Pathology Of Inflammation

Question 1

What are the differences between exudate and transudate?

Answer 1

Exudate is fluid that is rich in proteins or cells and contain fibrinogen —> fibrin mesh

Transudate fluid that contains no proteins (normally due to high hydrostatic pressure)

Question 2

Typical features of acute inflammation

Answer 2

Short lived neutrophil rich

Question 3

Typical features of chronic inflammation

Answer 3

Long lived and is lymphocyte and macrophage rich

Question 4

What are the differences between cell-derived inflammatory mediators and plasma derived inflammatory mediators

Answer 4

Cell derived are form platelets, mast cells and and other inflammatory cells that release various chemicals
Platelets —> serotonin
Mast cells —> histamine
Inflammatory cells —> lymphokines and monokines

Plasma derived consists of the
Complement system
Fibrinolytic system and coagulation system
Kinin system

Question 5

What releases PAF and what is the role of PAF in acute inflammation

Answer 5

Cells such as monocytes, macrophages, basophils and mast cells release PAF which causes platelet aggregation. This activates the arachidonic acid pathway that leads to production of prostaglandins + thromboxanes and leukotrienes

PAF can modify permeability of endothelial cells by changing adhesion of polymorphs

• macrophages can be activate by PAF to release more PAF or can also secrete PAF

Question 6

What are the two pathways of arachidonic acid

Answer 6

Cycloxygenase pathway that produces prostaglandins = pain perception and vasodilation
Prostacyclin - inactivate platelets
Thromboxane - vasoconstriction and platelet aggregation

Lipo -oxygenase pathway that produces various forms of leukotrienes
LTB4 = chemotaxis and neutrophil adhesion

LTC4, LTD4, LTE4 = increased vascular permeability and vasoconstriction

Question 7

What are acute phase reactions

Answer 7

Increase in leucocyte production, fever, decrease in blood pressure, and appetite and tachycardia

Question 8

What are other systemic effects of acute inflammation

Answer 8

Pyrogens such as IL-1 and IL-6 can be released (endogenous pyrogen)
Altered liver metabolism of acute phase proteins
HPA axis is altered which leads to metabolic changes and this feeling of malaise

Question 9

What is resolution?

Answer 9

Restoration of normal tissue when architecture is still intact. (If this is not possible then repair occurs)

Question 10

What is organisation?

Answer 10

Scar formation due to loss of structural integrity

Question 11

An example of long term persistent acute inflammation is an absess

Answer 11

Accumulation of neutrophils and is walled off by fibrin mesh so environment remain neutrophil rich
Other inflammatory cells may be present

*formation of an absess is an example of suppurative inflammation

Question 12

Types of chronic inflammation

Answer 12

• non specific = characterised by plasma cells and lymphocytes. Normally supervenes after a bacterial or viral infection
• chronic suppurative eg osteomyelitis
  If eosinophil rich indicates parasitic infection
• granulomatous inflammation = doesn’t start with acute inflammation. Normally a response to agents which are hard to get rid of. Formation of giant cells
• autoimmune = antibodies such as IgM and IgG against body’s own cells
  Plasma cells

Question 13

Resolution is archived through which metabolites:

Answer 13

Resolvins, protectins and lipoxins

Question 14

TB granuloma

Answer 14

Caseating granuloma

Question 15

Sarcoid granuloma

Answer 15

Non-caseating granuloma

Question 16

Basis of immunostaining

Answer 16

Use of antibodies against certain types of molecules or cells

Question 17

Intracellular-vital fluorescent microscopy

Answer 17

Use to see whether cells or molecules are mobile in a granuloma for example

Question 18

Examples of non-invasive imaging

Answer 18

MRI
FFPE sections can yield molecular information