- Sodium and water retention - peripheral arterial vasodilation which causes a reduction in BV. This reduction activates the RAAS promoting retention
- Portal hypertension - local hydrostatic pressure leading to increase hepatic and splanchnic production of lymph and transduction of fluid into the peritoneal cavity. A high SAAG gradient (> 11g/L) indicates portal hypertension
- Low serum albumin (due to poor liver function) further reduces plasma oncotic pressure
| Straw-coloured | * Malignancy (most common) * Cirrhosis * Infective (TB, perforation) * Hepatic vein obstruction * Chronic pancreatitis * CCF * Hypoproteinaemia (nephrotic syndrome) |
|---|---|
| Chylous | * Obstruction of main lympatic duct (eg by carcinoma) - chylomicrons are present * Cirrhosis |
| Haemorrhagic | * Malignany * Ruptured ectopic Pregnancy * Abdo trauma * Acute pancreatitis |
Urine sodium rarely exceeds 5mmol/24hr and extrarenal sites account for ≈ 30mmol/24hr. Under these circumstances a normal sodium intake of 120-200mmol results in a positive sodium balance of 90-170mmol (600-1300mL of fluid retained)
Aim to reduce sodium intake and increase renal excretion
- Dietary sodium restriction
- Main drugs contain significant amount of sodium (if they are in a salt form) esp antacids and antibiotics. Sodium retaining drugs include NSAIDs and corticosteroids
- Diuretics - spironolactone 100mg daily - aim to produce a net loss of 700ml fluid a day
Paracentesis used to treat symptomatic tense ascites or when diuretic therapy is insufficient