Inflammation

Inflammation And Healing

Dr S PorterUniversity of Cambridge1

What is inflammation?

The bodys response to injuryA protective responseConnected to the repair process

23cycleresolution4time5

6Causes of inflammationCardinal signsSignRubor (red)Calor (hot)Tumor (swelling)Dolor (pain)Functio laesa (loss of function)

Reason

Increased blood flow due to vascular dilatation gives redness and heat.

Increased vascular permeability gives oedema causing swelling.

chemical mediators and mechanical pressure stimulate sensory nerve endings giving pain.

Pain and swelling result in loss of function.

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Vascular dilatation

Fluid escapes from vessels because of endothelial cell Retraction, opening up gap-junctions. Margination-White blood cells move to the margins of the capillaries Exudation of protein-rich oedema Emigration- of polymorphs through vessel wallChemotaxis movement towards chemical mediatorsOpsonisation by immunoglobulins on bacteria provides a fibrin scaffold.

the site of injury8leukocytes margination rolling adhesion emigration of: neutrophils (1-2 days) monocytes (2-3 days)

chemotaxis Although migration of cells was detected from the early days of the development of microscopy (Leeuwenhoek), description of chemotaxis was first made byT W. Engelmann(1881) andW.F. Pfeffer(1884)phagocytosis - lysosomal enzymes,

passive emigration of Red blood cells

910Chemical mediatorsPHAGOCYTOSIS

Recognition and attachmentForeign objects coated withopsonins which attach toreceptors on polymorph surface.

EngulfmentCell membrane fuses around an object.

Lysosomes empty into thevacuole, often before vacuolehas time to seal - this givesrise to 'regurgitation duringfeeding' and enzymatic damageto surrounding tissue.

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Outcomes of acute inflammation1. Resolution - restoration to normal, limited injurychemical substances neutralizednormalization of vascular permeabilityapoptosis of inflammatory cellslymphatic drainage

2. Scar tissue destructionfibrinous inflammtionpurulent inflammation abscess formation (pus)

3. Progress to chronic inflammation

12Chronic inflammationCausespersisting infection prolonged exposure to irritants repeated acute inflammations (PID, tennis elbow)sterile inflammation (silicosis)autoimmune reactions (RA MS)

1314capillariesfibroblastlymphocyteNeutrophylmacrophagethrombocytes12 3

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Days post injuryWhen do specific cells appear following trauma?trauma15Systemic factors

Age Stress IschemiaDiabetesObesityMedication ( NSAIDS)Alcoholism and smokingImmunocompromised conditionsNutrition

The factors affecting healing16Local factorsBone healing 17

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Examples of inflammation:

123456A -Tonsilitis, B - Appendicitis, C - Blister, D - Bursitis, E - Pneumonia, F- Rheumatoid Arthritis Match the inflammation: The End