Ascites ✅

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

💧 Serum–Ascites Albumin Gradient (SAAG) helps determine the cause of ascites by reflecting portal pressure: 👉 SAAG ≥ 1.1 g/dL (≥11 g/L) → portal hypertension (e.g. cirrhosis, cardiac ascites, Budd–Chiari). 👉 SAAG < 1.1 g/dL (<11 g/L) → non-portal causes (e.g. malignancy, TB, pancreatitis). 🧠 Key principle: SAAG correlates with sinusoidal pressure, not total protein.

📌 About Ascites

• 🧾 Definition: Pathological accumulation of fluid in the peritoneal cavity.
• 📊 Common causes: Cirrhosis (~80% in UK), malignancy, heart failure, TB, nephrotic syndrome.
• 😮‍💨 Presentation: Abdominal distension, discomfort, early satiety, dyspnoea (diaphragmatic splinting).

🧬 Pathophysiology (Exam Gold)

• 🫀 Portal hypertension: ↑ hydrostatic pressure → fluid transudation.
• 🧪 Splanchnic vasodilation: ↓ effective circulating volume → RAAS activation.
• 💊 RAAS activation: Na⁺/water retention → worsens ascites.
• 🧾 Hypoalbuminaemia: ↓ oncotic pressure (contributory, not primary driver).

🔎 Aetiology

• 🫀 Portal hypertension: Cirrhosis (most common), Budd–Chiari, right heart failure.
• 🧬 Peritoneal disease: Malignancy (carcinomatosis), TB.
• 🔥 Pancreatic: Pancreatitis (high amylase ascites).
• 🧪 Systemic: Nephrotic syndrome (low oncotic pressure).

👩‍⚕️ Clinical Features

• 🫃 Distended abdomen, bulging flanks.
• 🔄 Shifting dullness (>1–1.5 L fluid).
• 🌊 Fluid thrill (>2 L, less sensitive).
• Associated: peripheral oedema, muscle wasting, stigmata of chronic liver disease.

🧪 Investigations (BSG + NICE-aligned)

• 💉 Diagnostic paracentesis (ALL new ascites – BSG recommendation):
  • 🧫 Cell count: neutrophils ≥250/mm³ → SBP
  • 🧪 Albumin: calculate SAAG
  • 🧾 Total protein: helps differentiate cardiac vs cirrhotic
  • 🔬 Cytology if malignancy suspected
  • 🦠 Culture (inoculate into blood culture bottles at bedside)
  • 🧬 Amylase (pancreatitis), ADA (TB where relevant)
• 🖥️ Ultrasound: first-line (detects small volumes, guides tap)
• 🧲 CT/MR: if malignancy or unclear cause

💊 Management (BSG / NICE-aligned)

• 🍽️ Sodium restriction: ~2 g/day (no strict fluid restriction unless hyponatraemia)
• 💊 Diuretics:
  • First-line: spironolactone
  • Add furosemide if inadequate response
  • ⚠️ Monitor U&E, creatinine, K⁺ closely
• 💉 Large-volume paracentesis (tense ascites):
  • Give human albumin solution if >5 L removed
  • 💡 Dose: ~8 g albumin per litre drained
• 🔄 Refractory ascites:
  • Consider TIPS (if suitable)
  • Repeated paracentesis
• 🔪 Definitive: Liver transplantation (in cirrhosis)
• 🦠 SBP prophylaxis:
  • Indicated after prior SBP or high-risk patients
  • Typically ciprofloxacin (UK practice; norfloxacin less used)

⚠️ Complications

• 🦠 Spontaneous bacterial peritonitis (SBP)
• 🗂️ Hepatorenal syndrome
• 🌬️ Hepatic hydrothorax
• ⚡ Hyponatraemia

🧑‍⚕️ Case Corrections (Exam Accuracy)

• ❗ Important correction: Cirrhotic ascites should have HIGH SAAG (≥1.1 g/dL), not low.

🧑‍⚕️ Teaching Commentary

The key to ascites is understanding that portal hypertension—not low albumin—is the dominant driver in cirrhosis. Increased sinusoidal pressure leads to fluid transudation, while splanchnic vasodilation activates RAAS, perpetuating sodium retention and fluid accumulation. SAAG works because it reflects this pressure gradient rather than protein content, making it superior to older “transudate vs exudate” models. From a UK practice perspective, every new ascites should be tapped to exclude SBP, even if asymptomatic—this is a high-yield safety point. Finally, always think longitudinally: ascites in cirrhosis marks decompensation and should trigger consideration of transplant eligibility.

📚 References (NICE, BSG & Evidence-Based)

• 🇬🇧 BSG Guidelines (2021): Management of Ascites in Cirrhosis
  🔗 BSG Ascites Guideline
  Gold-standard UK guidance: diagnostic paracentesis, SAAG interpretation, albumin use, SBP management, and TIPS.
• 🇬🇧 NICE NG50: Cirrhosis in over 16s: assessment and management
  🔗 NICE NG50
  UK framework for cirrhosis complications including ascites, SBP risk, and referral for transplant.
• 🚨 NICE NG51: Sepsis: recognition and early management
  🔗 NICE NG51
  Essential for recognising and managing SBP and septic complications.
• 🧪 Runyon BA (1992, updated concepts): SAAG validation
  🔗 Serum–Ascites Albumin Gradient Study
  Seminal study establishing SAAG ≥1.1 g/dL as a marker of portal hypertension.
• 🌍 EASL Clinical Practice Guidelines (2018, updated): Decompensated Cirrhosis
  🔗 EASL Guidelines
  European guidance on ascites, SBP, albumin, and TIPS.
• 💉 Sort P et al. (1999): Albumin in SBP (NEJM)
  🔗 NEJM Albumin Trial
  Demonstrated reduced renal failure and mortality with albumin in SBP.
• 📘 Oxford Handbook of Clinical Medicine
  Concise UK clinical overview of ascites and SAAG interpretation.
• 📗 Davidson’s Principles and Practice of Medicine
  Core UK textbook for pathophysiology and management of liver disease.
• 📙 Robbins & Cotran Pathologic Basis of Disease
  Detailed mechanisms of portal hypertension and fluid accumulation.