Ascites

• 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