of pregnancy
  • Hepatic congestion (usually SAAG ? 1.1 g/dL and ascites total protein >2.5 g/dL)
    1. Congestive heart failure, constrictive pericarditis, tricuspid insufficiency
    2. Budd-Chiari syndrome, veno-occlusive disease
  • Portal vein occlusion
• Hypoalbuminemia (SAAG < 1.1 g/dL)
  • Nephrotic syndrome
  • Protein-losing enteropathy
  • Severe malnutrition with anasarca
• Miscellaneous conditions (SAAG < 1.1 g/L)
  • Chylous ascites
  • Pancreatic ascites
  • Bile ascites
  • Nephrogenic ascites
  • Urine ascites
  • Myxedema (SAAG ? 1.1 g/dL)
  • Ovarian disease

Diseased peritoneum (SAAG < 1.1 g/dL except in "mixed ascites" with portal hypertension and secondary process, eg, infection, malignancy)

• Infections
  • Bacterial peritonitis
  • Tuberculous peritonitis
  • Fungal peritonitis
  • HIV-associated peritonitis
• Malignant conditions
  • Peritoneal carcinomatosis
  • Primary mesothelioma
  • Pseudomyxoma peritonei
  • Massive hepatic metastases
  • Hepatocellular carcinoma

• Other conditions
  • Familial Mediterranean fever
  • Vasculitis
  • Granulomatous peritonitis
  • Eosinophilic peritonitis