Cytology of effusions (Yr 3) Flashcards
what are the features of the serous fluid that facilitates movement in the cavities?
low cellularity
low total protein
(it is an ultrafiltrate)
what are the three things that dictate the amount of fluid in the body cavities?
hydrostatic pressure
oncotic pressure
permeability of vessels
what is the usual cause of transudate effusions?
imbalances in hydrastatic/oncotic pressure
what is the usual cause of exudate effusions?
increased vascular permeability due to inflammation
how can you tell if a effusion sample is iatrogenically contaminated with blood?
initially clear then blood (or vice-versa)
swirling of blood
blood will clot
see platelets under microscope
how can you tell if the blood in the effusion is from true body cavity haemorrhage and not just iatrogenic?
fluid doesn’t clot
supernatant often haemolysed
no platelets and erythrophagocytosis under microscope
how do chyle effusion appear?
milk, white, opaque
what is the usual location of a lesion causing a chylous effusion?
thoracic duct (heart disease, trauma, neoplasia, idiopathic)
what cytology would you expect from chylous effusions?
lots of lymphocytes (it is lymph)
high triglycerides
how can you tell if an effusion is chyle or pseudochyle?
measure triglycerides
(pseudochyle has low triglycerides and is white due to protein, cholesterol or cell debris)
how do transudates appear?
clear and colourless
(TRANSlucent)
what is the cytology findings of transudates?
low protein
low cells (some monocytes and macrophages)
what is the typical cause of transudate effusions?
hypoalbinaemia (protein losing enteropathy, protein losing nephropathy, reduced protein production from liver)
what should be done if you drain a transudate effusion?
measure albumin/creatinine
urinalysis (UPCR)
imaging
look for GI and renal disease
what cytology is found in modified transudates?
more protein than transudates
low cellularity (few more than transudate)
how do modified transudates usually appear?
straw coloured
clear
what is the typical cause of modified transudate effusions?
high intravascular hydrostatic pressure…
CHF, thrombi, neoplasia
what is the findings on cytology of exudates?
high proteins
high cells (lots of neutrophils)
how do exudates appear?
turbid/viscous (lots of cells)
yellow/brown/bloody
what is the main process involved in exudate formation?
inflammation (hence get lots of neutrophils)
what causes the exudate associated with FIP?
vasculitis caused by the virus
how does FIP exudate appear?
yellow stick fluid
what further tests should be done in cases that you suspect FIP due to the exudate sampled?
serology
immunohistochemistry of fluid for coronavirus
(no single test make definitive diagnosis apart from histopathology)
what are the findings on cytology of a bile peritonitis?
neutrophils
macrophages with green pigment
bilirubin concertation in exudate higher than in the plasma
how can you tell from fluid in the peritoneum that there is a bladder rupture?
creatine concentration in the fluid sampled will be higher than in plasma
how does the fluid in the peritoneum due to a ruptured bladder change overtime?
fluid starts as transudate but as the urea irritated the cavity it causes inflammation and changes to an exudate
what are the cytology findings of synovial fluid?
low cells
high protein
