Cytology and fluid analysis Flashcards
what is cytology?
study of disease through evaluation of cells
what are the limitations of cytology?
difficult to achieve final diagnosis on cytology alone
can be non-representative of lesion
often needs to be sent away for analysis
what is cytology very good for analysing?
fluids
bone marrow
round cell tumours
how can cells be collected for cytology?
fine needle biopsy imprints/crapes swabs aspiration of fluid collection of fluid (tracheal wash...)
how are mass/organ slides prepared?
squash preparation
how are biopsy slides prepared?
imprint
how are fluid slides prepared?
smear
what is assessed on low power?
quality, cell preservation, distribution
big things (eggs, larvae, fungi, foreign material…)
assess background and cell types
artefacts
what is looked at on very high power?
characterisation of nuclear and cytoplasmic detail
better identification of microorganisms
what lines the peritoneal, pleural and pericardial cavities?
mesothelium
what creates the fluid that lines the mesothelium?
ultra filtrate of blood (low cells and total protein)
what is an effusion?
accumulation of fluid in a. body cavity
how can effusions be classified?
protein, cell count and cytology
aetiology and composition
what are the two effusions based on protein, cell count and cytology?
transudate
exudate
what forms a transudate effusion?
imbalances of hydrostatic/oncotic pressure
what forms a exudate effusion?
increased vascular permeability due to inflammation
what can cause haemorrhagic effusions?
true cavity haemorrhage
iatrogenic blood contamination
how can iatrogenic haemorrhagic contamination be confirmed?
uniformly bloody on swirling
clot forms
supernatant clear
no erythrophagocytosis
what are the features of a true body cavity haemorrhage?
fluid doesn’t clot
supernatant often haemolysed
erythrophagocytosis
how does a chylous effusion appear?
milky/white
what body cavity is chylous effusion most commonly seen in?
thorax
how can pseudochyle be differentiated from chyle?
pseudochyle has low numbers of triglycerides (white colour from cell debris and cholesterol)
how much protein does low protein transudate effusions have in them?
<25g/L
what colour are transudate effusions?
clear/colourless
what causes low protein transudate effusions?
(hypoalbuminaemia) decreased oncotic pressure due to low serum protein
how much protein does high protein transudate effusions have in them?
> 25g/L
what colour is high protein transudate effusions?
colourless to amber to pink
what causes high protein transudate effusions?
increased hydrostatic pressure (congestive heart failure, thrombi, neoplasm)
what is another name for high protein transudates?
modified transudates
how do exudate effusions appear?
turbid
yellow/brown/bloody
what is the main cell in exudates?
neutrophils (inflammation)
what are the two forms of exudate?
septic
non-septic
what are septic exudates classified by?
intracellular organisms (not always present) degenerate neutrophils
what are non-septic exudates classified by?
non-degenerate neutrophils
what can cause septic exudates?
penetrating wound
foreign bodies
GI perforation/ischeamia
haematogenous route
what can cause non-septic exudates?
ruptured gall bladder rupture urinary bladder necrotic tumour pancreatitis FIP
what are the indications for arthrocentesis?
joint disease of unknown aetiology diseases of multiple joint suspected infective arthritis pyrexia of unknown origin monitoring therapeutic response
what colour is normal synovial fluid?
clear/pale yellow
how do synovial fluid in the presence of inflammation look?
yellow turbid
