Acute and Chronic Inflammation

Question 1

Define inflammation

Answer 1

• A physiological response to tissue injury with vascular and cellular components
• Terminates in resolution, repair or continues

Question 2

What are the features of inflammation?

Answer 2

• Redness (rubor)
• Heat (calor)
• Swelling (tumour)
• Pain (dolor)
• Loss of function (function laesa)

Question 3

What vascular changes occur in inflammation?

Answer 3

• Vasodilation (due to histamine or NO on vascular smooth muscle)
• Increased vascular permeability (permits escape protein rich fluid exudate into extravascular tissue, caused by contraction of endothelial cells so increased interendothelial spaces, mediated by histamine/bradykinin/substance P and is caused by neutrophils
• Vascular congestion/stasis
• Endothelial activation

Question 4

What cellular factors are involved in inflammation?

Answer 4

• Margination (WBCs move peripheral due to stasis)
• Rolling (WBCs stick and detach from wall)
• Adhesion
• Migration (across endothelium)
• Chemotaxis (travel along a chemical gradient)

Question 5

What receptors are involved in leukocyte activation and recognition of microbes?

Answer 5

• Toll-like and G-protein coupled receptors on PMNs and macrophages
• Opsonins receptors on leukocytes
• Cytokine receptors on leukocytes

Question 6

What are the features of an exudate?

Answer 6

• High protein (>30g/l) and cellular content
• LDH >2/3 ULN
• Pleural/serum protein ratio >0.5
• Pleural LDH/serum LDH ratio >0/6
• Usually unilateral
• Clear, cloudy or blood-stained
• Allows delivery of nutrients, dilution of toxins, entry of antibodies and stimulates immune response

Question 7

What are the features of a transudate?

Answer 7

• Low protein (<30g/l) and cellular content
• LDH <2/3 ULN
• Often bilateral
• Usually clear

Question 8

What do neutrophils do in the inflammatory process?

Answer 8

• Involved in opsonisation, phagocytosis and intra-cellular killing of microorganisms

Question 9

What do mast cells do in the inflammatory process?

Answer 9

• Reside in tissues and contain histamine and heparin in preformed granules
• Release in inflammation
• Have a role in allergy/anaphylaxis

Question 10

What do macrophages/monocytes do in the inflammatory process?

Answer 10

• Involved in chemotaxis and synthesise TNF, IL-1 and IL-6
• Involved in phagocytosis and act as APCs

Question 11

List some plasma factors involved in the inflammatory process

Answer 11

• Kinin system (alters vascular permeability and mediates pain)
• Coagulation system (conversion of fibrinogen to fibrin - forms inflammatory exudate)
• Fibrinolytic system (plasmin lyses fibrin into fibrin degradation products)

Question 12

List the features of SIRS

Answer 12

• Temperature <36oC or >38oC
• HR >90bpm
• RR >20/min or PaCO2 <32mmHg
• WCC <4x10*9/L or >12x10*9/L

Question 13

List the sources and actions of histamine

Answer 13

• Vasodilation
• Increased vascular permeability
• Endothelial activation

Question 14

List the sources and actions of serotonin

Answer 14

• Vasodilation
• Increased vascular permeability

Question 15

List the sources and actions of prostaglandins

Answer 15

• Vasodilation
• Pain
• Fever

Question 16

List the sources and actions of leukotrienes

Answer 16

• Increased vascular permeability
• Chemotaxis
• Leukocyte adhesion and activation

Question 17

List the sources and actions of platelet activating factor

Answer 17

• Vasodilation
• Increased vascular permeability
• Chemotaxis
• Leukocyte adhesion
• Degranulation
• Oxidative burst

Question 18

List the sources and actions of NO

Answer 18

• Vascular smooth muscle relaxation
• Killing of microbes

Question 19

List the sources and actions of IL-1, TNF and IL-8

Answer 19

• Endothelial activation
• Fever
• Pain
• Shock

Question 20

List the sources and actions of chemokines

Answer 20

• Chemotaxis
• Leukocyte activation

Question 21

List the sources and actions of complement

Answer 21

• Leukocyte chemotaxis and activation
• Vasodilation

Question 22

List the sources and actions of kinins

Answer 22

• Increased vascular permeability
• Smooth muscle contraction
• Vasodilation

Question 23

Define chronic inflammation

Answer 23

• Persistent (more than 3 months) and lacks resolution when the inflamed tissue is unable to overcome the effects of the injurious agent

Question 24

What is granulomatous inflammation?

Answer 24

• Sub-type of chronic inflammation and are formed by epithelioid macrophages and lymphocytes
• Lymphocytes secrete the right kind of cytokines causing macrophages to multinucleate and form a ball
• Causes include infectious agents, foreign material, sacroidosis, Crohn’s disease and response to tumours

Question 25

Describe the inflammatory stage (stage 1) of wound healing

Answer 25

• Haematoma forms, prostaglandins recruit neutrophil polymorphs, macrophages, lymphocytes, and fibroblasts to the site of njury
• Granulation tissue, ingrowth of vessels, migration of mesenchymal cells occurs

Question 26

Describe the proliferation stage (stage 2) of wound healing

Answer 26

• Fibroblasts lay down stroma
• Collagen matrix is laid down
• Osteoid is secreted and mineralised leading to soft callus formation which then ossifies after 4-6 weeks

Question 27

Describe the maturation stage (stage 3) of wound healing

Answer 27

• Occurs slowly over months-years
• Facilitated by mechanical stress

Question 28

What are the causes of a transudate?

Answer 28

• Cardiac failure
• Hepatic cirrhosis
• Nephrotic syndrome
• Hypoalbuminaemia

Question 29

What are the causes of an exudate?

Answer 29

• Bacterial pneumonia
• Malignancy
• Mesothelioma
• TB