Ascites

Question 1

What is ascites?

Answer 1

An accumulation of free fluid within the peritoneal cavity that leads to abdominal distension.

Question 2

What are the 2 types of ascites?

Answer 2

1. Transudative - high SAAG
2. Exudative - low SAAG
   = This classification is based on the amount of protein found in the fluid.

Question 3

What is SAAG?

Answer 3

Serum Ascites Albumin Gradient (SAAG).

Based on the amount of albumin in the ascitic fluid compared to the serum albumin (albumin measured in the blood).

Question 4

Give 4 pathophysiological causes of ascites and an example for each.

Answer 4

1. Local inflammation e.g. peritonitis.
2. Leaky vessels e.g. imbalance between hydrostatic and oncotic pressures.
3. Low flow e.g. cirrhosis, thrombosis, cardiac failure.
4. Low protein e.g. hypoalbuminaemia.

Question 5

Give 3 risk factors for ascites.

Answer 5

1. High sodium diet
2. Hepatocellular carcinoma
3. Splanchnic vein thrombosis resulting in portal hypertension

Question 6

Give 3 causes of transudate ascites.

Answer 6

1. Portal hypertension (cirrhosis)
2. Hepatic outflow obstruction
3. Budd-Chiari syndrome
4. Cardiac failure
5. Tricuspid regurgitation
6. Constrictive pericarditis
7. Meig’s syndrome

Question 7

What can cause transudative ascites?

Answer 7

Increased venous pressure due to cirrhosis, cardiac failure or hypoalbuminaemia.

Question 8

What can cause exudative ascites?

Answer 8

Increased vascular permeability secondary to infection; inflammation (peritonitis) or malignancy.

Question 9

Give 3 causes of exudate ascites.

Answer 9

1. Peritoneal carcinomatosis
2. Peritoneal TB
3. Pancreatitis
4. Nephrotic syndrome
5. Lymphatic obstruction

Question 10

Name the 2 main pathophysiological factors that contribute to the formation of ascites.

Answer 10

1. High portal venous pressure.
2. Low serum albumin.

Question 11

Describe the pathogenesis of ascites.

Answer 11

1. Increased intra-hepatic resistance leads to portal hypertension -> ascites.
2. Systemic vasodilation leads to secretion of RAAS, NAd and ADH -> fluid retention.
3. Low serum albumin also leads to ascites.

Question 12

Give 3 signs of ascites.

Answer 12

1. Flank swelling.
2. Dull to percuss and shifting dullness.
3. Large distended abdomen.

Question 13

Diagnosis of ascites.

Answer 13

1. Physical abdominal examination
   - Presence of fluid is confirmed by demonstrating shifting dullness
2. Diagnostic aspiration of 10-20ml of fluid using ascitic tap for:
   * Raised white cell count - indicative of bacterial peritonitis
   * Gram stain and culture
   * Cytology to find malignancy
   * Amylase to exclude pancreatic ascites
3. Protein measurement of ascitic fluid from ascitic tap:

• Transudate (less bad) - low protein (< 30g/L) - transparent i.e. no/little
  protein:
• Portal hypertension e.g. cirrhosis
• Constrictive pericarditis
• Cardiac failure
• Budd-Chiari syndrome
• Exudate (extremely bad) - high protein (> 30g/L) - exudes protein:
• Malignancy
• Peritonitis
• Pancreatitis
• Peritoneal tuberculosis
• Nephrotic syndrome

Question 14

What would you find on an abdominal examination of a patient with ascites?

Answer 14

SHIFTING DULLNESS.
Fullness in flanks.

Question 15

Describe the physical abdominal examination procedure to check the signs for ascites.

Answer 15

Large distended abdomen - can be observed.

Shifting dullness - classic sign:
Percuss abdomen and observe dullness over fluid versus resonance over air. Ask the patient to roll on to one side, wait a good few seconds for fluid to settle at a new level .
Then, re-percuss on the side and observe the dullness has shifted.

Question 16

What tests would you run on ascitic fluid once aspirated?

Answer 16

• Raised WCC - indicative of bacterial peritonitis
• Gram stain and culture
• Cytology to find malignancy
• Amylase to exclude pancreatic ascites

Question 17

You do an ascitic in someone with ascites. The neutrophil count comes back as - Neutrophils > 250/mm3. What is the likely cause of the raised neutrophils?

Answer 17

Spontaneous bacterial peritonitis.

Question 18

Treatment of ascites.

Answer 18

1. Bed rest
2. Fluid and salt restriction - low sodium diet
3. Spironolactone ± furosemide
4. Paracentesis (drainage - ascitic tap or ascitic drain)
5. Prophylactic antibiotics against spontaneous bacterial peritonitis (ciprofloxacin or norfloxacin) in patients with less than 15g/litre of protein in the ascitic fluid
6. Consider TIPS procedure in refractory ascites
7. Consider transplantation in refractory ascites

Question 19

A man has his ascites drained and is advised to restrict his diet. Which non-hormonal substance will promote re-accumulation of the ascites?

Answer 19

Salt.

Question 20

What investigation is it important to do in someone with chronic liver disease and ascites? Explain why it is important.

Answer 20

It is important to do an ascitic tap so you can rule out spontaneous bacterial peritonitis as soon as possible.