Red Eye

1. Red Eye Jahangir Sadeghi MD 1391

2. We approach to RED Eye through pathology 1) Inflammation 2) Infection

3. Inflammation is not synonymous with infection Inflammation is a response of tissue to a noxious stimulus . This noxious stimulus may be infectious or noninfectious

4. Causes of noninfectious inflammation A . Exogenous causes include 1: Physical-surgical 2: Trauma 3: Thermal & Radiant energies Alkali 4: Chemical Acid 5: Allergic

5. B – Endogenous Causes 1) Necrosis of intra ocular tumor Ischemic Immune basis 2) unknown cause as most cases of uveitis

6. Infectious causes : 1) Bacterial 2) Viral 3) Rickettsial 4) Fungal 5) Parasitic

7. Phases of Inflammation : 1) Acute “ immediate or shock ” phase 2) Subacute phase. “ immune process” 3) Chronic phase

8. Acute phase of inflammation A- Five cardinal signs : 1) Redness 2) heat 3) Tumor or mass 4) Pain 5) Loss of function

9. ( Acute phase ) B- Is related to histaminrelase from mast cells ( lasting from 3 to 5 hours ) and maintained by chemical mediators

10. Histamine and chemical mediators 1- Histamine is found in granules of mast cell & polymorphonuclear leukocyte 2) Serotonin - Is found in granules of mast cell & platelates - Is a vasoactive agent 3) Kinins 4) Plasmin –An enzyme for fibrinolysis

11. 5) Complement system – consists of 8 Alpha or Bata Globulins and one gamma Globulins Biologic functions (C.S) A-histaminrelase B-facilitation of phagocytosis of foreign protein

12. 6) Prostaglandins – Fatty Acids Function 1- contraction of smooth muscle 2- Vasodilatation 3- platelet aggregation inhibitory action

13. Phisiopathalogy of acute phase of an injury 1) Immediately , arterioles contract “ abut 5 minutes ” Then they relax and dilate from the chemical mediators 2) Release of heparin by mast cells helps to prevent coagulation in blood vessels “ at the area of injury “

14. 3) During the early period following an injury the leukocytes “ predominantly polymorphonucleor“ (P.M.N) stick the vessel walls and prolonged and pass through vessel walls _ PMN are the main inflammatory cells in acute phase _ First line of defense _ Start to phagocytosis and lysosomal digestion _ When PMN cell die they liberate proteolytic enzymes that produce tissue necrosis

15. Acute phase is an exudative phase What is exudation & Transudation Exudation is passage of protein – containing fluid and cells through opened endothelial vascular cells into surrounding tissue “ inflammatory exudate in uveitis “ Transudation is passage of fluid through intact vessel wall into surrounding tissue . (so protein content is low or nil ) (Transudation of aqueous)

16. Diffrent type of exudate 1) Serous exudate – composed of protein seen clinically in aqueous “Flare in anterior chamber “ 2) Fibrinous exudate - high fibrin content in “ Plastic irritis“ 3) Purulent exudate – composed of PMN and necrotic products in “Hypopyon“ 4) Sanguineous exudate – is composed of erythrocytes as in “Hyphema“

17. 1 – Acute inflammation 2 – Subacuteinflammation 3 – Chronic inflammation

18. Subacuteinflammation 1 – PMN release lysosomal enzymes lysosomal enzymes increase capillary permeability and cause tissue destruction . So (necrosis – recurrence and chronicity is seen in this phase ) 2 – Monocytes “ Macrophages “ are the second line of cellular defense in this phase

19. What is lysosomal enzymes (including collagenase ) 1: Released by-PMN -MN - Epithelial cells and kerotocytes in corneal ulcers 2: Result in tissue destruction

20. MN cells arrive after PMN followed by ingrowth of capillaries – New vessels leak fluid and leukocytes “ PMN . M.N “

21. Infection 1) Not all infectious agents are injurious 2) certain microbes can live within tissue without damaging their host 3) The first requirement of infectious agent is that it gain entry into the host . Principal portals of entry are natural orifices 4) Few organism can pierce the intact skin 5) An organism my by non pathogenic in one site but pathogenic in another

22. 6) Infectious agents employ one or both of two main pathogenic mechanisms a: invasiveness b: formation of toxins 7) Bacterial toxins are two main types a: Exotoxin – produced by gram + b:Endotoxin – produced by gram -

23. What is Coagulase ? Certain strains of staph.produce a deposition of fibrin on the surface of organism , forming a capsule which protect it from phagocytosis

24. What is Hyaluronic Acid ? _ A viscous , polysaccharide acid is present of Intercellular ground substance of many tissues. Many bacteria produce enzymes which hydrolyze H.A _ Consequently , ground substance of interacellular becomes fluid and bacteria and toxins diffuse throughout the tissues easily

25. Anti – inflammatory properties of cortico steroids 1) They have capacity to prevent or suppress the development of local heat – redness & swelling 2) At the microscopic level they inhibit from edema – fibrin deposition – capillary dilatation migration of leukocyte's , capillary proliferation fibroblast proliferation etc.

26. 3) Underlying cause of the disease remains USE ENOUGH SOON ENOUGH OFTEN ENOUGH LONG ENOUGH

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