10.6.1: Ascites

Question 1

Clinical signs suggestive of ascites

Answer 1

• (Depends on underlying cause):
• Discomfort
• Dyspnoea (pressure on diaphragm/concurrent pleural effusion)
• Lethargy
• O may describe: weight gain, difficulty getting up/lying down
• Other signs: V+/D+, coughing, syncope

Question 2

Causes of abdominal distension without effusion (ddx for ascites)

Answer 2

• Organomegaly
• Abdominal mass
• Pregnancy
• Bladder distension
• Obesity
• Gastric distension

Question 3

Types of fluids seen in ascites

Answer 3

• Protein-poor transudate
• Protein-rich transudate
• Exudate

Question 4

Differential diagnoses for protein-poor transudate

Answer 4

• Protein-losing enteropathy
• Hepatic failure
• Protein-losing nephropathy

Question 5

Describe the pathophysiology of ascites with protein-poor transudate

Answer 5

• There are altered fluid dynamics
• May be due to marked decrease in albumin
• There is decreased plasma colloid oncotic pressure for fluid leaks out

Question 6

Key feature of exudate

Answer 6

High TNCC

Question 7

Differential diagnoses for ascites with protein-rich transudate

Answer 7

• Cardiovascular disease
• Chronic liver disease e.g. post-hepatic portal hypertension
• Neoplasia
• Thrombosis

Question 8

Describe the pathophysiology of protein-rich transudate

Answer 8

• Increased hydrostatic pressure within blood and/or lymphatics (usually lungs or liver)
• Protein leaks from permeable capillaries.
• Ascites develops when resorptive capacity of regional lymphatics is overwhelmed

Question 9

Differential diagnoses for septic exudate

Answer 9

• Penetrating wound
• Surgical complication
• Rupture of infected lesion
• Bacteraemia (rare)

Question 10

Describe the pathophysiology of ascites with exudate

Answer 10

• Inflammatory process (e.g. chemotactants and vasoactive substances) attract inflammatory cells and cause increased vascular permeability
• High TNCC are neutrophils/other inflammatory cells
• Can be septic or non-septic

Question 11

Differential diagnoses for ascites with non-septic exudate

Answer 11

• Neoplasia
• Uroperitoneum
• Bile peritonitis
• FIP

Question 12

Differential diagnoses for ascites for haemorrhagic effusion

Answer 12

• Surgical and non-surgical trauma
• Haemostatic defects
• Neoplasia

Question 13

Differential diagnoses for ascites with lymphatic compromised effusion (chylous or non-chylous)

Answer 13

• Cardiac disease
• Hepatic disease
• Neoplasia
• Steatitis

Question 14

How would you investigate an ascites with suspected protein-poor transudate?

Answer 14

• Biochemistry to assess albumin levels, renal parameters
• Urinalysis to assess renal health
• Ultrasound to locate fluid, assess abdo organs e.g. intestines, kidneys, liver

Question 15

How would you investigate ascites with a suspected protein-rich transudate?

Answer 15

• Ultrasound
• Radiography (thoracic)
• Biochemistry
• Could assess total protein with refractometer

Question 16

How would you investigate ascites with a septic exudate?

Answer 16

• Abdominocentesis and assess appearance/smell of fluid
• Cytology: observe numerous degenerate neutrophils ± intracellular bacteria
• Culture and sensitivity
• Assess lactate and glucose of exudate (compare to blood)

Question 17

How would you investigate ascites with a suspected non-septic exudate?

Answer 17

• Abdominocentesis and appearance of fluid; green-gold material if bile peritonitis
• Cytology: non-degenerate neutrophils, no bacteria presence
• Biochemistry of exudate: High urea, creatinine, potassium if uroperitoneum
• Ultrasound for location/potential cause of effusion e.g. ruptured gallbladder

Question 18

Neoplasia can produce a transudate/exudate/chylous/haemorrhagic effusion?

Answer 18

All of the above.
Neoplasias have variable characteristics and can cause a number of different effusions by different mechanisms