Ascites

Physical Examination

• General examination:

• Observe the patient for any signs of discomfort or pain.

• Check for pallor, suggesting chronic disease or anaemia.

• Look for jaundice, indicative of liver disease.

• Note any signs of dehydration, including dry mucous membranes, sunken eyes, or poor skin turgor.

• Examination of the hands:

• Note any asterixis (flapping tremor), which could suggest hepatic encephalopathy.

• Observe palmar erythema and Dupuytren's contracture, seen in liver disease.

• Look for signs of hypoalbuminemia, such as nail clubbing and white nails (leukonychia).

• Examination of the arms:

• Check for muscle wasting, indicative of chronic illness.

• Examination of the mouth:

• Examine for signs of spider naevi, indicative of liver disease.

• Note any evidence of fetor hepaticus (a musty breath odour), suggestive of liver disease.

• Inspection of the abdomen:

• Look for distention, consistent with ascites.

• Note any visible collateral veins or caput medusae, suggesting portal hypertension.

• Look for scars from previous surgery.

• Palpation of the abdomen:

• Test for shifting dullness or fluid wave, indicating free fluid in the abdomen.

• Look for any hepatomegaly or splenomegaly.

• Percussion of the abdomen:

• Confirm ascites by identifying shifting dullness.

• Check for a fluid thrill if initial findings are suggestive.

• Auscultation of the abdomen:

• Listen for diminished bowel sounds suggestive of paralytic ileus or peritonitis.

• Additional examinations:

• If appropriate, perform a rectal examination to identify rectal varices, melena, or other signs of gastrointestinal bleeding.

• Consider examining other systems, such as the cardiovascular system, for signs of right heart failure or the respiratory system for signs of pleural effusion, both of which may coexist in a patient with ascites.

Investigations

• Laboratory investigations:

  • Complete blood count: To look for anaemia or evidence of infection.

  • Liver function tests: To assess liver function and evaluate for liver disease.

  • Renal function tests: To evaluate kidney function, renal disease can also cause ascites.

  • Serum electrolytes: To assess for any electrolyte imbalances, which may be seen in liver or kidney disease.

  • Coagulation profile: Liver disease can cause coagulopathy.

  • Serum albumin: Low levels can suggest liver disease or malnutrition, both of which can cause ascites.

  • Viral hepatitis serology: Hepatitis B and C can cause liver disease leading to ascites.

• Imaging:

  • Abdominal ultrasound: To visualise any free fluid in the peritoneal cavity and assess the liver, spleen, and kidneys.

  • CT abdomen: For a more detailed view of the abdominal organs and to identify any malignancies or other pathologies.

  • Chest X-ray: To rule out pleural effusion or other lung diseases that can occur alongside ascites.

• Invasive investigations:

  • Paracentesis: To examine the ascitic fluid for protein levels, cell counts, and cytology. This is the most direct way to diagnose and classify ascites.

    • High protein (>2.5g/dL) and white cell count (>500/mm^3 or >250 polymorphonuclear cells/mm^3) could suggest bacterial peritonitis.

    • High serum-ascites albumin gradient (SAAG > 1.1 g/dL) indicates portal hypertension, often due to liver cirrhosis.

    • Low SAAG (<1.1 g/dL) suggests ascites due to other causes like malignancy, tuberculosis, and pancreatitis.

  • Liver biopsy: If the cause of ascites remains unclear or to confirm a diagnosis of liver disease.

• Other tests:

  • Echocardiogram: If a cardiac cause of ascites (like right-sided heart failure) is suspected.

  • Endoscopy: If varices are suspected, an upper GI endoscopy might be performed to visualise them directly.

Management

• General management:

  • Dietary advice: Recommend a low-sodium diet to help reduce fluid build-up.

  • Fluid restriction: If serum sodium is very low (<125 mmol/L).

  • Weight monitoring: Regular weight checks can help monitor the effectiveness of treatment.

  • Vaccinations: Immunizations for pneumococcus, influenza, and hepatitis B should be considered due to increased infection risk.

• Medical management:

  • Diuretics: Spironolactone or furosemide can increase fluid excretion.

  • Antibiotics: If spontaneous bacterial peritonitis (SBP) is confirmed or suspected, antibiotics like cefotaxime are used.

  • Lactulose: To prevent or treat hepatic encephalopathy if present.

  • Beta-blockers: Such as propranolol can be used to decrease portal pressure, which is useful in cases of portal hypertension.

• Surgical management:

  • Large volume paracentesis: If symptomatic relief is needed immediately, removal of fluid can be done. Albumin is often given afterwards to prevent post-paracentesis circulatory dysfunction.

  • Transjugular intrahepatic portosystemic shunt (TIPS): This procedure can relieve portal hypertension by creating a new path for blood flow and reducing fluid accumulation. It's usually reserved for refractory cases.

• Other management:

  • Alcohol cessation counselling: For those with alcoholic liver disease.

  • Liver transplant evaluation: For those with advanced liver disease.

  • Endoscopic band ligation: If oesophagal varices are present, they may need to be treated to prevent rupture and bleeding.

  • Regular follow-ups: Ascites can signify advanced disease, and regular monitoring is necessary to assess response to treatment and adjust management as needed.

What is Serum-Ascites Albumin Gradient (SAAG)?

The Serum-Ascites Albumin Gradient (SAAG) is determined using the formula:

SAAG = [Serum Albumin] - [Ascitic Fluid Albumin]

Here's how the gradient helps to diagnose the cause of ascites:

• SAAG > 1.1 g/dL: Indicates ascites is likely due to portal hypertension. This condition is typically caused by cirrhosis, heart failure, Budd-Chiari syndrome, or portal vein thrombosis.

• SAAG < 1.1 g/dL: Suggests ascites is not a result of portal hypertension. The sources of this can be a malignancy, pancreatitis, or tuberculosis, among other conditions.