Ascites

Question 1

What is ascites?

Answer 1

• Ascites: pathological collection of fluid in peritoneal cavity
• Most common cause is cirrhosis (approx 75% cases)
• > 25ml of fluid in peritoneal cavity

Question 2

Ascites: transudate vs exudate?

Answer 2

Transudate causes (low albumin, but fluid leaves due to portal HTN, therefore high gradient) >11g/ L
- IF <25g/ L: more likely likely cirrhosis/ metastases
- IF >25g/ L: more likely congestive cardiac failure, right-sided heart failure, constrictive pericarditis

Exudate causes (actively secreted protein into peritoneal cavity; high albumin therefore albumin content similar to that of serum→ lower gradient) <11g/ L
- Infection (TB, HIV, SBP)
- Malignancy (Abdominal, pelvic)

Question 3

Ascites: clinical features and relevant investigations?

Answer 3

Abdominal distension

Physical exam→ shifting dullness (1)

USS/ CT/ MRI can confirm diagnosis (2)

Diagnostic abdo paracentesis: indicated for those w new-onset ascites upon hospital admission/ clinical deterioration (i.e: fever, abdo pain, mental status change, ileus, hypotension)/ GI bleeding/ any laboratory sign of infection (3)

When liver cirrhosis suspected and clinical presentation not clear→ liver biopsy may detect/ rule out cirrhosis as cause of ascites (4)

May have signs of chronic liver disease/ cardiac failure

Question 4

Main cause of ascites and assoc pathophysiology?

Answer 4

Sodium retention major factor in pathogenesis→ water retention→ increased resistance to portal flow→ portal HTN, collateral vein formation and shunting of systemic circulation

Question 5

Non-peritoneal aetiologies of ascites? (more common)

Answer 5

Conditions causing portal HTN: cirrhosis, alcoholic liver disease, fulminant hepatitis, subacute hepatitis, massive liver metastasis, congestive heart failure, constrictive pericarditis, Budd-Chiari syndrome

Conditions causing hypo-albuminaemia: nephrotic syndrome, etc

Miscellaneous: myxoedema, ovarian tumours, pancreatic ascites, urogenital surgical trauma

Question 6

Peritoneal aetiologies of ascites? (less common)

Answer 6

Malignant ascites: peritoneal mesothelioma, ovarian cancer, etc

Infectious peritonitis: TB,Chlamydia, fungal and parasitic infections (Candida albicans,Histoplasma capsulatum,etc).
- Primary peritonitis (rare): caused by spread of infection from blood and lymph nodes to peritoneum
- Secondary peritonitis: infection from gastrointestinal/ biliary tracts; more common

Other peritoneal diseases: SLE

Question 7

Urgent considerations in ascites? (5)

Answer 7

1) Most important: spontaneous bacterial peritonitis; infection of previously sterile ascitic fluid without apparent intra-abdominal source of infection

2) Haemoperitoneum may be due to internal trauma/ may occur in some w hepatocellular carcinoma. Requires transcatheter arterial embolisation

3) Refractory ascites (max diuretic doses not sufficient/ adverse effects and complications)→ manage w large-vol paracentesis and albumin replacement

4) Hepatic encephalopathy (ascites due to cirrhosis): can initially be very subtle (i.e: change in handwriting, altered sleep pattern→ confusion, coma). Needs prompt treatment w lactulose and rifaximin

5) Worsening renal function in patient w ascites may be due to hepatorenal syndrome→ urgent treatment

Question 8

Management of ascites?

Answer 8

Treat underlying cause

High SAAG (serum-ascites albumin gradient)
- Low dietary salt
- If hyponatraemic - fluid restrict
- Diuretics (spironolactone/ both)
- Spironolactone - blocks aldosterone receptor (reduce reabsorption of Na)
- Furosemide (loop diuretic)
- Paracentesis
- Monitor weight

Low SAAG
- Repeated paracentesis

Spontaneous bacterial peritonitis: IV ABs (cefuroxime and metronidazole) + IV albumin

Question 9

What is hepatorenal syndrome?

Answer 9

• Vasodilation due to low albumin + portal HTN
• Reduction in perfusion to kidney→ vasoconstriction of renal artery
• Activation of RAS system→ increased water retention due to increased aldosterone→ worsening ascites