Introduction to Veterinary Pathology Flashcards
Define pathogenesis
The sequence of events occurring following exposure leading to the development of disease
Define morphological diagnosis
The structural changes seen in cells or tissues that are associated with the disease process
How many times their volume should samples be fixed in buffered formalin
10x their volume
What stain would you use to identify fat
Oil Red O
What stain would you use to identify glycogen
Periodic Acid Shift
What stain would you use to identify fibrous tissue
Mason’s Trichrome
What stain would you use to identify haemosiderin
Peri’s Prussion Blue Reaction
What stain would you use to identify viral proteins
Immunohistochemical stains
Define hypoplasia
Underdeveloped cells
Define aplasia
No cell development
Define agenesis
No cell development because of a lack of primordial tissue
Define hypertrophy
Big cells
Define hyperplasia
Lots of cells
Define metaplasia
The replacement of one cell type with another
Define dysplasia
A change in the size, shape, or organization of cells
List a type of reversible cell injury, the cause, and describe the cell morphology
(Bonus: what is another name for this type of cell injury
Cellular swelling
Result of hypoxia
Vacuoles become very large
(Bonus: hyropic degeneration, or ‘ballooning’ degeneration
What intracellular change is associated with cell necrosis
Think ion balance
Raised intracellular calcium levels
Describe coagulative necrosis of cells
Bonus: Is this an acute or chronic process?
Basic cell outlines are preserved
Bonus: Acute
Describe caseous necrosis of cells
Bonus: Is this an acute or chronic process
There is a friable ‘cheese’ like appearence
Describe liquefactive necrosis of cells
Cavities filled with liquefied debris
Describe fat necrosis of cells
The specific necrosis of fat by enzymatic or traumatic events
List 4 histological features of necrotic cells
Think about the nucleus and stain colour
- Pyknosis
- Karyorrhexis
- Karyolysis
- Cytoplasm becomes eosinophilic (more pink)
Describe serous exudate
Gross & Histological Features
Clear/yellow watery fluid
No/few cells seen and there is lots of seperation between connective tissue by fluid
Describe catarrhal exudate
Gross & Histological Features
Thick/gelatinous fluid
Connective tissue is separated by mucus
Describe fibrinous exudate
Organ surfaces are red and covered by white/yellow exudate
No/few cells seen and there is lots of fluid with high concentrations of plasma proteins and fibrin (stains bright pink)
Describe suppurative/purulent exudate
Thick white/yellow material
High plasma proteins and cells
Define
Hyperaemia
An active process occurring because of increased blood flow to a tissue
Define
Congestion
A passive process occurring due to decreased outflow of blood from a tissue
List 4 different types of haemorrhage
Think about the size of haemorrhage
- Petechiae
- Purpura
- Ecchymoses
- Suffusive
What is the size of a petechiae haemorrhage
1-2mm in diameter
What is the size of a purpura haemorrhage
3-10mm in diameter
What is the size of a ecchymoses haemorrhage
1-3cm in diameter
What is the size of a suffusive haemorrhage
Think generally
Generalized bleeding across large areas
List 3 factors that determine the significance of a haemorrhage
- Volume
- Rate (fast vs slow)
- Location (interal vs external)
Define
Haemorrhagic diathesis
The increased tendency to haemorrhage after minor injury or spontaneously
List the 4 phases of normal haemostasis
- Vascular response
- Platelet response (primary)
- Coagulation cascade (secondary)
- Fibrinolysis (tertiary)
Summarize
Primary haemostasis
Endothelial injury exposes the ECM for platelets to bind, releasing signals for more platelets to come
Summarize
Secondary haemostasis
Inactive precursors of clotting factor are activated and form thrombin
Thrombin converts fibrinogen to fibrin, which forms a meshwork to stabilize the primary platelet plug
Summarize
Tertiary haemostasis
What is the main goal of tertiary haemostasis?
Plasminogen is converted to plasmin, which cleaves fibrin to fibrin degradation products
Goal is to stop over production of fibirin & control the hemostatic plug
NB: you can use FDPs ( and D-dimers) to diagnose pro-thrombotic states
List 3 disorders of primary haemostasis
- Thrombocytopaenia
- Thrombopathias
- Von Willebrand’s Disease
List 5 reasons for thrombocytopaenia
- Decreased production (in bone marrow)
- Increased destruction or utilization
- Sequestration (in the liver)
- Inherited (common in Cavalier King Charles Spaniels)
- Breed (lower numbers in healthy Sighthounds)
List 2 ways thrombopathias can be aquired
- Inheirted (primary)
- Acquired from neoplasia, kidney/liver disease, infecitous diseases or drugs (secondary)
What is von Willebrand’s factor
An adhesion molecule between platelets and endothelial cells essential for primary haemostasis
Define
Thrombopathias
Abnormalities in platelet function
What is the most common inherited disorder of haemostasis in dogs
von Willebrand’s disease
Define
Haemophilia A
Factor VIII deficiency
Define
Haemophilia B
Factor IX deficiency
What is the reason for disorders of secondary haemostasis
Think deficiency
Coagulation factor deficiencies
List 4 ways disorders of secondary haemostasis can be acquired
Note: other than inheirited
- Vitamin K deficiency/antagonism
- DIC
- Liver/kidney disease
- Infectious diseases
What are disorders of tertiary haemostasis primarily associated with
Disseminated intravascular coagulation (DIC)
This is classified by lots of clots forming
List 3 ways you can evaluate primary haemostasis
What tests can you do?
- Platelet count measurement of vWF function
- Buccal muscosal bleeding time
- Platelet function evaluation
List 3 ways you can evaluate secondary haemostasis
- Measure prothrombin time
- Measure the activated partial thromboplastin time
- Measure activated clotting time or whole blood clotting time
List 2 ways you can evaluate tertiary haemostasis
- Measure fibrin degredation products
- Measure D-dimers
Define
Thrombus
A solid mass of fibrin, platelets and other blood elements formed within a vessel or heart and attached to the wall
List the 3 main factors that predispose the formation of a thrombus
What is the name for these 3 factors?
- Damage to the endothelium
- Altered blood flow
- Hypercoagulability of blood
Virchow’s Triad
