Ascites
Summary
Ascites is the pathological accumulation of fluid in the peritoneal cavity. Cirrhosis with portal hypertension is the most common cause (75-85%), followed by malignancy, heart failure, and other causes. The serum-ascites albumin gradient (SAAG) differentiates portal hypertensive causes (SAAG ≥11 g/L) from non-portal causes (SAAG less than 11 g/L). Management of cirrhotic ascites involves sodium restriction, diuretics (spironolactone ± furosemide), and therapeutic paracentesis for tense or refractory ascites. Spontaneous bacterial peritonitis (SBP) is a life-threatening complication requiring prompt recognition and antibiotic treatment.
Key Facts
- Prevalence: 60% of cirrhotic patients develop ascites within 10 years
- Most common cause: Cirrhosis (75-85%)
- SAAG ≥11: Portal hypertension (cirrhosis, cardiac, Budd-Chiari)
- SAAG less than 11: Non-portal (malignancy, TB, pancreatitis, nephrotic)
- Mortality: 50% 2-year mortality in cirrhosis with ascites
- Key treatment: Salt restriction + Spironolactone ± Furosemide
Clinical Pearls
The SAAG Rule: SAAG ≥11 g/L = portal hypertension (treat like cirrhosis). SAAG less than 11 g/L = exudative (investigate for malignancy, TB, other causes). SAAG is more accurate than the outdated transudate/exudate classification.
Tap Early, Tap Often: Any patient with cirrhosis presenting unwell should have a diagnostic paracentesis to exclude SBP. Fever, abdominal pain, encephalopathy, and worsening renal function are often the only signs.
The 100:40 Ratio: Spironolactone 100mg to furosemide 40mg is the traditional starting ratio. Increase together to maintain sodium and potassium balance.
Why This Matters Clinically
Development of ascites marks decompensated cirrhosis — a significant prognostic milestone. Early detection and treatment of SBP prevents sepsis and hepatorenal syndrome. Refractory ascites requires consideration for TIPS or liver transplant referral.
Incidence & Prevalence
- In cirrhosis: 60% develop ascites within 10 years of diagnosis
- First decompensation: Ascites is the most common first decompensation event
- Prevalence: Ascites affects ~5% of hospitalised patients
Demographics
| Factor | Details |
|---|---|
| Age | Increases with age (cirrhosis, cardiac causes) |
| Sex | Reflects underlying cause (alcohol-related in males) |
| Ethnicity | Varies with cirrhosis prevalence |
| Geography | Higher in regions with high alcohol or viral hepatitis rates |
Causes of Ascites
| SAAG ≥11 g/L (High Gradient) | SAAG less than 11 g/L (Low Gradient) |
|---|---|
| Cirrhosis (75-85%) | Peritoneal carcinomatosis |
| Cardiac failure | Tuberculous peritonitis |
| Budd-Chiari syndrome | Pancreatic ascites |
| Portal vein thrombosis | Nephrotic syndrome |
| Myxoedema | Serositis (e.g., SLE) |
| Massive liver metastases | Bowel obstruction or infarction |
Mechanism (Cirrhotic Ascites)
Step 1: Portal Hypertension
- Cirrhosis increases intrahepatic resistance
- Portal pressure rises (HVPG greater than 10 mmHg = clinically significant)
- Splanchnic vasodilatation occurs
Step 2: Arterial Underfilling
- Splanchnic vasodilatation leads to relative hypovolaemia
- Activates RAAS, sympathetic nervous system, ADH
- Sodium and water retention
Step 3: Fluid Shifts
- Hydrostatic pressure forces fluid into peritoneum
- Low oncotic pressure (hypoalbuminaemia) exacerbates transudation
- Lymphatic drainage capacity exceeded
Step 4: Ascites Formation
- Net fluid accumulation in peritoneal cavity
- Sodium retention perpetuates fluid accumulation
Classification
| Grade | Description | Clinical Features |
|---|---|---|
| Grade 1 | Mild | Detected only by USS |
| Grade 2 | Moderate | Visible distension, shifting dullness |
| Grade 3 | Severe (Tense) | Marked distension, tense abdomen, respiratory compromise |
Symptoms
Signs
Red Flags
[!CAUTION] Red Flags — Urgent investigation and treatment if:
- Fever, abdominal pain, or tenderness (SBP)
- Worsening encephalopathy
- Rising creatinine (hepatorenal syndrome)
- Respiratory distress (tense ascites)
- Bloody ascites (malignancy, trauma)
Structured Approach
Abdominal:
