All fluid analysis Flashcards
Where is cavitary fluid found?
*Peritoneal, pleural, pericardial cavities
=ultrafiltrate of blood
What does volume of fluid depend on?
*Hydrostatic pressure of blood
*Oncotic pressure of blood
*Permeability of vessels
What is an effusion?
*Accumulation of fluid in body cavity
*rate of fluid formation > rate of fluid removal
How can effusions be classified?
*Transudate = effusion by imbalance of hydrostatic / oncotic pressure
*Exudate = effusion by increased vascular permeability due to inflammation
*Classify by aetiology of composition = Haemorrhagic, chylous, pseudochylous, neoplastic
How can you analyse effusion?
*Appearance = colour, turbidity
*Odour
*Cell counts +TP
*Microscopic examination
*Biochemistry
What causes haemorrhagic effusions?
*True cavity haemorrhage - vessel disruption
*Iatrogenic blood contamination
*Splenic tap
What is iatrogenic contamination?
*Clear then blood or vice-versa
*Swirling of blood - should form clot
*Clear supernatant - can see platelets
What is true body cavity haemorrhage?
*Fluid does not clot - haemolysed supernatant
*Due to RBC degradation in cavity
*No platelets
What are differential diagnosis of true body cavity haemorrhage?
*Bleeding tumours
*Coagulopathy
*Trauma
*Lung lobe torsion
How would you diagnosed haemorrhagic effusions?
*Coagulation profile
*Ultrasound of abdomen for masses
*Look for neoplastic cells on cytology
What is chylous effusions?
*Chylomicron-rich lymph
*Milky fluid
*Protein >25g/l
*High triglyceride content
What are causes of chylous effusions?
*Heart failure
*Trauma / surgery
*Neoplasia
*Idiopathic
What is pseudochyle?
*Looks similar, but not high in triglycerides
What is pure (low protein) transudate?
*Clear, colourless, protein <25g/l
*Few cells - mainly monocytes + macrophages
What causes low protein transudate?
*Decreased oncotic pressure - severe hypoalbuminaemia (protein loss)
*Increased hydrostatic pressure - portal hypertension, over hydration, cardiac failure+ thrombi in major vessels
What is modified (high protein) Transudate?
*Modified - more protein + cells (protein >25g/l)
*Colourless to amber pink
*More neutrophils + erythrocytes than transudate
What causes modified transudate?
*Increased intravascular hydrostatic pressure in liver or lung
- Congestive heart failure
- Thrombi or neoplasia
- Liver disease - portal hypertension
What are exudates?
*Turbid, yellow/brown/bloody
*high cell count + high protein
*mostly neutrophils - inflammation + increased vascular permeability
What is the difference between septic + non-septic exudates?
- Septic = intracellular organisms + degenerate neutrophils
- Non-septic = non-degenerate neutrophils + lower number of hypersegmented neutrophils + pyknotic cells
What causes septic exudates?
- Penetrating wounds
- Foreign bodies
- GI perforations
- Haematogenous route
- LESS commonGall bladder rupture, pancreatitis + rupture of pyometra, abscess in liver/spleen/prostate
What are causes of non-septic exudates?
- Ruptured gall bladder
- Ruptured urinary bladder
- Necrotic tumour
- Pancreatitis
- FIP
What is seen with albumin : globulin ratio in FIP?
*A:G low in FIP
*A:G <0.4 then FIP likely
*A:G >0.8 = NOT FIP
more globulin + less albumin = FIP
What is seen on cytology of bile peritonitis?
*Neutrophils
*Background green pigment
*Macrophages with green pigment
What is seen with ruptured bladder?
- Fluid creatinine > serum creatinine
- Urine = irritant = changes from transudate to exudate
What are the most common neoplastic effusions?
*Lymphoma
*Adenocarcinoma
*Mesothelioma
What are indications for arthrocentesis (joint fluid exam)?
*Joint disease of unknown aetiology
*Diseases in multiple joints
*Suspected infective arthritis
*Pyrexia of unknown origin
*Monitoring therapeutic response
What is seen with synovial fluid colour?
- Normal = clear, pale yellow
- Inflammation = yellow / turbid
- Uniformly bloody = haemarthrosis
- Clear then bloody = contamination
