Ascites

Question 1

What clinical signs are associated with ascites?

Answer 1

Dependent on underlying cause
- The obvious – abdominal distension
* Some discomfort
* Dyspnoea – either from pressure on diaphragm, or if also have pleural effusion
* Lethargy
* O’s may report weight gain, difficulty getting up/lying down
* Other signs depending on underlying cause (eg V/D – liver disease, coughing/syncope – CHF etc)

Question 2

What are differential diagnoses for ascites?

Answer 2

• Organomegaly (eg splenomegaly, hepatomegaly)
• Abdominal mass
• Pregnancy
• Bladder distension
• Obesity
• Gastric distension
  All these cause abdominal distension without effusion

Question 3

How can we identify ascites?

Answer 3

• history
• clinical exam
• ballottement
• ultrasound

Question 4

What should we do if we see fluid on a scan?

Answer 4

abdominocentesis!!

Question 5

How can we identify the fluid type?

Answer 5

• Gross appearance (and smell!) – eg sceptic – opaque and foul smelling
• Cellularity – number and type – good quality smears
• Protein content
• Easy to do – refractometer, microscope
• If less urgent, send to lab

Question 6

What pathophysiology is associated with protein poor transudate? What are differential diagnoses? How can it be investigated?

Answer 6

Pathophysiology:
* Altered fluid dynamics
* Hypoalbuminaemia (<15g/l, and often <10g/1) – so marked decrease in albumin
* Decrease in plasma colloid oncotic pressure

Differential diagnoses:
* Protein-losing nephropathy
* Hepatic failure (due to either hypoalbuminaemia or pre-hepatic portal hypertension, or a combination
* Protein-losing enteropathy

Investigations:
* Biochemistry = key
* Urinalysis, ultrasound

Question 7

What pathophysiology is associated with protein rich transudate? What are differential diagnoses? How can it be investigated?

Answer 7

Pathophysiology:
* Increased hydraulic pressure within blood and/or lymphatic circulation – usually lungs or liver
* Protein leaks from permeable capillaries, ascites develops when resorptive capacity of regional lymphatics is overwhelmed.
* TP is the important characteristic – over time, transudates will irritate the mesothelium, leading to inflammation, and increased TNCC

Differential diagnoses:
* Cardiovascular disease
* Chronic liver disease – post-hepatic portal hypertension
* Neoplasia
* Thrombosis

Investigations:
* Ultrasound
* Radiography (thoracic)
* Biochemistry

Question 8

What are the 2 types of exudates? What pathophysiology is associated?

Answer 8

Can be septic or non-septic

• Inflammatory process – chemotactants and vasoactive substances attract inflammatory cells, and cause increased vascular permeability
• High TNCC – neutrophils and other phagocytic/inflammatory cells.

If septic – can be bacteria, fungi or mycoplasma

Question 9

What differential diagnoses are possible for septic exudate? How can you investigate it?

Answer 9

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

**Investigations **
* Abdominocentesis
* Appearance/smell of fluid
* Cytology – numerous degenerate neutrophils +/- intracellular bacteria
* Culture and sensitivity
* Lactate, glucose

Question 10

What differential diagnoses are possible for non-septic exudate? How can you investigate it?

Answer 10

Differential diagnoses:
* Neoplasia
* Uroperitoneum
* Bile peritonitis
* FIP

Investigations:
* Abdominocentesis
* Appearance of fluid
* Cytology – non-degenerate neutrophils, absence of bacteria
* Fluid analysis – high urea, creatinine and potassium in fluid if uroperitoneum, green-gold material if bile peritonitis
* Biochemistry (especially for uroperitoneum)
* Ultrasound

Question 11

What pathophysiology is associated with lymphatic compromise effusion? What are differential diagnoses? What investigations can we undertake?

Answer 11

Rare (more commonly chylothorax)
Chylous or non-chylous
Obstruction or destruction of lymphatics
Leakage of lymph and lipids

Differential diagnoses
* Cardiac disease
* Hepatic disease
* Neoplasia
* Steatitis

Investigations
* Appearance – may look ‘milky’
* Cytology - numerous small lymphocytes, over time, irritation leads to increase in neutrophils and macrophages
* Fluid analysis – triglyceride higher than serum, cholesterol lower
* Ultrasound
* Biochemistry

Question 12

What differentials are possible for haemorrhagic effusions? What investigations are possible?

Answer 12

Differential diagnoses:
* Surgical and non-surgical trauma
* Haemostatic defects
* Neoplasia

Investigations:
* PCV & TP of fluid
* Presence of platelets
* Cytology
* Ultrasound