Synopsis
Assess fluid by mechanism, recognise emergencies, relieve pressure safely and choose drainage, diuretics, compression or skin care according to cause, monitoring burden and goals.
- Ascites is free peritoneal fluid; peripheral oedema is interstitial fluid. Both are signs with malignant, portal-hypertensive, cardiac, renal, venous, lymphatic, drug and low-albumin causes.
- First-line assessment establishes onset, breathlessness, pain, fever, urine output, weight trend, medicines, liver and cardiac signs, unilateral versus bilateral swelling and the desired outcome.
- Urgently assess fever with abdominal pain, shock, new encephalopathy, oliguria, rapidly worsening dyspnoea, unilateral painful swelling or threatened skin.
- Ultrasound confirms and maps ascites before drainage; new, unexplained or clinically changed fluid usually needs diagnostic paracentesis when the result will alter care.
- The serum-ascites albumin gradient supports mechanism: 11 g/L or more favours portal hypertension, whereas a lower gradient favours peritoneal disease, but interpret in clinical context.
- Therapeutic paracentesis is first-line for rapid relief of tense, symptomatic malignant ascites; repeated procedures or a tunnelled catheter may suit recurrent fluid.
- In cirrhotic ascites, sodium moderation, spironolactone with or without furosemide and carefully monitored paracentesis follow a different pathway; give albumin after more than 5 litres according to the cirrhosis protocol.
- Diuretics are less predictably effective in pure peritoneal carcinomatosis and more likely to help when portal hypertension, heart failure or renal sodium retention contributes.
- Compression is not an automatic treatment for every swollen leg: first exclude acute DVT, severe arterial disease, decompensated heart failure, infection and fragile or leaking skin.
- The gold-standard plan names the mechanism, target symptom, expected time to benefit, biochemical and weight limits, escalation route and explicit stop point.
Key red flags
Fever, abdominal tenderness, new confusion, hypotension or rising creatinine with ascites suggests infected fluid even when pain is mild.
Severe breathlessness, hypoxia or inability to lie flat may reflect tense ascites, pleural fluid, pulmonary oedema or embolism and needs cause-focused assessment.
New oliguria, postural collapse, hyponatraemia or rapid creatinine rise may follow intravascular depletion despite visible oedema.
Unilateral painful leg swelling, chest pain or haemoptysis raises venous thromboembolism and should not be treated simply with elevation or compression.
Red, hot, tender or blistering oedematous skin suggests cellulitis, necrosis or severe pressure injury.
New ascites with weight loss, a pelvic mass or altered bowel habit requires diagnostic evaluation if disease-directed treatment remains an option.
Rapid diuretic escalation without renal, sodium, potassium, blood-pressure and weight review can precipitate encephalopathy, arrhythmia and kidney injury.
Abdominal pain, fever, hypotension, encephalopathy or renal decline in cirrhotic ascites requires urgent diagnostic tap and antibiotics.
Investigation priorities
Define observations, perfusion, weight trend, girth, jugular pressure, lungs, abdominal tension, pitting distribution, skin and unilateral features.
Management branches
Ascites or oedema is new, rapidly worse, painful, febrile or associated with breathlessness, confusion or oliguria.
- Assess ABCDE, sepsis, respiratory effect, perfusion, urine output, unilateral leg signs and skin; clarify escalation wishes without delaying immediate comfort.
- Obtain urgent bloods and ultrasound and perform diagnostic paracentesis promptly in cirrhosis or suspected peritonitis when safe; investigate DVT or cardiac failure as indicated.
- Treat infection, thrombosis or decompensated organ failure within goals and use monitored therapeutic drainage when pressure is causing severe symptoms.