What is the initial approach to managing abdominal swelling and ascites?

Initial Approach to Abdominal Swelling and Ascites

All patients presenting with new-onset ascites require immediate diagnostic paracentesis with ascitic fluid analysis as the essential first step, combined with targeted history, physical examination, abdominal ultrasound, and laboratory assessment of liver and renal function. 1

Diagnostic Paracentesis: The Critical First Step

Perform diagnostic paracentesis immediately in all patients with new-onset grade 2 or 3 ascites, all hospitalized patients with worsening ascites, or any complication of cirrhosis. 2, 1 This is the single most important diagnostic and potentially life-saving intervention. 3

Key Point on Safety

• Do not withhold paracentesis due to coagulopathy or thrombocytopathy—serious complications occur in less than 1 in 1,000 procedures. 1
• The procedure can be performed safely at the bedside without routine correction of INR or platelet count. 1

Essential Ascitic Fluid Analysis

Send ascitic fluid for the following mandatory tests:

• Neutrophil count: >250 cells/µL indicates spontaneous bacterial peritonitis (SBP) requiring immediate empiric antibiotics. 1, 3 This must be ruled out at every hospital admission as it carries high mortality risk. 2

• Total protein and albumin: Required to calculate the serum-ascites albumin gradient (SAAG). 1, 3

• Simultaneous serum albumin: Draw at the same time as paracentesis to calculate SAAG. 1

SAAG Calculation: The Key Diagnostic Test

Calculate SAAG by subtracting ascitic fluid albumin from serum albumin. 1, 3

• SAAG ≥1.1 g/dL (or 11 g/L): Indicates portal hypertension with 97% accuracy. 1, 3 This includes cirrhosis (most common), cardiac ascites, and Budd-Chiari syndrome.

• SAAG <1.1 g/dL: Suggests non-portal hypertensive causes such as peritoneal carcinomatosis, tuberculous peritonitis, or nephrotic syndrome. 1

Physical Examination Findings

• Shifting dullness test: The primary physical examination maneuver, but requires at least 1,500 mL of fluid to be detectable. 1 If no flank dullness is present, the patient has less than 10% chance of having ascites. 1

• Fluid wave: Less sensitive than shifting dullness but more specific when present. 4

• Physical examination is particularly unreliable in obese patients, requiring ultrasound confirmation. 1

Laboratory Assessment

Order the following blood tests simultaneously with paracentesis:

• Liver function tests: AST, ALT, bilirubin, alkaline phosphatase to assess hepatic synthetic function. 1

• Renal function tests: Creatinine and BUN to evaluate for hepatorenal syndrome or other renal complications. 1

• Prothrombin time/INR and complete blood count: To assess coagulopathy and thrombocytopenia. 1

• Serum albumin: Essential for SAAG calculation. 1

Differential Diagnosis by Prevalence

Understanding the epidemiology guides your diagnostic approach:

• Cirrhosis: Accounts for 75-85% of all ascites cases in Western countries. 1, 3 This is overwhelmingly the most common cause.

• Malignancy: The second most common cause, accounting for approximately 10% of cases. 1 Consider peritoneal carcinomatosis, especially with low SAAG.

• Cardiac failure: Accounts for approximately 3-6% of cases. 2 Look for elevated jugular venous pressure and peripheral edema.

• Other causes: Include tuberculous peritonitis (important in endemic areas), nephrotic syndrome, and pancreatic ascites. 2, 1

Initial Management Based on Severity

For Tense Ascites (Grade 3)

Perform therapeutic large-volume paracentesis as first-line treatment, removing all accessible fluid in a single session. 2, 3

• Albumin replacement: Administer 8 g of intravenous albumin per liter of ascites removed when removing >5 liters to prevent post-paracentesis circulatory dysfunction. 2, 3

• Large-volume paracentesis rapidly relieves tense ascites within minutes, compared to days or weeks with diuretics alone. 2

• After initial therapeutic paracentesis, initiate sodium restriction and oral diuretics to prevent reaccumulation. 2

For Moderate Ascites (Grade 2)

First-line treatment consists of sodium restriction (88 mmol per day or 2000 mg per day) combined with oral diuretics (spironolactone and furosemide). 2

Diuretic Regimen

• Initial dose: Start with spironolactone 100 mg daily (or 25 mg in heart failure patients) plus furosemide 40 mg daily. 2, 5

• Dose titration: Increase doses every 3-5 days until natriuresis and weight loss are achieved. 2

• Maximum doses: Spironolactone 400 mg/day and furosemide 160 mg/day. 2

• Monitoring: Check serum potassium, creatinine, and electrolytes regularly to detect hyperkalemia, hyponatremia, or azotemia. 2, 5

Sodium Restriction

• Target: 88 mmol (2000 mg) of sodium per day, equivalent to approximately 5 g of salt. 2

• No salt should be added at the table; patients should read labels on prepared foods to confirm daily intake. 2

• Fluid restriction is NOT necessary unless serum sodium falls below 120-125 mmol/L. 2

Critical Prognostic Information

The development of ascites signals poor prognosis, reducing 5-year survival from 80% in compensated cirrhosis to 30% in decompensated cirrhosis. 1, 3

Immediate Transplant Referral

All patients with ascites should be referred for liver transplantation evaluation immediately if cirrhosis is confirmed. 2, 3 This is the only curative option for cirrhotic ascites. 2

Monitoring and Follow-Up

• Frequency of follow-up: Patients warrant evaluation every 2-4 weeks until responding to treatment and not developing complications. 2

• Target weight loss: Aim for 0.5 kg/day in patients without peripheral edema, or 1 kg/day in those with edema. 2

• Urinary sodium excretion: Should exceed 78 mmol/day to indicate adequate diuresis. 2

Common Pitfalls to Avoid

• NSAIDs: Prostaglandin inhibitors reduce urinary sodium excretion and can convert diuretic-sensitive patients to refractory ascites. 2, 5 These should be strictly avoided.

• Overly aggressive diuresis: Can precipitate hepatic encephalopathy, acute kidney injury, or electrolyte disturbances. 6

• Delaying paracentesis for coagulopathy correction: This is unnecessary and delays critical diagnostic information. 1

• Initiating diuretics in hospitalized cirrhotic patients: In patients with cirrhosis and ascites, therapy is best initiated in the hospital setting with careful monitoring. 5, 6

Refractory Ascites

Refractory ascites is defined as fluid overload unresponsive to sodium restriction and maximum diuretic doses (400 mg spironolactone and 160 mg furosemide daily), or that recurs rapidly after therapeutic paracentesis. 2

Management options include:

• Serial therapeutic paracenteses: Performed approximately every 2 weeks with albumin replacement. 2

• Transjugular intrahepatic portosystemic shunt (TIPS): Effective in reducing need for repeated drainage but requires careful patient selection due to risk of hepatic encephalopathy. 2

• Palliative care referral: For patients not undergoing liver transplant evaluation. 2