Intro to Pathology

Question 1

Disease

Answer 1

Any harmful interruption of function of any part/organ/system of the body that is manifested by a characteristic set of symptoms and clinical signs

Question 2

Pathology

Answer 2

The study of disease

Question 3

General Pathology

Answer 3

○ Basic responses of cells and tissues to insults and injuries
○ Irrespective of the organs, systems or species of animal involved

Question 4

Systemic Pathology

Answer 4

○ Pathology of organ systems
○ Alterations in specialised organs and tissues

Question 5

Anatomic Pathology

Answer 5

○ Examination of tissues taken during life (biopsy) or after death (autopsy, necropsy)
○ Examines nature and extent of disease process
○ Gross/macroscopic pathology

Question 6

Clinical Pathology

Answer 6

○ Examination of blood and other bodily fluids and cells
○ Cytology is included in this
Includes Microscopic pathology

Question 7

Aetiology

Answer 7

What used the disease?

Question 8

Pathogenesis

Answer 8

How did the disease develop?

Question 9

Molecular and morphologic changes

Answer 9

What are the biochemical and structural alterations in cells and organs?

Question 10

Clinical Manifestation

Answer 10

What are the symptoms and signs of molecular and morphologic changes?

Question 11

5 Major Pathologic Processes

Answer 11

Inflammation
Healing
Thrombosis
Neoplasia
Metabolic Dysfunction
Necrosis

Question 12

Inflammation

Answer 12

○ Vascular and interstitial changes in response to tissue injury
○ Designed to sequester, dilute and destroy the causal agent
‘-itis’

Question 13

Clinical signs of inflammation

Answer 13

Heat
Redness
Swelling
Pain
Loss of function

Question 14

Healing

Answer 14

○ Repair of injured tissue
○ Involves:
Angiogenesis
Fibrosis
Regeneration
Epithelialisation

Question 15

Angiogenesis

Answer 15

Formation of new blood vessels

Question 16

Fibrosis

Answer 16

Formation of fibrous connective tissue by fibroblasts

Question 17

Regeneration

Answer 17

The capacity to regrow after damage
Not all tissues can regenerate (e.g. cardiac and skeletal muscle)

Question 18

Epithelialisation

Answer 18

Regenerative process that covers defects in injured skin

Question 19

Thrombosis

Answer 19

○ Occurs within vascular lumen
○ Interaction of blood coagulation cascade and platelets to form
○ Thrombus - aggregate of fibrin and platelets
○ Differs from normal clotting
○ Involves Virchow’s triad

Question 20

Virchow’s Triad

Answer 20

Vascular wall damage
Hypercoagulable state
Change in blood flow

Question 21

Neoplasia

Answer 21

○ Any new cellular growth
○ Benign or malignant
○ Basic cellular mutations lead to dysregulations of mitosis and disruption of normal cell boundaries
○ Results in unrestrained cell growth
○ Affects normal tissue through replacement or compression

Question 22

Metabolic Dysfunction

Answer 22

○ Interrupts normal chemical processes necessary to maintain homeostasis
○ Genetic, due to chemical imbalance or organ malfunction

Question 23

Necrosis

Answer 23

○ Death of cells or tissue in a living animal
○ Can be diffuse process in whole organ or partial

Question 24

Methods of pathological examination

Answer 24

Biopsy (LIVING)
Post-mortem/autopsy/necropsy (DEAD)
FNS - Fine needle sampling

Question 25

Pathological description after biopsy

Answer 25

Location Number/extent Demarcation Distribution Colour Size Shape Consistency/texture

Question 26

Example of pathological description of lesion

Answer 26

* On the Forelimb of dog * Singular * Well-demarcated * Focal * Pink to dark red * 3 cm in diameter x 2 cm height * Round, raised * Firm, hairless mass

Question 27

Clinical Diagnosis VS Clinical Pathological Diagnosis VS Morphological Diagnosis

Answer 27

Clinical Diagnosis - based on data from history, clinical signs, physical exam and lab testing Clinical Pathological Diagnosis - based on changes observed in chemistry of fluids, haematology and structure/function of cells Morphological Diagnosis - Based on what is seen

Question 28

Example of Clinical Diagnosis VS Clinical Pathological Diagnosis Vs Morphological Diagnosis

Answer 28

Clinical diagnosis - Canine parvoviral infection Clinical Pathological Diagnosis - Leukopenia (neutropenia, lymphopenia) Morphological Diagnosis - Colitis, necrotic-haemorrhagic, diffuse, severe, acute

Question 29

Lesion Description

Answer 29

Location

Question 30

Morphological Diagnosis

Answer 30

Based on what is seen Macroscopic or microscopic Describes lesion: ○ Severity - mild, moderate, severe ○ Duration - peracute, acute, subacute, chronic ○ Distribution - focal, multifocal, focally extensive, diffuse ○ Location - organ or tissue ○ Nature - (-itis, -osis, -ia)

Question 31

Methods to reach a diagnosis

Answer 31

* Morphology * Molecular biology * Microbiology * Immunology * Genetics * Informatics

Question 32

Post-mortem changes - NOT LESIONS

Answer 32

Autolysis Putrefaction Rigormortis Livor mortis Post-mortem clotting Haemoglobin Imbibition Bile Imbibition Pseudo-melanosis

Question 33

Autolysis

Answer 33

Self-digestion due to ceasing of normal bodily processes

Question 34

Putrefaction

Answer 34

Colour and texture changes Gas production and odours due to bacterial metabolism and dissolution of host tissues

Question 35

Rigor Mortis

Answer 35

Contraction of muscles after death Due to depletion of ATP and glycogen Occurs 1-6 hours after death and persists for 1-2 days

Question 36

Livor Mortis

Answer 36

Gravitational pooling to downside of body Looks a bit like haemorrhage but is not

Question 37

Post-mortem clotting

Answer 37

Different to thrombosis Evident in heart and great vessels several hours after death Does not adhere to vessel walls

Question 38

Haemoglobin imbibition

Answer 38

Differs from livor mortis Red staining due to release of haemoglobin from lysed RBCs

Question 39

Bile imbibition

Answer 39

Green/yellow stain due to release of bile Tissues near gall bladder (e.g. liver)

Question 40

Pseudomelanosis

Answer 40

Blue/green discolouration of tissue due to FeS (iron sulphide) Often mistaken for melanosis Formed by reaction between H2S produced by putrefactive bacteria and iron from haemoglobin from lysed RBCs