- Inspect: Distension, everted umbilicus, dilated veins (caput medusae)
- Palpate: Tenderness (SBP), hepatosplenomegaly
- Percuss: Shifting dullness, fluid thrill
- Auscultate: Bowel sounds (exclude ileus)
Cardiovascular:
- JVP (cardiac ascites)
- Peripheral oedema
Stigmata of Chronic Liver Disease:
- Jaundice, spider naevi, palmar erythema
- Gynaecomastia, testicular atrophy
- Encephalopathy (asterixis)
Special Tests
| Test | Technique | Positive Finding | Purpose |
|---|---|---|---|
| Shifting dullness | Percuss flanks; reposition patient | Dullness moves to dependent side | Detect moderate ascites |
| Fluid thrill | Tap one flank; feel opposite | Impulse transmitted | Large volume ascites |
| Puddle sign | Knee-elbow position; percuss umbilicus | Central dullness | Detect small volumes (rarely used) |
First-Line
- Diagnostic paracentesis — All new ascites or hospital admission
- Ascitic fluid analysis — Cell count, albumin, culture
Ascitic Fluid Analysis
| Test | Interpretation |
|---|---|
| Cell count (WCC) | Neutrophils ≥250/mm³ = SBP |
| Albumin | Calculate SAAG |
| SAAG | ≥11 g/L = portal hypertension |
| Culture | Identify organism in SBP |
| Cytology | If malignancy suspected |
| Protein | Low (<5 g/L) = high SBP risk; primary prophylaxis indicated |
Laboratory Tests
| Test | Expected Finding | Purpose |
|---|---|---|
| LFTs | Deranged in liver disease | Assess liver function |
| Albumin | Low in cirrhosis | Calculate SAAG |
| U&Es | Hyponatraemia, renal impairment | Monitor electrolytes, renal function |
| INR | Prolonged in cirrhosis | Coagulopathy assessment |
| FBC | Thrombocytopenia, leukopenia (hypersplenism) | Portal hypertension |
Imaging
| Modality | Findings | Indication |
|---|---|---|
| Ultrasound | Free fluid, liver appearance, spleen size | First-line |
| CT abdomen | Characterise ascites, exclude malignancy | If USS inconclusive or malignancy suspected |
| Doppler | Portal vein, hepatic vein patency | Exclude Budd-Chiari, PVT |
| Echo | Cardiac function | If cardiac ascites suspected |
Management Algorithm
NEW ASCITES
↓
┌─────────────────────────────────────────┐
│ DIAGNOSTIC PARACENTESIS │
│ Cell count, albumin, culture │
└─────────────────────────────────────────┘
↓
┌─────────────────────────────────────────┐
│ CALCULATE SAAG │
├─────────────────────────────────────────┤
│ SAAG ≥11 → Portal hypertension │
│ (Cirrhosis, cardiac) │
│ SAAG <11 → Non-portal │
│ (Malignancy, TB, other) │
└─────────────────────────────────────────┘
↓
┌─────────────────────────────────────────┐
│ CIRRHOTIC ASCITES │
├─────────────────────────────────────────┤
│ 1. Salt restriction (<2g/day) │
│ 2. Spironolactone 100mg OD │
│ ± Furosemide 40mg OD │
│ 3. Fluid restrict if Na <125 │
│ 4. Titrate diuretics (max 400/160) │
└─────────────────────────────────────────┘
↓
┌─────────────────────────────────────────┐
│ REFRACTORY ASCITES │
├─────────────────────────────────────────┤
│ 1. Therapeutic paracentesis + albumin │
│ 2. Consider TIPS │
│ 3. Liver transplant assessment │
└─────────────────────────────────────────┘
Conservative Management
- Sodium restriction: Less than 2g (88 mmol) per day
- Fluid restriction: Only if severe hyponatraemia (Na less than 125)
- Avoid NSAIDs: Reduce renal perfusion
- Alcohol abstinence: Essential if alcohol-related
Medical Management
| Drug | Starting Dose | Max Dose | Notes |
|---|---|---|---|
| Spironolactone | 100mg OD | 400mg OD | First-line; monitor K+ |
| Furosemide | 40mg OD | 160mg OD | Add if insufficient response |
| Albumin | 8g per litre drained (if >L) | — | Prevents circulatory dysfunction |
Diuretic Monitoring:
- Weight loss: Target 0.5kg/day (no oedema) or 1kg/day (with oedema)
- Monitor: U&Es, creatinine (stop if AKI develops)
Therapeutic Paracentesis
Indications:
- Tense/symptomatic ascites
- Refractory ascites
- Respiratory compromise
Technique:
- Large-volume paracentesis (LVP): Drain to dryness
- Give albumin if more than 5L drained (8g per litre removed)
- Can be repeated as needed
TIPS (Transjugular Intrahepatic Portosystemic Shunt)
Indications:
- Refractory ascites
- Frequent need for LVP
Contraindications:
- Severe hepatic encephalopathy
