Makindo Medical Notes

Related Subjects: |Chronic liver disease |Cirrhosis |Alkaline phosphatase (ALP) |Liver Function Tests |Ascites Assessment and Management |Budd-Chiari syndrome |Autoimmune Hepatitis |Primary Biliary Cirrhosis |Primary Sclerosing Cholangitis |Wilson disease |Hereditary Haemochromatosis |Alpha-1 Antitrypsin (AAT) deficiency |Non alcoholic steatohepatitis (NASH) |Spontaneous Bacterial Peritonitis |Alcoholism and Alcoholic Liver Disease

The Serum-Ascites Albumin Gradient (SAAG) is crucial for determining the cause of ascites. A SAAG ≥ 11 g/L suggests ascites due to portal hypertension, whereas a SAAG < 11 g/L points to causes such as malignancy or infections.

About Ascites

• Definition: Ascites is the abnormal accumulation of fluid in the peritoneal cavity.
• Common Causes: Liver cirrhosis (most common), malignancy, heart failure, nephrotic syndrome, and infections like tuberculosis.
• Presentation: Patients typically present with abdominal distension, discomfort, bloating, and in severe cases, dyspnea due to increased intra-abdominal pressure.

Aetiology

• Portal Hypertension: Increased pressure in the portal vein causes fluid transudation into the abdomen (common in cirrhosis).
• Hypoalbuminaemia: Low albumin decreases oncotic pressure, leading to fluid leakage (e.g., cirrhosis, nephrotic syndrome).
• Activation of the Renin-Angiotensin-Aldosterone (RAA) system: Sodium and water retention worsens fluid accumulation.
• Malignancy: Intra-abdominal cancers can cause peritoneal fluid buildup.

Clinical Features

• Distended Abdomen: A visibly swollen abdomen, often with dullness to percussion in the flanks (shifting dullness indicates free fluid).
• Shifting Dullness: Percuss the abdomen while the patient is supine and again after they roll onto their side; dullness shifts to the dependent side if ascites is present.
• Other Symptoms: Fatigue, bloating, and shortness of breath due to pressure on the diaphragm.

Investigations

• Serum-Ascites Albumin Gradient (SAAG): A SAAG ≥ 11 g/L suggests portal hypertension (e.g., cirrhosis); a SAAG < 11 g/L suggests other causes (e.g., malignancy, tuberculosis).
• Ascitic Fluid Analysis:
• Cell Count: Neutrophil count > 250 cells/mm³ indicates spontaneous bacterial peritonitis (SBP).
• Protein Level: Differentiates transudates from exudates.
• Cytology: Detects malignant cells if cancer is suspected.
• Glucose and Amylase: Low glucose suggests TB or malignancy; high amylase suggests pancreatitis.
• Gram Stain and Culture: To identify bacterial or TB infections.
• Ultrasound (USS): Can detect as little as 100-200 ml of fluid. Clinically detectable ascites requires approximately 1.5 L.

Management of Ascites

• Initial Measures: Bed rest, sodium restriction (2 g/day), and daily weights.
• Therapeutic Paracentesis: First-line treatment for patients with large or refractory ascites. Paracentesis of < 5 L of fluid generally does not require volume replacement.
• For large volume paracentesis (> 5 L), administer 8 g of 20% albumin per liter of ascites removed to prevent circulatory dysfunction.
• Diuretics: Spironolactone 50-400 mg/day and Furosemide 20-160 mg/day may be used in patients without hypovolemia.
• Close Monitoring: Regular checks for electrolytes and renal function (U&E) are essential, especially when using diuretics.
• TIPS (Transjugular Intrahepatic Portosystemic Shunt): Consider for refractory ascites unresponsive to paracentesis and medical therapy. TIPS reduces portal pressure by diverting blood flow away from the liver.
• Liver Transplant: Consider in eligible patients with cirrhosis and refractory ascites.
• Prophylactic Antibiotics: For patients with a history of spontaneous bacterial peritonitis (SBP), long-term prophylaxis with norfloxacin or ciprofloxacin is recommended.

Complications

• Spontaneous Bacterial Peritonitis (SBP): An infection of ascitic fluid, diagnosed when neutrophils > 250 cells/mm³. Treat with antibiotics (e.g., cefotaxime).
• Renal Failure: Hepatorenal syndrome can develop in patients with cirrhosis and ascites.
• Hepatic Hydrothorax: Fluid accumulation in the pleural cavity due to ascites.

References

• BSG Guidelines on Managing Ascites
• Human Albumin in the Management of Complications of Liver Cirrhosis