bacterial keratitis priti.PPT

7/21/2019 bacterial keratitis priti.PPT

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Seminar presented by

DR PRITI GUPTA


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Bacterial keratitisBacterial keratitis

Keratitis - Infammation o the cornea.

Microbial keratitis or inectious corneal ulcer

is due to the prolieration o microorganisms(including bacteria, ungi, viruses, andparasites) and associated infammation andtissue destruction within the corneal tissue .

acterial keratitis - most common cause osuppurative corneal ulceration.


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"orneal ulcer- #isruption o the epithelial la$erwith involvement o the corneal stroma.

%uman cornea&s natural resistance to inection.


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BACTERIAL KERATITIS

Needs urgent medical attention

Prompt diagnosis

Initiation of appropriate antibiotic

Limit amount of tissue destruction

Improve patients visual prognosis


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Ocular

DefenseMechanism

hemical Mechanical

Lysozyme

Lactoferrin

Immunoglobulin A

Intact corneal epithelium

(first line of defence)

lin!ing refle"

(reduced bacterial colonization)

#ilia


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'.Most importantdeense barrier- Intact

epithelial la$er

.Maor risk actors-"ompromised

epithelium

*.+recipitating event isepithelial deectproduced b$ trauma,contact lens wear or achronic corneal

disorders.


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PAT!OG"#"SISPAT!OG"#"SIS

Proliferation of bacteria

Adherence to ulcerated epithelium

Invasion into stroma

$igration of neutrophilesProduction of proteniase

Neovascular scar formation #orneal perforation

Inflamatory necrosis

%esmatocele


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Risk

$act%rsf%rBacterial keratits

/I01I" 23"4/1

"4/035 16/23"#I131

"4/035 +I%5I35304/M35II1

171MI""40#II401


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"&TRI#SI $ATORS"&TRI#SI $ATORS

"ontact lens wearrauma

+revious ocular and e$elid surger$5oose corneal sutures

Medication-related actorsImmunosuppression


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%rneal surface disease%rneal surface disease

ear-8lm de8ciencies

3bnormalities o the e$elid anatom$ andunction

Misdirection o e$elashes

3dacent inection9infammation-

lepharitis


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%rneal epithelial abn%rmalities%rneal epithelial abn%rmalities

0eurotrophic keratopath$

/ecurrent corneal erosion"orneal abrasion or epithelial deect

:iral keratitis

"orneal epithelial edema


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Systemic c%nditi%nsSystemic c%nditi%ns

DiabetesSystemic infections

Collagen vascular diseasesImmuno suppressive drug

Chronic alcholismExtensive body burns

Drug addictionAIDS


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Bacterial path%'ens that cause keratitisBacterial path%'ens that cause keratitis

Bacterium Typical characteristics %f infecti%n

&taphylococcus aureus(most common)&taphylococcusepidermidis

Infection progresses slo'ly 'ith little pain

&treptococcuspneumoniae

ypical serpiginous corneal ulcer cornea israpidlyPerforated 'ith early intraocular involvement*verypainful+

Pseudomonas aeruginosa ( most common organismin soft contact lens 'earers)

luish green mucoid e"udate,occasionally 'itha ring shaped corneal abscess+Progressionis rapid 'ith

a tendency to 'ard melting of the cornea over a 'idearea*painful+

6ncommon 4rganisms0eisseria sppMora;ella sppM$cobacterium spp

0ocardia spp"or$nebacterium spp


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-rganismspenetrate intact epithelium

Neisseria gonorroae

.aemophilus agegyptius

#orynebacterium diphteria

Listeria


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Clinical presentation

(SYMPTOMS)

/apid onset of pain#on0unctival in0ection (/edness)

Photophobia

%ecreased vision

%ischarge and lid edema


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#linical features of 1ram positive and 1ram negative

2eature


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&I1N&2+ 3hite stromal infiltrate associated 'ith an

overlying epithelial defect and secondary anterioruveitis +


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. nlargement o stromal in8ltration associated

with stromal oedema


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*.1evere in8ltration and h$pop$onormation


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>.+rogressive ulceration andenlargement o h$pop$on


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?."orneal peroration andendophthalmitis in neglected cases


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acterial corneal ulcers :-

It is a localized suppuration and necrosis of the

corneal epithelium and underlying stroma due to

invasion by bacteria+1tages@

1. Progressive stage:-4rganism adherent to the damaged epithelium to;ins"ollection o +05 +roteol$tic en=$mes

-


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2. Regressive ulcer stage :

- 0ecrotic material is shed oA ulcer will be larger and moredemarcated with regular transparent sloping edges.

3. Stage of healing:

-he epithelium heals b$ migration to cover the ulcer thenregenerates b$ mitosis.

he stroma and owmanBs membrane heal b$ irregular8brous scar. 1o that, once owman&s membrane is inured, a

permanent scar will result. his scar ma$ be dense(leukoma) or aint (nebula). he scar ma$ be vasculari=ed.