- Very poor liver function (MELD greater than 18)
- Cardiac failure
Disposition
- Admit if: SBP, tense ascites with symptoms, new encephalopathy, renal impairment
- Discharge if: Stable on diuretics, community drainage arranged if needed
- Follow-up: Weekly weight; regular U&Es; hepatology
Immediate
| Complication | Incidence | Presentation | Management |
|---|---|---|---|
| SBP | 10-30% per year | Fever, pain, encephalopathy | IV cefotaxime, albumin |
| Respiratory compromise | Tense ascites | Dyspnoea, hypoxia | Therapeutic paracentesis |
Early (Weeks)
- Electrolyte disturbance: Hypokalaemia (furosemide), hyperkalaemia (spironolactone)
- Renal impairment: Over-diuresis, hepatorenal syndrome
- Hyponatraemia: Dilutional
Late (Months-Years)
- Hepatorenal syndrome: Type 1 (rapid) or Type 2 (slower)
- Umbilical hernia complications: Incarceration, rupture, ulceration
- Malnutrition: Protein loss, poor intake
Outcomes
| Variable | Outcome |
|---|---|
| 2-year survival (cirrhosis + ascites) | 50% |
| Response to diuretics | 90% |
| Refractory ascites | 10% (poor prognosis) |
| Post-SBP mortality | 30-50% at 1 year |
Prognostic Factors
Good Prognosis:
- First episode
- Good liver function (Child-Pugh A)
- Response to diuretics
- No SBP
Poor Prognosis:
- Refractory ascites
- Hepatorenal syndrome
- Recurrent SBP
- High MELD score
- Hyponatraemia
Key Guidelines
- EASL Clinical Practice Guidelines on Decompensated Cirrhosis (2018) — European Association for the Study of the Liver. J Hepatol 2018
- AASLD Practice Guidance on Ascites and HRS (2021) — American Association for the Study of Liver Diseases.
- BSG Guidelines on Ascites — British Society of Gastroenterology.
Key Trials
ANSWER Trial (2018) — Albumin for long-term ascites management
- 431 patients
- Key finding: Weekly albumin infusions improved 18-month survival
- Clinical Impact: Supports long-term albumin use in refractory ascites
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| Spironolactone + furosemide | 1b | Multiple RCTs |
| Albumin with LVP | 1a | Cochrane review |
| TIPS for refractory | 1b | RCTs |
| Long-term albumin | 1b | ANSWER Trial |
What is Ascites?
Ascites is a build-up of fluid in your tummy (abdomen). It usually happens when your liver isn't working properly (cirrhosis) but can also be caused by heart problems or cancer.
Why does it matter?
Fluid build-up can make you uncomfortable, short of breath, and affect your appetite. It is also a sign that your liver or heart is not working well. Sometimes the fluid can become infected (called SBP), which is serious and needs urgent treatment.
How is it treated?
- Reduce salt: Eating less salt helps prevent more fluid building up.
- Water tablets (diuretics): Medications like spironolactone help your body get rid of extra fluid.
- Draining fluid: If there is a lot of fluid, doctors can remove it with a needle (paracentesis).
- Treating the cause: If liver disease is the cause, avoiding alcohol and treating hepatitis is essential.
What to expect
- You will need regular blood tests to check kidney function and salt levels
- Fluid may need to be drained more than once
- Weight is monitored to track fluid loss
- Some people need a special procedure called TIPS or a liver transplant
When to seek help
See a doctor urgently if you have:
- Fever or abdominal pain
- Increasing confusion or drowsiness
- Rapid weight gain or worsening swelling
- Difficulty breathing
Primary Guidelines
- European Association for the Study of the Liver. EASL Clinical Practice Guidelines for the management of patients with decompensated cirrhosis. J Hepatol. 2018;69(2):406-460. PMID: 29653741
Key Studies
- Runyon BA. Management of adult patients with ascites due to cirrhosis: update 2012. Hepatology. 2013;57(4):1651-3. PMID: 23463403
- Caraceni P, et al. Long-term albumin administration in decompensated cirrhosis (ANSWER). Lancet. 2018;391(10138):2417-2429. PMID: 29861076
Further Resources
- British Liver Trust: britishlivertrust.org.uk
- NHS Ascites: nhs.uk/conditions/ascites
Last Reviewed: 2025-12-24 | MedVellum Editorial Team
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.