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 like nephrotic syndrome, heart failure, and malignancy.
• Amount of fluid accumulation:
  • Grade 1: mild ascites—only detected by ultrasound (US); responsive ascites
  • Grade 2: moderate ascites—moderate symmetric distension of abdomen; 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 and malignancy
• Adults: cirrhosis (81%), cancer (10%), heart failure (3%), tuberculosis (TB) 2%, other (6%)
• 50% of patients with decompensated cirrhosis develop ascites.

Incidence
Approximately 50–60% of cirrhotic patients develop ascites within 10 years (2). The presence of ascites in cirrhotic patients is a poor prognostic indicator with mortality of about 44% in 5 years (1).

Prevalence
10% of patients with cirrhosis have ascites.

Etiology and Pathophysiology

• Portal hypertension versus nonportal hypertension
  • Cannot reliably establish/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
• 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