EYE INFECTIONS Ndonga T A Msc TID I

EYE INFECTIONS Ndonga T. A Msc TID I

Anatomy

Anatomy

Anatomy The anterior chamber is the area bounded in front by the cornea and in back by the lens, and filled with aqueous. The aqueous is a clear, watery solution in the anterior and posterior chambers. The artery is the vessel supplying blood to the eye. The canal of Schlemm is the passageway for the aqueous fluid to leave the eye.

Anatomy The choroid , which carries blood vessels, is the inner coat between the sclera and the retina. The ciliary body is an unseen part of the iris , and these together with the ora serrata form the uveal tract. The conjunctiva is a clear membrane covering the white of the eye (sclera). The cornea is a clear, transparent portion of the outer coat of the eyeball through which light passes to the lens.

Anatomy The iris gives our eyes color and it functions like the aperture on a camera, enlarging in dim light and contracting in bright light. The aperture itself is known as the pupil The lens helps to focus light on the retina. The macula is a small area in the retina that provides our most central, acute vision. The optic nerve conducts visual impulses to the brain from the retina. The ora serrata and the ciliary body form the uveal tract, an unseen part of the iris.

Anatomy The posterior chamber is the area behind the iris, but in front of the lens, that is filled with aqueous. The pupil is the opening, or aperture, of the iris. The rectus medialis is one of the six muscles of the eye. The retina is the innermost coat of the back of the eye, formed of light-sensitive nerve endings that carry the visual impulse to the optic nerve. The retina may be compared to the film of a camera. The sclera is the white of the eye. The vein is the vessel that carries blood away from the eye. The vitreous is a transparent, colorless mass of soft, gelatinous material filling the eyeball behind the lens.

anatomy The eyeball is protected anteriorly by the eyelids And contained in the orbit

Normal flora of the eye Predorminant organisms Diphtheroids S. epidermidis Non hemolytic strep

Eye infections Ø Ø The infections could be: Acute Chronic Primary secondary

conjunctiva Conjunctivitis is the most common ocular inflammation Clinical manifestations-hyperemia, secretion – due to exudates of inflammatory cells and fibrin rich edematous fluid-which may be purulent, mucopurulent, fibrinous or serosanguinous depending on the cause. When the exudate dries , the eyelids stick together

conjunctiva The normal transparency may be lost Papillae may form especially in tarsal conjunctiva Symptoms include gritty eyes, photophobia, diminished vision and pain

Organisms implicated *Strep pneumo . C. diphtheria Strep pyogenes . M. tuberculosis strep viridians . francisela *Staph aureus . T. pallidum *H. influenza . moraxella *N. gonorrhoea/meningitidis H. ducreyi . shigella flexeneri Proteus vulgaris . Y. enterocolitica

organisms Staph epidermidis Acinetobacter Aeromonas hydrophila Peptostreptococcus Bartonella * most common

conjunctivitis

Routes of entry-hand to eye -airborne formites -contact with URTIs -contact with genital tract infections -spread from adjacent structures-face and eyelids, sinuses -Hematogenous spread -rare

Determinants of infective agents Age-neisseriae /chlamydia-newborns Children-influenza, strep pneumo, staph aureus Young adults-strep pneumo, staph aureus/epidermidis

Management/control Mostly self limiting Px education-hand washing! Rx-topical gentamicin/tobramycin-gram neg Neomycin/polymixin-gram pos Topical quinolones-severe infections Parenteral ceftriaxone for gonococcal Erythromycin syrup for chlamydia in neonates/erythromycin ointment.

