Introduction to pathology

Question 1

To describe a lesion, include:

Answer 1

1. Location
2. Number/extent
3. Demarcation
4. Distribution
5. Colour
6. Size
7. Shape
8. Consistency and texture
9. Any particular sounds or smells

Question 2

Differentiate clinical diagnosis from clinical pathological diagnosis

Answer 2

• Clinical diagnosis: based on case history, clinical signs and physical exam. Example: canine parvovirus infection
• Clinical pathologic diagnosis: based on changes observed in chemistry of fluids and haematology. Example: neutropenia

Question 3

Autolysis

Answer 3

changes due to self-digestion, caused by intracellular enzymes leaking through cell membranes

Question 4

Putrefaction

Answer 4

colour and textural changes, gas production, and odours that are caused by post-mortem bacterial metabolism and dissolution of host tissues (post-mortem decomposition)

Question 5

Rigor mortis

Answer 5

contraction of the muscles occurring after death.

This is due to depletion of ATP and glycogen.

This commences 1-6hrs after death and persists for 1-2 days.

Question 6

Livor mortis

Answer 6

gravitational pooling of blood to the downside of the animal. Can be seen on the surface in light-skinned animals and within organs e.g. the lungs.

Question 7

Answer 7

Livor mortis

Question 8

Post-mortem clotting

Answer 8

Clotting that occurs as it would in life, but clots do not adhere to the vessel walls.

This is especially evident in the heart and great vessels, within several hours after death.

Question 9

Haemoglobin imbibition

Answer 9

Red staining of tissue that occurs once integrity of the blood vessel is lost and haemoglobin is released by lysed erythrocytes.

Question 10

Answer 10

Haemoglobin imbibition

Question 11

How does haemoglobin imbibition differ from liver mortis?

Answer 11

• Haemoglobin imbibition = the erythrocytes have been lysed

Question 12

Bile imbibition

Answer 12

Bile in the gallbladder stains adjacent tissue yellowish/greenish/brown.

Question 13

Answer 13

Bile imbibition

Question 14

Pseudomelanosis

Answer 14

Blue-green discolouration of tissue by iron sulphide (FeS).

Formed when hydrogen sulphide generated by putrefactive bacteria and iron from haemoglobin from lysed erythrocytes interacts.

Staining can resemble melanin, hence the name.

Question 15

Pathogenesis

Answer 15

the process by which a disease or disorder develops

Question 16

Aetiology

Answer 16

Cause or manner of causation of a disease.

Question 17

Azotemia is

a) a clinical diagnosis
b) a morphologic diagnosis
c) an aetiologic diagonsis
d) a clinical pathologic diagnosis

Answer 17

Azotemia is

a) a clinical diagnosis
b) a morphologic diagnosis
c) an aetiologic diagonsis

d) a clinical pathologic diagnosis

Question 18

True/false: thrombosis is a normal finding.

Answer 18

False.

Thrombosis is a pathologic process in response to injury.

It is an interaction between the blood coagulation system and platelets to form a clot in a vascular system.

It relies on this triad:

Question 19

Which of the following is the same regardless of species or organ system?

a) anatomic pathology
b) systemic pathology
c) pathology
d) general pathology

Answer 19

a) anatomic pathology
b) systemic pathology
c) pathology
d) general pathology

Question 20

Which of the following is a function of anatomic pathology?

a) blood smear
b) BUN
c) FNA
d) biopsy

Answer 20

a) blood smear
b) BUN
c) FNA

d) biopsy

Question 21

Answer 21

A chicken fat clot

Caused by the separation of red and white blood cells

Question 22

Pathology

Answer 22

study of disease; the structural, biochemical and functional changes in cells, tissues, and organs that underlie disease

Question 23

General pathology

Answer 23

Basic responses of cells and tissues to noxious stimuli/insults and injuries irrespective of the organ/organ systems, species etc. of animal involved

Question 24

Anatomic pathology

Answer 24

examination of tissues taken during life (biopsy) or death (necropsy). This encompasses histopathology.

Question 25

Clinical pathology

Answer 25

examination of blood and other body fluids as well as cytology (taken during life)

Question 26

Classify the following as lesions or artefacts:

1. Livor mortis
2. Haemoglobin/bile imbibition
3. Pseudomelanosis
4. Autolysis/putrefaction

Answer 26

These are all artefacts

Question 27

What does the following liver show?

Answer 27

Autolysis/putrefaction

Question 28

How do you write a morphologic diagnosis? (European convention)

Answer 28

1. Organ
2. Severity (mild/moderate/severe)
3. Duration (peracute/acute/subacute/chronic/chronic-active)
4. Descriptors
5. Diagnosis

If it’s a neoplasia, then:

1. Organ
2. Neoplasia

Question 29

What is your morphologic diagnosis?

Answer 29

Lungs: pneumonia, suppurative, multifocal, severe, acute.

Question 30

What is your morphologic description?

Answer 30

There was a raised, well-demarcated, dark red, mottled, soft and irregularly shaped mass measuring X by X cm on the outer wall of the right ventricle, just below the right auricular appendage. Upon incision, the mass oozed a small amount of blood.

Question 31

What is your morphologic diagnosis?

Answer 31

Heart: right ventricle, haemangiosarcoma.

Question 32

What is your morphologic diagnosis?

Answer 32

Whole body (likely that if mm and pinna are yellow, so is everywhere else): icterus, diffused, severe, subacute.

Question 33

Describe this lesion and provide a morphologic diagnosis

Answer 33

Stomach is diffusely distended, gas-filled, and diffusely dark red.

Stomach: necrosis, diffuse, severe and acute with dilation.

Question 34

What are some reasons why you might perform a post-mortem exam?

Answer 34

• To determine cause of death
• Outbreak investigation
• Forensic investigation (abuse/negligence)
• Zoonoses
• Contribute to knowledge e.g. paper publication
• Assess treatment effects (lab setting)