Red Eye

Jahangir Sadeghi MD1391

1) Inflammation2) Infection

We approach to RED Eye through

pathology

Inflammation is a response of tissue to a noxious stimulus . This noxious stimulus may be infectious or noninfectious

Inflammation is not synonymous with infection

A . Exogenous causes include

1: Physical-surgical 2: Trauma 3: Thermal & Radiant energies Alkali 4: Chemical Acid 5: Allergic

Causes of noninfectious inflammation

B – Endogenous Causes 1) Necrosis of intra ocular tumor Ischemic Immune basis

2) unknown cause as most cases of uveitis

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

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

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

Acute phase of inflammation

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

1- Histamine is found in granules of mast cell & polymorphonuclear leukocyte2) Serotonin - Is found in granules of mast cell & platelates - Is a vasoactive agent3) Kinins4) Plasmin –An enzyme for fibrinolysis

Histamine and chemical mediators

5) Complement system – consists of 8 Alpha or Bata Globulins and one gamma GlobulinsBiologic functions (C.S)A- histamin relaseB- facilitation of phagocytosis of foreign protein

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

1) Immediately , arterioles contract “ abut 5 minutes ”Then they relax and dilate from the chemical mediators2) Release of heparin by mast cells helps to prevent coagulation in blood vessels “ at the area of injury “

Phisio pathalogy of acute phase of an

injury

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

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)

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 “

Diffrent type of exudate

1 – Acute inflammation2 – Subacute inflammation3 – Chronic inflammation

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

Subacute inflammation

What is lysosomal enzymes (including collagenase ) 1: Released by - PMN - MN - Epithelial cells and kerotocytes in corneal ulcers2: Result in tissue destruction

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

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 orifices4) Few organism can pierce the intact skin 5) An organism my by non pathogenic in one site but pathogenic in another

Infection

6) Infectious agents employ one or both of two main pathogenic mechanisms a: invasiveness b: formation of toxins7) Bacterial toxins are two main types a: Exotoxin – produced by gram + b:Endotoxin – produced by gram -

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

What is Coagulase ?

_ 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

What is Hyaluronic Acid ?

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.

Anti – inflammatory properties of cortico steroids

3) Underlying cause of the disease remains

USE ENOUGH SOON ENOUGH OFTEN ENOUGH LONG ENOUGH

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