Post Mortem Flashcards
pluck
tongue
thyroids
trachea
oesophagus
lunds
heart
thymus
morphological diagnosis
pathological process
distribution
severity
timescale
organ or tissue
colour
red/dark red/red-black/pink - blood - hyperemia, congestion, haemorrhage, erythrocyte lysis, haemoglobin inbibition
red-black - haemorrhage and necrosis
yellow - icterus
blue-green-black - pseudomelanosis
brown-black - melanosis, melanoma
white-grey-green - necrosis, fibrosis (chronic)
agonal change
normal change around time of death
blood cysts
red lump at mitral valve
incidental
young ruminants
encocardiosis
thickened, cream mitral valve
age related
incidental
age related incidental calcification
multifocal gritty areas in lungs
widespread - renal failure from vitamin D toxicity
paralaphenstrongylus tenuis
multifocal nematodes - brain and eye
incidental in deer
neurologic disease in ruminants
ascarid migration
multifocal white to pale tan foci in liver
incidental unless heavy load
nodular hyperplasia
focal expanded parenchyma of spleen
benign but can rupture
could be hemangiosarcoma, lymphoma or hystiocystic sarcoma
splenic trauma
focally divided parenchyma of spleen
previous trauma - not cause of death
omental adhesions - previous rupture
siderotic plaques
raise cream multifocal gritty plaques on spleen
accumulation of debris from erythrocyte turnover
renal cysts
incidental or pathological depending on signs and how many
animal models of disease
comparing human disease with animal models
spontaneous models - eg NOD mouse (non-obese diabetic) - inbred
induced - chemical or genetic
chemical - streptozotocin given to mice, toxic to pancreatic cells - induces type 1 diabetes
genetic - knock in, knock out, or transgenic - mouse model with upregulated HER2 to model breast cancer development
models for arthrosclerosis
arthrosclerosis = narrowing of vessels, lipid, fibrous and clacium deposits in vessle walls
cause of heart attack in humans
rabbit models -
cholesterol fed
watanabe heritable hyperlipemdemic rabbits
genertically modified rabbits
COVID-19 models
hamsters - naturally susceptible to covid-19
syrian - moderate self limiting disease - respiratory tract inflammation and age dependence
roborovski dwarf - mimics disease in highly suscpetible patients - frequently lethal, diffuse alveolar damage and coagulopathy
duchenne’s muscular dystophy models
progressive muscle wasting, mutations in dystophin gene
mouse - no clinical signs, shorted life span
golden retriever with muscular dystophy - show signs but different signs from humans and a lot of variation between dogs
rabbit - created using cAS9 - clear signs like humans, easier to breed
stages in drug development
show target is similar to disease being studies
investigate pharmacokinetics
investigate toxicity
investigate tolerability - adverse behavioural effects
pharmacodynamic effect in target organ
humanised mouse
immunodeficient mouse grafted with human cells and tissue
SCID mouse -
athymic due to genetic mutation - impaired t and b cell development
models tumour microenvironment and contribution of immune system eradicating tumour cells
surveillance aims
animal health and welfare
human health
environment
international trade
hazard groups of zoonotic disease
1 - unlikely to cause human disease
2 - can cause human disease, may be hazard to employees but unlikely to spread to community - chlamydia abortus, toxoplasma gondii
3 - severe human disease, but there is effective prophylaxis or treatment - TB, anthrax, BSA
4 - severe human disease with no treatment - ebola, herpesvirus B in primates, hendra virus
sample taking at post mortem
serology - antigen detection preferable to antibody, need to know what you’re looking for - maedi visna and CAE
histology/cytology -
10% buffered formalin, <1cm thick, edge of affected tissue, 10x formalin to tissue volume
bacteriology/microbiology -
live bacteria, avoid contamination
charcoal swab, sterile sampling
consider previous antibiotic treatment
selective media - anaerobic vs aerobic
staining
virology -
PCR, virus culture (not usually useful), histo + inclusion bodies + IHC
parasitology -
helminths - worm egg count, worm count from washing abomasum and small intestine contents
ectoparasites - skin scrapings, histopath, gross visualisation
protozoa - PCR (toxoplasma and neospora), histopath (histomonas), scrapings, worm egg counts, floatation, smear
blood borne parasites - PCR - post mortem not test of choice
biochem/toxicology -
histo + stains + IHC
haematology and biochem not useful
glucose - urine
tissue analysis for liver and kidney - toxins
eye fluid analysis - aqueous humour for hypocalcemia, vitreous humour for hypomagnesia
plant poisons - slow acting may show histo effects
samples taken in suspected poisoning
stomach and intestinal contents
liver
kidney
post mortem blood
urine
fat
brain
sudden death organ systems
cardiovascular
respiratory
nervous
