Ascites Flashcards
Clinical signs
Dependent on underlying cause
- abdominal distension
- some discomfort
- dyspnea: either from pressure on diaphragm, or if also have pleural effusion
- lethargy
- O may report weight gain, difficult getting up / lying down
- other signs dependent on underling case (eg. v/d - liver dz, coughing/syncope - CHF)
Differential diagnoses
- organomegaly (splenomegaly, hepatomegaly)
- abdominal mass
- pregnancy
- bladder distension
- obesity
- gastric distension
How to identify ascites
- history (past & recent)
- CE
- ballottement
- US
Sampling the fluid
- if you see fluid on US, sample it
- abdominocentesis / peritoneal tap
How do we identify the fluid type?
Gross appearance & smell
- e.g. septic -> opaque and foul smelling
Cellularity
- number and type from good quality smears
Protein content
Easy to do with refractometer, microscope
If less urgent can send to lab
Types of fluid
- transudate / protein-poor
- modified transudate / protein-rich
- exudate
Fluid types: Transudate / protein-poor
- appearance
- TP (g/l)
- TNCC (x10^9/l)
- cytology
Appearance
- clear, colourless or pale straw colour
TP (g/l)
- <20 (often <15)
TNCC (x10^9/l)
- <1.5
Cytology
- neutrophils and macrophages with some mesothelial cells
Fluid types: Modified transudate / protein-rich
- appearance
- TP (g/l)
- TNCC (x10^9/l)
- cytology
Appearance
- often yellow, blood tinged, turbid
TP (g/l)
- usually >20
TNCC (x10^9/l)
- <5
Cytology
- macrophages and mesothelial cells, increasing number of neutrophils and small lymphocytes
Fluid types: Exudate
- TP (g/l)
- TNCC (x10^9/l)
- cytology
Appearance
- typically turbid, various colours
TP (g/l)
- >20
TNCC (x10^9/l)
- >5
Cytology
- neutrophils, or neutrophils and macrophages
Transudate - pathophysiology
- altered fluid dynamics
- hypoalbuminaemia (<15g/l, and often <10g/l), so marked decrease in albumin
- decrease in plasma colloid oncotic pressure
Transudate - ddx
- PLN
- hepatic failure (due to either hypoalbuminaemia or pre-hepatic portal hypertension, or a combination)
- PLE
Transudate - investigations
- biochemistry KEY
- urinalysis (if suspect PLN)
- US (to look at gull walls etc, esp if suspect PLE)
Modified transudate - 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
Modified transudate - ddx
- cardiovascular dz
- chronic liver dz: post-hepatic portal hypertension
- neoplasia
- thrombosis
All have a poor prognosis so need to manage O expectations
Modified transudate - investigations
- US
- Radiography (thoracic)
- biochemistry
Exudate - pathophysiology
- inflammatory process: chemotactants and vasoactive substances attract inflammatory cells, and cause increased vascular permeability
- high TNCC: neutrophils and other phagocytic/inflammatory cells
- can be septic or non-septic
- if septic: can be bacteria, fungi or mycoplasma
Septic exudate - ddx
- penetrating wound
- surgical complication
- rupture of infected lesion
- bacteraemia (rare)
Septic exudate - investigations
- abdominocentesis
- appearance/smell of fluid: cloudy fluid that smells
- cytology: numerous degenerate neutrophils +/- intracellular bacteria
- C&ST
- lactate, glucose
Non-septic exudate - ddx
- neoplasia
- uroperitoneum
- bile peritonitis
- FIP
Non-septic exudate - 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
- biochem (esp for uroperitoneum)
- US
Other effusions: lymphatic compromise - what is it?
- rare (more commonly chylothorax)
- chylous or non-chylous
- obstruction or destruction of lymphatics
- leakage of lymph and lipids
Other effusions: lymphatic compromise - ddx
- cardiac dz
- hepatic dz
- neoplasia
- steatitis
cardiac & hepatic dz can cause obstruction of the lymph vessels
Other effusions: lymphatic compromise - 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
- US
- biochemistry
Steatitis - definition
= inflammation of the fat (uncommon)
