Description

Accumulation of fluid in the peritoneal cavity; may occur in conditions that cause generalized edema

Epidemiology

• Children: Nephrotic syndrome and malignancy most common
• Adults: Cirrhosis, heart failure, nephrotic syndrome, peritonitis most common
• ~85% of all cases of ascites are caused by liver disease and cirrhosis.

Incidence
~50–60% of patients with cirrhosis will develop ascites within 10 years.

Prevalence
10% of patients with liver cirrhosis have ascites.

Pathophysiology

• May develop as a consequence of sustained portal hypertension (portal pressure >12 mm Hg). Interactions of biochemical mediators (e.g., nitric oxide) lead to decreased systemic vascular resistance, splanchnic arterial vasodilation, reduced effective circulating arterial blood volume, and reduced renal perfusion.
• Renal hypoperfusion contributes to activation of systemic vasoconstrictors and antinatriuretic mechanisms, stimulating the sympathetic nervous system and renin-angiotensin-aldosterone system, ultimately culminating in sodium and water retention causing development of ascites and edema.

Etiology

• Acute liver failure
• Hepatitis (alcoholic, viral, autoimmune, drugs)
• Peritoneal infection and inflammation:
  • Bacterial infection (foreign body, fistula), tuberculosis, fungal disease, parasitic infection
  • Perforated viscus
  • Granulomatous peritonitis (e.g., sarcoidosis)
• Metabolic diseases:
  • Cirrhosis or prehepatic and posthepatic portal hypertension
  • Nephrotic syndrome
  • Myxedema
  • Protein malnutrition (hypoalbuminemia <2 g/dL)
• Cardiac congestion:
  • Congestive heart failure (CHF), constrictive pericarditis
• Trauma:
  • Pancreatic or biliary fistula
  • Lymphatic tear (chylous ascites), hemoperitoneum (trauma, ectopic pregnancy, tumor)
• Malignancy:
  • Peritoneal seeding: Ovarian, colon, pancreas, others
  • Primary peritoneal carcinoma, leukemia, or lymphoma
• Mixed (>1 of the above causes, e.g., cirrhosis and cancer)