Cornea Inflammation of the cornea Clinically presents as loss of vision, , tearing, photophobia and blepharospasm, ulceration Symptoms-foreign body sensation, pain

Organisms implicated Gram pos cocci- gram neg bacilli *Staph aureus . *pseudomonas Staph epidermidis . proteus Strep viridans . klebsiella Strep pyogenes . serratia Strep fecalis . E. coli Peptostreptococcus * most common *Strep pneumo

organisms Gram neg coccobacilli gram-positive bacil Moraxella corynebacterium Pasturella c. tetani/c. perfringen Morganella bacillus cereus Serratia spirochetes E. coli treponema Aeromonas borrelia burgdoferi mycobateria-tb, mac

Routes of entry/predisposing factors Direct penetration-organisms producing toxins/enzymes/virulent factors-neisseria Following injury, eyelid abnormalities, tear dysfuntional states, corneal anesthesia Immunocompromised states Use of contact lenses

Treatment Broad spectrum antibiotics used pending lab results-cephalosporins +aminoglycosides Aminoglycosides can be used synergistically with ticarcillin. Quinolones-pseudomonas and gram negatives Use topical antibiotics Parenteral-severe cases Steroids? ?

Endophthalmitis Most cases develop after intraocular surgerycataract surgery. Organisms involved-microflora Clinically-decreased visual acuity, pain, hypopion, hyperemia

organisms Staph aureus . E. coli Staph epidermidis . H. influenza Strep pneumo . klebsiella Bacillus cereus . moraxella Corynebacteria spp . proteus Listeria . pseudomonas N. meningitidis . s. typhimurium Acinetobacter . serratia Enterobacter . clostridium Propiono bacterium acnes treponema pallidum Actinomyctes israeli . m. tuberculosis/leprae

Treatment Is according to culture and sensitivity Iv antibiotics-3 G cephalosporins Intravitreal vancomycin-s. aureus Sx-vitrectomy Steroids? ?

Periocular infections These involve orbit and cellular adnexa Principal periocular structure susceptible to infections are eyelids , the components of lacrimal apparatus and the orbit.

Eyelids Inflammation of the lid margins-blepharitis Often chronic and bilateral Two types-anterior-staphylococcal -posterior-meibominitis Organisms Staphaureus, epidermidis, pseudomonas, proteus, moraxella. Mascara used has been implicated

Eyelids Erysipelas-acute cellulitis –strep pyogenes, staph aureus-invasion of subcutaneous after trauma Hordeolum-internal/external depending on glands involved-staph implicated Internal-meibomian gland infection External-stye infection of glands of zeis sebaceous gland of eye lids

Lacrimal apparatus Produce the aqueous component of tear film Canaliculitis-chronic inflammation of canaliculiby propionibacterium, actinomyces Dacrocystitis-inflammation of lacrimal sacstreppneumo, staphaureus, pseudomonas, chla mydia, h. influenza in children Clinically-epiphora

Lacrimal app Dacroadenitis-inflammation of main lacrimal gland-staph, strep, tuberculosis-chronic

Orbit and carvenous sinus Cellulitis-pre septal anterior orbit septum and post septal-orbital contents Serious-loss of sight and spread to carvenous sinus leading to thrombosis and death,

causes Spread from contiguous structures like sinuses, dental, intracranial infections Direct innoculation after puncture wounds Retained foreign bodies-sutures After surgery After fractures Sequelae of dacrocystitis Bacteremia in kids H. influenza, E. fecalis

organisms Staph aureus Strep pyogenes Strep pneumo Clostridia H. influenza-<5 s Tb-hematogenous spread

Clinical Evidence of trauma-bleedng, fever, lid edema and rhinorrhoea. Pain, headache, loss of vision Tenderness, black eye, proptosis

Treatment Blepharitis-Topical –bacitracin, erthromycin Steroids-reduce inflammation Hordeolum-warm compresses and sytsemic antibiotics if multiple or no response I&D if not responding to rx Canalliculitis-antibiotic irrigation with penicillin G Dacrocystitis-oral penicillin+warm compresses

treatment Dacroadenitis-systemic antibiotics Cellulitis-cloxacillin, cephalexin Clindamycin for gram neg Iv antibiotics orbital cellulitis

Approach to diagnosis of eye infections Mostly clinical diagnosis Slit lamp examination Swabs –conjunctiva, abscesses etc Cultured on BA Swab each anaesthetized eye separately Can also do scrapings-cornea Vitreous/aqueous humour aspiration- endophthalmitis

diagnosis Gram stain ELISA Dna/pcr-chlamydia Fluorescent microscopy u/s, ct, MRI for cellulitis

JE UME CHUKUA KURA?