ASCITES

Question 1

Overview (4)

Answer 1

• Presence of fluid in the peritoneal cavity
• Cirrhosis is commonest cause
• Cirrhosis —> peripheral arterial vasodilatation —> reduction in effective blood volume, activation of the sympathetic nervous system and RAAS —> renal salt and water retention (also encouraged by hypoalbuminemia)
• Mainly localized to the peritoneal cavity as a result of the portal hypertension

Question 2

Clinical Features (4)

Answer 2

• Fullness in the flanks with shifting dullness and fluid thrill
• Tense ascites is uncomfortable and produces respiratory distress
• Pleural effusion (usually right-sided) and peripheral edema may also be present
• Meigs syndrome: triad of benign ovarian fibroma, ascites, and pleural effusion

Question 3

Investigations (6)

Answer 3

Ascitic fluid diagnostic aspiration: 10-20mL of ascitic fluid tested for:
- Albumin: for measurement of SAAG* (serum albumin - ascites albumin)
- Total protein**
- Neutrophil count: if >250 cells/mm3 —> spontaneous bacterial peritonitis
- Gram stain and culture for bacteria and acid-fast bacilli
- Cytology for malignant cells
- Amylase to exclude pancreatic ascites

Question 4

Serum albumin - ascitic albumin (SAAG) ratio

Answer 4

Differentiates between different causes of ascites (Transudate vs Exudate). A high gradient (SAAG > 11.1g/L) indicates portal hypertension and suggests a non-peritoneal cause of ascites

Question 5

SAAG < 11.1 g/L (Exudate) (5)

Answer 5

• Peritoneal carcinomatosis
• Peritoneal tuberculosis
• Pancreatitis
• Nephrotic syndrome
• Lymphatic obstruction (chylous)

Question 6

SAAG > 11.1 g/L (Transudate) (3)

Answer 6

• Portal hypertension (cirrhosis)
• Heart failure
• Hepatic outflow obstruction (Budd-chiari syndrome, venocclusive disease)

Question 7

Ascitic fluid total protein

Answer 7

May be used to differentiate causes of ascites, esp. if ascitic albumin or serum albumin is not known

Question 8

Ascitic T. Protein < 25

Answer 8

• Portal hypertension (cirrhosis)
• Nephrotic syndrome

Question 9

Ascitic T. Protein > 25

Answer 9

Heart failure

Question 10

Ascites from cirrhosis

Answer 10

SAAG > 11.1g/L and Ascitic T. Protein < 25

Question 11

Spontaneous bacterial peritonitis (SBP) (5)

Answer 11

• Occurs in 8% of cirrhotic patients with ascites and has a mortality rate of 10-15%
• Most common infecting organism is E.coli
• Suspect diagnosis in any patient with cirrhotic ascites who deteriorates
• Empirical antibiotic therapy with a third-generation cephalosporin (IV cefotaxime) is started if the ascitic fluid neutrophil count is >= 250 cells/mm3
• Antibiotic prophylaxis with oral norfloxacin is indicated in after one episode or in patients at high risk (ascites protein <10 g/dL or severe liver disease)
• SBP is also an indication for referral to a liver transplant center

Question 12

Management of ascites due to portal hypertension/cirrhosis (4)

Answer 12

1- Stepwise diuretic approach:
- Dietary sodium restriction 40 mmol/day and oral spironolactone daily
- Furosemide daily is added if response is poor
- Aim of treatment: to lose about 0.5kg of body weight each day
- Too rapid diuresis causes intravascular volume depletion and hypokalemia which can precipitate encephalopathy
- A rising creatinine level or hyponatremia indicates inadequate renal perfusion and the need for temporary cessation of diuretic therapy
2- Paracentesis:
- In those with tense ascites or resistant to standard medical therapy
- Removed over several hours providing rapid symptom relief
- IV infusion of albumin administered immediately after paracentesis increases the circulating volume and prevents re-accumulation
3- TIPS is occasionally used for resistant/refractory ascites
4- Note: both diuretics and TIPS predispose to encephalopathy