Description

Ascites is the pathologic accumulation of fluid in the peritoneal cavity and the most common complication of cirrhosis (1). It may occur in conditions that cause generalized edema (e.g., nephrotic syndrome, heart failure, malignancy)

• Amount of fluid accumulation:
  • Grade 1: mild ascites—only detected by ultrasound; responsive ascites
  • Grade 2: moderate ascites—moderate symmetric distension of abdomen visible on exam; recurrent ascites
  • Grade 3: large or gross ascites—marked distension of the abdomen; refractory ascites (RA)
    • Ascitic fluid that recurs after paracentesis or cannot be prevented by treatment
• Men generally have no fluid in peritoneal cavity; women may have up to 20 mL depending on menstrual phase.

Epidemiology

• Children: most commonly associated with nephrotic syndrome, malignancy, portal hypertension and congenital heart disease with right-sided heart failure
• Adults: cirrhosis (81%), cancer (10%), heart failure (3%), tuberculosis (TB) 2%, other (6%)
• 50% of patients with decompensated cirrhosis develop ascites.

Etiology and Pathophysiology

• Portal hypertension versus nonportal hypertension
  • Cannot confirm etiology without paracentesis
  • Serum-ascites albumin gradient (SAAG): (serum albumin level: ascites albumin level) helps to differentiate
• High portal pressure (SAAG ≥1.1 g/dL)—reflects portal hypertension
  • Cirrhosis, hepatitis (alcoholic, viral, autoimmune, medications), acute liver failure, liver malignancy (primary or metastatic), heart failure or constrictive pericarditis, Budd-Chiari syndrome, and portal vein thrombosis
• Normal portal pressure (SAAG <1.1 g/dL)—excludes portal hypertension
  • Peritoneal carcinomatosis, TB, severe hypoalbuminemia (nephrotic syndrome; severe enteropathy with protein loss), Meigs syndrome (ovarian cancer), lymphatic leak (chylous ascites), pancreatitis, inflammatory (vasculitis, lupus serositis, sarcoidosis), other infections (parasitic, fungal), hemoperitoneum (trauma or ectopic pregnancy)
• Pathogenesis of ascites in the setting of portal hypertension (cirrhotic ascites): backward transmission of increased pressure to the visceral capillary bed with subsequent dilation and shift of fluid to the peritoneal cavity.
  • This decreases intravascular volume and leads to hypotension. Systemic hypovolemia triggers renin-angiotensin-aldosterone system.

Risk Factors

• Cirrhosis—hepatitis B and C; alcohol abuse
• Metabolic dysfunction associated steatotic liver disease (MASLD)
• Congestive heart failure (CHF); advanced kidney disease; malignancy
• TB

General Prevention

Lifestyle—appropriate diet; physical activity; safe sexual practices; avoid alcohol misuse and hepatotoxic medications.

Commonly Associated Conditions

Nephrotic syndrome, liver cancer, heart failure