Flashcards in Diagnosis of effusions Deck (43):
What is an effusion?
increased amount of fluid (abdominal or thoracic cavity), not a disease but a sign of a pathologic process, may be the only cause of clinical signs
Why analyse an effusion?
-differentiate fluid types --> further diagnostics and management
-identify fluid types with a more specific aetiology
Into which tubes do you collect fluid?
-into EDTA for counts, cytology and protein
-into serum/plain tube for biochemistry or culture
What are the 3 most important things looked at on fluid analysis?
-total nucleated cell count (TNCC)
-cell identification and morphology
What else can be looked at?
-enzymes (amylase, lipase)
-urea and creatinine
-cholesterol and Tg
Describe normal fluid (volume, colour, protein, nucleated cell count, other cells)
clear, straw colour
total protein: 25-30g/L
nucleated cell count <3*10^9/L
-mesothelial cells and macrophages
4 factors regulating fluid movement
-collod osmotic pressure (albumin)
-capillary wall permeability
How are transfusions classified? 3
TNCC, total protein and cell morphology/size
3 types of effusion
transudate, modified transudate (less so), exudate.
Describe transudate (colour, protein, nucleated cell count, other cells)
low protein and cellularity
S.G. < 25g/L
TNCC <0.5 * 10^9/L
mesothelial cells, macrophages, low numbers of non-degenerate neutrophils
Causes - transudates
-decreased colloid osmotic pressure - hypoalbuminaemia (classic simplest theory but rarely occurs as often alterations in hydrostatic pressure too). This may occur secondary to glomerular disease, hepatic disease or GI loss (e.g. PLE). Most animals with abdominal transudates have albumin in range of 15-25g/L so other factors are involved.
What exudate do hepatic cirrhosis and portal hypertension cause?
Describe pathogenesis of transudate formation secondary to hepatic fibrosis/cirrhosis
Prolonged portal hypertension and formation of secondary collateral circulation --> local production of local vasodilators (NO), leads to splanchnic vasodilation and decreased effective BF, compounded by renal secretion of sodium via RAAS and generalised hypertension --> expansion of plasma volume and leakage of low protein lymph from the intestines
Desribe modified transudate (colour, protein, nucleated cell count, other cells)
yellow to serosanguinois, cloudy
TNCC 0.3-5.5 * 10^9/L (up to 7*)
SG 1.018 to 1.030
protein variable 25-50g/L
mesothelial cells, macrophages, non-degenerate neutrophils, small lymphocytes
Causes of modified transudates? 3
lymphatic obstruction (neoplasia)
Explain pathogenesis of how cardiac diseae leads to modified transudate formation
chronic passive congestion --> increased hydrostatis pressure, especially in hepatic sinuosids, leakage of protein rich lymph from liver, Na and fluid retention.
Desrcibe exudate (colour, protein, nucleated cell count, other cells)
high TNCC and protein
turbid -red, yellow, white
SG > 1.018
total protein >30g/L
TNCC >3.0 *10^9/L
neutrophils (Degenerate or not), macrophages, (lymphocytes and eosinophils)
Causes - exudates 3
-inflammation of pleural/abdominal cavities or their linings (septic vs non-septic)
-long-standing modified transudate
Distinguish non-septic exudate from a septic exudate
NON-SEPTIC: non-degenerate neutrophils, no bacteria, FIP
SEPTIC: degenerate neutrophils and intracellular bacteira
Describe the fluid found in FIP
TNCC variable (0.2-23 * 10^9/L)
non-degenerate neutrophils and macrophages
high protein (35-80g/L)
albumin: globulin >0.81 on fluid - highly correlated
positive coronavirus (higher titres more suggestive in dry FIP (>640), may be 0->1280 with wet
alpha-1-acid glycoprotein (APP) elevation >1500microg/mL
FLUID MAY BE CLASSIFIED AS MODIFIED EXUDATE OR TRANSUDATE DEPENDING ON TNCC
Describe a healthy neutrophil
-dense chromatin fibres
Describe a haemorrhagic effusion
total protein >30g/L
TNCC 1.5-10*10^9/L (ccompare with peripheral blood)
cells present (WBC from peripheral blood, includes neutrophils), and macrophages
Types of haemorrhage and how to distinguish them - 3
IATROGENIC OR ONGOIN (eryhrocytes and platelet clumps)
ACUTE HAEMORRHAGE (erythrophagia)
CHRONIC (siderophages, haematoidin)
What might platelets in you fluid mean? 3
-you sampled actual blood
-animal still haemorrhaging (rare)
Describe a chylous effusion (colour, protein, nucleated cell count, other cells)
protein variable >30g/L
ACUTE - small lymphocytes, macrophages, mature neutrophils, variable
CHRONIC: mixed population with increased neutrophils and macrophages but decreased lymphocyte % (although still many)
Describe levels of Tg in chylous effusion fluid
Tg in fluid greater than in serum (and cholesterol lower)
What is a 'cream top'?
the chylomicrons that form on the top of a chylous effusion if it is refridgerated
What can you use to stain lipid droplets?
Describe other features of a chylous effusion
-cholesterol:tg ratio of 100mg/dL (1.13mmol/L)
What are mesothelial cells? Why are they important?
Normal lining cells of the abdominal and thoracic cavities/ Show 'reactive change' with inflammation or effusions that can cause them to be confused with neoplastic cells. Requires biopsy and histopathology to confirm a diagnosis of a neoplasm.
Describe the appearance of mesothelial cells
they have a corona/cytoplasmic bleb that looks a bit like cilia. can have multiple nuclei and other features that make cells look like tumours (although they're not!)
Describe some ectopic sources of fluid
Urine --> uroabdomen
Bile - bile peritonitis
All of these can produce variable amounts of effusion and inflammation. TNCC and protein levels will vary.
Describe uroabdomen fluid - classification
transudate/modified transudate (if chonric)
Describe bile peritonitis fluid - classification
green colour, modified transudate/exudate
Describe pancreatitis fluid - classification
Describe biochemistry ratios of creatinine, lipase and bilirubin in fluid vs plasma
CREATININE - much higher in urine normally than plasma
BILIRUBIN (bile duct/gall bladder rupture) - much higher in blood normally. If higher in cavity fluid than in blood, then bilirubin has leaked.
Describe equine peritoneal fluid - volume
Normally find low volume in equine abdomen (100-300ml) so can collect 3-5ml from a normal horse. Increased volume = effusion
Describe equine peritoneal fluid (colour, protein, nucleated cell count, other cells)
pale yellow, clear
TNCC 0.5-9.0 * 10^9/L (usually < 4.0*)
specific gravity 1.000 - 1.010
Approximately 50% macrophages and 50% non-degenerate neutrophils
roughly equivalent to a modified transudate
Describe equine peritoneal fluid - NON-SEPTIC EXUDATE (colour, protein, nucleated cell count, other cells)
amber slightly turbid fluid
Describe equine peritoneal fluid - SEPTIC EXUDATE (colour, protein, nucleated cell count, other cells)
yellow, brown, turbid
TNCC > 10*10^9/L
protein > 34g/L
degenerate neutrophils, bacteria
loog for plant material = rupture of perforation of gut wall
What is enterocentesis?
tap into gut
What might you see on enterocentesis?
plant material, protozoa and bacteria (mixed population), very few cells