Ascites - Medical Lecture Notes
Definition
Ascites is the pathological accumulation of fluid in the peritoneal cavity, most commonly due to portal hypertension caused by liver cirrhosis. It is a key sign of advanced liver disease, though other causes must be considered.
Pathophysiology
- Portal Hypertension: Increased hydrostatic pressure due to cirrhosis causes fluid leakage into the peritoneal space.
- Hypoalbuminemia: Reduced plasma oncotic pressure from impaired hepatic albumin synthesis allows fluid to leak out of capillaries.
- Splanchnic Vasodilation: Nitric oxide release causes vasodilation, further reducing effective circulating volume.
- RAAS Activation: Sodium and water retention worsens fluid accumulation.
Common Causes of Ascites
- Cirrhosis (≈ 80% of cases)
- Malignancy (Peritoneal carcinomatosis, lymphomas)
- Infectious: Tuberculosis peritonitis
- Nephrotic syndrome
- Congestive heart failure
- Pancreatitis
- Chylous ascites (lymphatic obstruction)
Clinical Presentation
- Progressive abdominal distension
- Early satiety
- Shortness of breath (due to diaphragmatic pressure)
- Shifting dullness, fluid thrill
- Peripheral edema (if hypoalbuminemia is present)
Diagnostic Work-up
- History & Physical Examination
- Ultrasound Abdomen: Most sensitive for small amounts of fluid (>100 ml)
- Diagnostic Paracentesis: Always performed in new-onset ascites, suspected infection or deterioration.
Ascitic Fluid Analysis
- Appearance: Clear (transudate), cloudy/purulent (infection), bloody (malignancy/TB)
- Serum Ascites Albumin Gradient (SAAG):
- SAAG ≥1.1 g/dL → suggests portal hypertension (cirrhosis, CHF)
- SAAG <1.1 g/dL → suggests non-portal hypertensive causes (TB, cancer, pancreatitis)
- Cell count & differential: Neutrophils >250/mm³ suggest spontaneous bacterial peritonitis (SBP)
- Culture, glucose, LDH, cytology, AFB if TB suspected
Types of Ascites
- Transudative Ascites – Low protein content (e.g., cirrhosis, nephrotic syndrome)
- Exudative Ascites – High protein content (e.g., TB, malignancy, pancreatitis)
- Hemorrhagic Ascites – Bloody ascitic fluid (e.g., trauma, malignancy)
- Chylous Ascites – Milky appearance due to lymph (e.g., lymphoma, TB, filariasis)
Complications
- Spontaneous Bacterial Peritonitis (SBP): Life-threatening infection of ascitic fluid
- Hepatorenal Syndrome (HRS)
- Respiratory compromise
- Malnutrition and sarcopenia
Management
- General Measures: Salt restriction (<2g/day), fluid restriction if hyponatremic
- Diuretics:
- Spironolactone (first-line)
- Furosemide added if needed (typical ratio 100:40 mg)
- Therapeutic Paracentesis: For tense ascites; replace albumin if large volume removed
- SBP Treatment: Empirical IV cefotaxime; prophylactic norfloxacin in high-risk cases
- Refractory Ascites: TIPS (Transjugular Intrahepatic Portosystemic Shunt)
- Definitive treatment: Liver transplant
Prognosis
Ascites indicates decompensated liver disease. Median survival is approximately 2 years without transplant, especially if refractory or complicated by SBP or hepatorenal syndrome.
Important Clinical Points
- Always analyze ascitic fluid when new or worsening ascites appears.
- Monitor renal function and electrolytes frequently during diuretic therapy.
- SBP can be asymptomatic; always have a high index of suspicion.
References & Resources
- Harrison's Principles of Internal Medicine
- Davidson's Principles and Practice of Medicine
- Oxford Handbook of Clinical Medicine
- Uptodate: Evaluation of ascites in adults
- American Association for the Study of Liver Diseases (AASLD) Guidelines
Created for medical education. For any personal health concerns, consult a licensed physician.
إرسال تعليق