General Pathology Flashcards
What is a lesion?
Any abnormality of tissue that can be seen
What does gross mean in terms of lesions?
Visible with the naked eye
What are histological lesions?
Lesions that can only be seen through a light microscope
What does the term pathognomonic mean?
A lesion that is so distinctive of one disease - This means you are able to make an instant diagnosis
What is aetiology?
The specific cause of the disease e.g. Trauma, bacteria etc.
What tools can be used as a vet to diagnose a clinical problem?
- Histology - Cytology - Clinical Biochem - Haematology
What is cytology?
Smears, Fine needle aspirates, scrapings - Dabbed or scraped onto a glass slide - Helpful only in terms of cells in the lesion itself, not the architecture of the lesion
In basic terms what is disease?
A whole lot of cells that are damaged - cluster of damaged cells can be seen as a lesion
Describe the summary of the pathogenesis of disease…
- Damage to cell membranes, organelles or enzymes - Disease - Lesion (gross or histo) - Diagnostic Investigations
How might the aetiology of disease be determined?
After all diagnostic tests look at extra tests such as: - Cultures - Immunohistochemistry - Molecular analysis
What is somatic death?
Death of the whole body - using somatic in the description is used to distinguish this death from cell degeneration and death
What are post mortem changes?
Normal changes that occur in the body after death - cooling - rigor mortis - blood changes - post mortem degeneration -
Describe post mortem cooling changes…
There is lots of variation in how long it takes for a body to cool down Depends on: - Initial temperature of the body (i.e. whether body was in fever, hot day etc) - Insulation of the body (i.e. wool and fat) - Ambient temperature (i.e. wind
Describe Rigor Mortis…
- All of the body’s Muscle fibres contract (head -> heart -> diaphragm -> limbs) - occurs as body’s ATP runs out (body usually uses ATP to stay relaxed so as the ATP runs out the body then contracts - Muscle fibres then degenerate - Affected by temperature and body condition - Defined order of events - Bendy, hard, bendy
Describe post mortem blood changes…
Hypostatic congestion occurs where blood settles with gravity on the downside of the body - Clotting then occurs, if left long enough in the same position, the blood will also clot with gravity
Why do you have to be careful with hypostatic congestion?
On the lungs it can look like pneumonia - if you remember that this does occur as a post mortem change you should be able to avoid this confusion
Are there differences in clots that happen when alive vs. dead?
Yes - Clots when alive (anti-mortem) are called thombi – Rough and granular looking clots - Clots when dead (post-mortem) are called clots – Smooth, glistening and moulded to shape of blood vessel clot
What are some post mortem degeneration changes…
- Autolysis - Putrefaction - Rate of decay
What is autolysis?
A post mortem degeneration change - Self- dissolving - Own bodies enzymes start to dissolve own body
What is putrefaction?
A post mortem degeneration change - Bacteria - Enzymes from bacteria start to dissolve cells and organs - The bacteria can come from ourselves or from the environment
What is the rate of decay?
A post mortem degeneration change - Influenced by temperature and the presence of bacteria
What post mortem change involving colour can occur with organs that lie alongside each other?
Pseudomelanosis - black staining
What is pseudonecrosis?
Autolysis that happens in patches over an organ
What is haemoglobin imbibition?
The red staining of tissue due to leaching of hemoglobin from autolysed RBCs and blood vessels after death
What is bile imbibition?
The staining of tissues with bile (green-yellow-brown) due to leaching from the bile ducts and gall bladder after death
What is lividity?
???
What is often mistaken for antemortem bloat?
Post mortem the body has no defense against bacteria. They produce gas inside the animal that can’t escape so it looks like the animal has died of bloat
What is this?
A liver with pseudomelanosis
What is this?
A liver with pseudonecrosis
What is this?
Haemoglobin Imbibition
What is this?
Bile imbibition
What is this?
Lividity (hypostasis)
What is this clot?
An antemortem thrombus
What is this clot?
A post mortem Clot
Smooth
Glistening
Along side blood vessel