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1peci8c orms o keratitis@

'. 1taph$lococci bacterial keratitis Cstaph$lococcuskeratitis occurs more reDuentl$ in compromised corneacases such as bullous keratopath$,chronic herpetickeratitis,keratoconuctivitis sicca,atopic keratoconuctivitis.

acteria grow easil$ on routine culture media as pearl$ whitecolonies.

pearl$ white colonies


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.1treptococcus pneumoniae keratitis @usuall$occurs ater corneal trauma, dacr$oc$stitis, or 8ltering bleb

inection. he ulcer tends to be acute, purulent, and rapidl$progressive with a deep stromal abscess he anteriorchamber reaction is usuall$ severe with marked h$pop$onand retrocorneal 8brin coagulation. 3 culture appearsnonhemol$tic on a blood or chocolate agar plate . +erorationsecondar$ to ulcer is common.


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*. Inectious cr$stalline keratitis

:er$ rare, indolent inection (Strep. viridans)6suall$ associated with long-term topical steroid use+articularl$ ollowing penetrating keratoplast$

Ehite, branching, anterior stromal cr$stalline deposits

reatment@opical antibiotics


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4. Pseudomonas Keratitis

$ost common in contact lens 'ear,burn ,comatose ,

mechanical respiratory patients+

4ello'ish green hue 'ith resistant to treatment+

$ost common in children 5 6 years #ontaminant in hospital,

fluoresnce solutions+

/apidly progressive,destructive !eratitis+

$ay cause infectious &cleritis+

3ithin 7898: h perforation may occur+

&ystemic antibiotic is necessary+


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5.Gonococci Keratitis

.yperacute con0unctivitis , preauricular adenopathy

Penetrate intact epithelium ,produce rapid corneal ulcerationand perforation as 78 to 8: hours after infection+

#hoice of treatment is 2 g ceftria"one I$ or I; for 6 to < days

for !eratitis+

=re>uent irrigation is necessary+

In all hyperacute con0unctivitis the entire cornea must be

evaluated for ulceration +


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F.M$cobaacterium keratitis

hese inections usuall$ arise atertrauma or surgical intervention. he peripher$ o the in8ltrate has a

characteristic Grosted glassG appearance.


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Differential dia'n%sis

Non bacterial infectious

causes of corneal

infiltrates

Non9infectious causes

of corneal infiltrates


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Include fungi (both yeast and mold), parasites (includingprotozoa such as Acanthamoeba), nematodes (such

as Onchocerca), and viral infection+

#%n bacterial c%rneal path%'ens


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#ollagen vascular disorders (e+g+ rheumatoid arthritis, systemiclupus erythematosus), vasculitic disorders (e+g+ polyarteritisnodosa,

3egener?s granulomatosis), and other inflammatory disorders such

as sarcoidosis may produce infiltrative !eratitis+

Systemic diseases


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-ther causes include dermatologic disorders (e+g+

severe ocular rosacea) and allergic conditions (e+g+

vernal !eratocon0unctivitis)+


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Se(uelae and %mplicati%nsSe(uelae and %mplicati%ns

Irregular astigmatism -6neven healing o the stromaIrregular astigmatism.

0on healing corneal ulcer@3 non-healing ulcer is a cornealulceration that is not responding to anti-microbial treatment or aperiod o three to our weeks.

or Ehen the ulcer does not show an$ signs oimprovement or shows worsening despite appropriate and

adeDuate therap$.

"orneal peroration@Most eared complication ma$ result insecondar$ endophthalmitis and possible loss o the e$e.


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%rneal Perf%rati%n%rneal Perf%rati%n

+seudomonas and gonococcal keratitis

"linical presentaion@

1udden relieve o pain/adial olds in descements membrane+eroration o cornea anddesmatocele ormation

reatment @

ectonic keratoplast$


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Pre)enti%n and "arly Detecti%nPre)enti%n and "arly Detecti%n

1creening o patient with high risk actors

ducation on use o e;tended wear contact

lens

+rotective e$e wear or work and sports

reatment o ocular surace disease


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Initial AssessmentInitial Assessment

%istor$4cular s$mptoms

/eview o prior ocular surger$/eview o other medical problems"urrent ocular medications#rug allergies


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;amination


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1lit 5amp iomicroscop$

$elid margins"onunctiva1clera"ornea

3nterior "hamber3nterior :itreous


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Dia'n%stic TestsDia'n%stic Tests

Include corneal scraping to obtain specimens or microbiologicalstainings and cultures to isolate the causative organism anddetermine sensitivit$ to antibiotics.

he maorit$ o communit$-acDuired cases o bacterial keratitisresolve with empirical therap$ and are managed without smears orcultures.

+rior to initiating antimicrobial therap$, smears and cultures areindicated in cases where the corneal in8ltrate is central, large, deep,

is chronic in nature, or has at$pical clinical eatures suggestive oungal, amoebic, or m$cobacterial keratitis.

