How to evaluate and manage abdominal ascites?

Evaluation and Management of Abdominal Ascites

Perform diagnostic paracentesis with ascitic fluid analysis immediately in all patients with new-onset ascites or hospitalized patients with worsening ascites—this is the most rapid and cost-effective method to determine etiology and detect life-threatening complications like spontaneous bacterial peritonitis. 1

Initial Clinical Assessment

History and Physical Examination

• Assess for risk factors: alcohol use, viral hepatitis, heart failure, malignancy, tuberculosis, renal disease, and pancreatitis 1
• Key symptoms to elicit: recent weight gain, increased abdominal girth, ankle edema 2
• Physical examination findings:
  • Shifting dullness has 83% sensitivity and 56% specificity—requires approximately 1500 mL of fluid to be detectable 1
  • Perform flank percussion with patient supine; if dullness extends higher than normal on lateral abdomen, test for shifting 1
  • Fluid wave is more specific but less sensitive 2
  • Jugular venous distension suggests cardiac ascites rather than cirrhotic ascites 1
  • If no flank dullness present, patient has <10% chance of having ascites 1

When Ultrasound is Needed

• Required in obese patients where physical examination is unreliable 1
• Confirms presence of ascites when clinical findings are equivocal 1
• Evaluates liver appearance, splenomegaly (suggesting portal hypertension), pancreas, lymph nodes, and excludes portal/hepatic vein thrombosis 1

Diagnostic Paracentesis Technique

Indications (Mandatory)

• All patients with new-onset grade 2 or 3 ascites 1
• All hospitalized patients with worsening ascites or any complication of cirrhosis 1
• Admission surveillance to detect unexpected infection (15% prevalence of spontaneous bacterial peritonitis in hospitalized cirrhotic patients) 1

Procedure Details

• Site: Approximately 15 cm lateral to umbilicus in left or right lower quadrant 1
• Avoid: Enlarged liver/spleen and inferior/superior epigastric arteries (run lateral to umbilicus toward mid-inguinal point) 1
• Volume: Withdraw 10-20 mL for diagnostic purposes 1
• Safety: Complications occur in only ~1% (abdominal wall hematomas); serious complications (hemoperitoneum, bowel perforation) are rare (1/1000) 1

Critical Point on Coagulopathy

Do NOT routinely give fresh frozen plasma or platelets before paracentesis despite abnormal coagulation tests—71% of patients have abnormal PT but bleeding complications remain rare. 1 Consider platelets only if platelet count <40,000/mm³ 1. Patients with cirrhosis have balanced deficiency of procoagulants and anticoagulants, so routine coagulation tests don't reflect actual bleeding risk 1.

Essential Ascitic Fluid Analysis

Mandatory Tests (Send on ALL Patients)

1. Serum-Ascites Albumin Gradient (SAAG):

   • SAAG ≥11 g/L (or ≥1.1 g/dL) = portal hypertension with 97% accuracy 1
   • SAAG <11 g/L = non-portal hypertensive causes (peritoneal carcinomatosis, tuberculosis, pancreatitis, nephrotic syndrome) 1

2. Ascitic fluid neutrophil count:

   • >250 cells/mm³ = spontaneous bacterial peritonitis (SBP) 1
   • Each hour delay in diagnostic paracentesis increases in-hospital mortality by 3.3% 1
   • SBP mortality has decreased from 90% to 20% with early diagnosis 1

3. Ascitic fluid culture:

   • Inoculate 10 mL into blood culture bottles at bedside to enhance sensitivity 1
   • Use two blood culture bottles 1

4. Total protein concentration:

   • <15 g/L (or <1.5 g/dL) indicates increased risk of SBP 1

Optional Tests (Based on Clinical Suspicion)

• Amylase: if pancreatitis suspected 1
• Cytology: if malignancy suspected (30% of bloody ascites in cirrhotics have hepatocellular carcinoma) 1
• Mycobacterial culture/PCR: if tuberculosis suspected 1

Blood Tests Required

• Urea and electrolytes 1
• Liver function tests 1
• Prothrombin time 1
• Complete blood count 1
• Brain natriuretic peptide (BNP): if cardiac ascites suspected—median pro-BNP is 6100 pg/mL in heart failure vs. 166 pg/mL in cirrhosis 1

Management Based on Etiology

Portal Hypertensive Ascites (SAAG ≥11 g/L)

Sodium restriction and diuretics are the cornerstone of treatment. 3

First-Line Diuretic Therapy

• Start spironolactone as the basic drug—it has greater natriuretic potency than loop diuretics in patients with marked sodium retention 4
• Add furosemide simultaneously to increase natriuretic effect and balance potassium metabolism 4
• Establish routine pattern for taking spironolactone with meals (food increases bioavailability by 95.4%) 5

Monitoring and Precautions

• Monitor serum potassium within 1 week of initiation or dose titration, then regularly 5
• Risk of hyperkalemia increased with renal impairment, potassium supplements, ACE inhibitors, ARBs, NSAIDs 5
• Monitor for hypotension, worsening renal function, hyponatremia, and gynecomastia (9% incidence in males, dose-dependent) 5
• In hepatic cirrhosis, initiate therapy in hospital due to risk of hepatic coma with sudden fluid/electrolyte shifts 6

Large-Volume (Tense) Ascites

Large-volume paracentesis with intravenous albumin is the treatment of choice—more effective than diuretics alone, with lower complication rates and shorter hospital stays. 4

• Indicated for ascites >5 liters 7
• Must give albumin infusion to prevent circulatory dysfunction, renal impairment, and severe hyponatremia 4
• Dextran 70 and polygeline appear as effective as albumin 4
• Patients still require diuretics after paracentesis to prevent reaccumulation 4

Refractory Ascites

• Defined as ascites unresponsive to sodium restriction and intensive diuretics, or recurs ≥3 times within 12 months 1
• Options include repeated large-volume paracentesis or transjugular intrahepatic portosystemic shunt (TIPS) 3
• Consider liver transplantation evaluation—development of ascites drops 5-year survival from 80% to 30% 1

Critical Pitfalls to Avoid

1. Never assume alcoholic patients have alcoholic liver disease—always investigate other causes 1
2. Do not delay paracentesis for coagulopathy correction—routine FFP/platelet transfusion is not data-supported 1
3. Never perform paracentesis without plasma volume expansion for large volumes—constantly associated with circulatory deterioration 4
4. Do not miss SBP—15% prevalence at hospital admission, and mortality increases 3.3% per hour of diagnostic delay 1
5. Avoid NSAIDs in cirrhotic ascites—can reduce diuretic efficacy and worsen renal function 5