Introduction, Necropsy and Morphological Diagnosis Flashcards
What is pathology?
Scientific study and diagnosis of disease which defines aetiology, developments, processes and consequences
What do the following words mean: Aetiology, Pathogenesis?
Aetiology- causes of disease
Pathogenesis- developments of a disease
What are the 5 point summaries of the key findings with morphological diagnosis?
1) Severity- mild, moderate
2) Duration-actue, subacute
3) Distribution- focal, multifocal
4) Process- necrotising, fibrinous
5) Diagnosis
What are the 5 components to describing inflammation?
a) degree
b) duration
c) distribution
d) type of inflammation/other modifier
e) organ-itis
e. g severe chronic diffuse purulent laryngitis
Generally how long does the classification of inflammation duration last?
Peracute- minutes to hours
Acute- hours to days
Subacute- serveral days to many
Chronic- many days to weeks, months
What do the following suffixs mean?
itis
osis
opathy
itis- inflammation
osis- non-inflammatory lesion which results in tissue damage
opathy- problem or lesion in an organ but pathogenesis is not clear
How is a gross description formed?
think pathology practicals
Location
Distribution
Size
Shape
Colour
Consistency
What are the different causes of abnormal post-mortems?
Pathological
Agonal
PM change
Euthanasia effect
What are agonal changes?
Develop immediatley before death during cardiovascular changes
What are some examples of agonoal changes?
Passive congestion
Pulmonary oedema
Pulmonary emphysema
Stomach contents within oesophagus
Haemorrhage
Intestinal intussusception
Why does passive congestion and pulmonary oedema occur as an agonal change?
Passive congestion- CV output failure- reduced venous returns to heart
Pulmonary oedema- increasing intravascular pressure due to agonal impairment of venous blood return (fluid leaks out of pulmonary capillaries)
Why does pulmonary emphysema and intestinal intussuseption occur as an agonal change?
Pulmonary emphysema- excess air- due to laboured breathing during agonal period, passive exhaling doesn’t clea same volume of air so residual remains in alveolar space
What are examples of post-moretem changes and what does the change depend on?
Autolysis/growth of bacteria, colour changes, changes in texture, tissue detachment, damage to cadaver
Depends on- tissue of origin, temperature, thickness of fleece/blubber, bacterial flora, time span
What are some euthanasia effects?
Effects induced by barbiturate/pentobarbitone
Crystal formation on serosa/endothelium- usually in thoracic cavity/cardiac chamber
Complete necrosis of parenchyma- lungs and myocardium
What are some common colour PM changes and briefly explain them?
Dark red- hypostatic congestion- gravity draws blood
Diffuse reddish stain- haemoglobin imbibition- Hb released by RBC breakdown
Greenish yellowish- bile staining near gall bladder
Green-black- H2S (enteric bacteria) react with haemoglobin producing sulfmethaemoglobin
Which of these is the odd one out and why?
Can you name each of the reasons for the abnormal PM?
A is the odd one out as it is a euthanasia effect, the rest are post-mortem changes
a) crystal formations from the euthanasia drug
b) hypostatic congestion
c) haemoglobin imbition
d) reaction of H2S bacteria with haemoglobin
e) Bile staining
What changes in texture can occur from PM changes and can you explain them?
Eye- Corneal opacity- reduced ocular turgor
Gas formation- liver, GI tract- bacteria proliferate
Putrefaction- carcasses bloating due to gas formation from bacterial formation
Softening of organs- more noticable in solid organs- depends on concentration of proteolytic enzymes
Rigor mortis- 6-8 hours, depletion of ATP
PM clots- not thrombi- easily removed, red clots, white clots
Drying out- mummification
Why is gas formation and putrefaction enhanced in carcasses?
What textural change can be used to estimate PM interval?
An increase in speed of the autolytic processes
Changes in texture of the eye- corneal opacity, reduced ocular turgor
What changes in tissue detachment can occur in PM?
Mucosa detachment
Epilation of hair
What can cause cadaver damage?
Handling artefacts
Scavenging by wild animals
Freezing/thawing artefacts- diffuse red/pink colour
How can you minimise PM changes?
Cool carcass immediatley after death and avoid freezing
Can you explain this PM change?
What is a morphological diagnosis?
In a unique sentence, a summary of all changes oberved and their interpretation
How should you describe a gross photo?
Identify the organ
Identify the anatomical sub-location
Identify the distribution of lesions
Take notes on the size of lesions
Describe shape and contours of lesion
Describe consistency
What are the different words for describing distribution of lesions?
Multifocal- lots of seperate lesions
Multifocal to coalesing- lots of seperate lesions some joining together
Focally/focally extensive- like wildfire spreading (in one place)
Disseminated- lots
Diffuse- everywhere
What are different consistencies found?
Semi-fluid
Soft
Hard
What are some examples of raised and depressed lesions?
Raised:
Abscesses
Granulomas
Primary/metastatic tumours
Depressed- necrosis, fluid filled lesions artefactually emptied
What are the three types of slides?
Glass
Microphotographs
Virtual slides
How should you approach describing a slide?
Start from a low power of magnification
Know the tissue size
Locate the tissue
Locate the region of interest
Anticipate distribution
What does heterogenous and homogenous cells mean?
Heterogenous- necrosis/degeneration, inflammation, visible aetiology?
Homogenous- neoplasia- round, carcinoma, sarcoma
What are the 5 steps to producing a morphological diagnosis from a slide?
1) recognise the tissue
2) locate the area with variation from normal anatomy
3) Decide if monographic or pleomorphic
4) go ahead with description
5) produce your morphological diagnosis
How do you create a morphological diagnosis?
- animal species
- organ
- severity
- duration
- distribution
- process type
- with…
Which marker is used to identify histogenesis of neoplastic mass?
Cytokeratin
Factor VIII
Vimentin
C-Kit
Factor VIII
Cytokeratin- marker for epithelial and glandular cells
What does granulomatous mean?
A tiny cluster of WBC and other tissues