In addition, cultures are helpul to guide modi8cation o therap$ inpatients with a poor clinical response to empirical treatment and todecrease to;icit$ b$ eliminating unnecessar$ drugs.


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StainsStains

Microbial pathogens ma$ be categori=ed b$ e;aminingstained smears o corneal scrapings

Stain Or'anisms )isuali*ed

1ram stain est for bacteria* can also visualizefungi, Acanthamoeba

1iemsa stain acteria,

fungi,Chlamydia, Acanthamoeba

Acid fast Mycobacterium, Nocardia

#alcofluor 'hite =ungi, Acanthamoeba


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ulturesultures

"orneal material is obtainedb$ scraping corneal tissuesrom the advancing borderso the inected area.

4btaining onl$ purulentmaterial usuall$ results ininadeDuate $ield.

"ultures o contact lenses,lens case, and contact lenssolution ma$ provideadditional inormation to

guide therap$


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U+TUR" M"DIA $OR BAT"RIA+U+TUR" M"DIA $OR BAT"RIA+

,"RATITIS,"RATITIS

Standard Media Common Isolates

Blood agar Aerobic and facultatively anaerobic bacteria, including !aeruginosa, S! aureus, S! epidermidis, S! pneumoniae

Chocolate agar Aerobic and facultatively anaerobic bacteria, including "!

influen#ae, $! gonorrhea, and Bartonella species

%hioglycollate broth Aerobic and facultatively anaerobic bacteria

Supplemental Media

Anaerobic blood agar &CDC,

Schaedler, Brucella'

! acnes, eptostreptococcus

()*enstein+ensen medium -ycobacteria species, $ocardia species

-iddlebroo. agar -ycobacteria species

%hayer+-artin agar athogenic $eisseria species


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%rneal Bi%psy%rneal Bi%psy

5ack o response

More that ' negative

culture result

#eep stromal in8ltratewith normal overl$ing

tissue


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1oals of therapy

/apid elimination o bacteria

/eduction o infammator$ response

+revent o structural damage

+romotion healing o epithelial


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Treatment

Initial opical antibiotic eye drops are able to achieve high

tissue levels and is the preferred choice of treatment inmost cases+

opical antibiotic ointment at bedtime may be useful inless severe cases as an ad0unctive treatment+

&ub9con0unctival antibiotics maybe helpful in cases ofimminent scleral spread or perforation +

&ystemic therapy maybe useful in cases 'here there isscleral or intraocular involvement or systemic infection(gonorrhea)


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&ingle@drug therapy

sing fluoro>uinolones sho'n to be as effective as

combination fortified antibiotics+

/ule of 7 57mm diameter, 57BA# cells C D7mm from

visual a"is+


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%mbinati%n $%rtified-Antibi%tic. Systemic Therapy

&evere infections

Previously unresponsive to single9drug therapy

&ystemic Infection e"tending to sclera

Impending or fran! perforation

1onococcal !eratitis


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=ortified therapy for bacterial !eratitis

4rganism 3ntibiotic opical dose

mg9ml

0o organism ormultiple t$pes o organisms

"ea=olin Eithobram$cin or

2luoroDuinolones

? mg9ml

* mg9ml


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reatment

&evere !eratitis may re>uire a loading dose

(Every


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$odification of herapy

Efficacy of treatment is 0udged primarily on the clinicalresponse to'ards the current treatment+

#ulture results may have an impact on modification of

therapy especially 'hen the response to treatment is poor

$odification should be done if the eye sho' lac! ofimprovement or stabilisation after 8:9F7hrs after treatment +


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$eatures su''esti)e %f p%siti)e resp%nse t% treatment

/eduction in pain /educed amount of discharge Lessened eyelid edema or con0unctival in0ection %ecreased density of the stromal infiltrate in the absence

of progressive stromal loss

/educed stromal edema and endothelial inflammatorypla>ue

#onsolidation and sharper demarcation of the perimeterof the stromal infiltrate

/educed anterior chamber cell, fibrin, or hypopyon

Initial re9epithelialisation #essation of progressive corneal thinning +


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$ot to be use in initial phase

rednisolone acetate /0 1ID

atient must have fre2uent follo*+up

Topical

Corticosteroid undercoverage

of antibiotics

Inhibit chemotaxis &

phagocytosis

Recurrent

of

infection

Reduced stromal

inflammatory reaction

Limit tissue destruction by PMN

and neovascuariation !ith scar


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yan%acrylate tissue adhesi)e

#yanoacrylate tissue adhesive (N9butyl979

cyanoacrylate) has been used to treat

progressive corneal thinning, descemetocele,

and corneal perforation 'ith satisfactoryresults+

In addition to its tectonic support and

bacteriostatic effects, the tissue glue can

arrest !eratolysis by bloc!ing leu!ocytic

proteases from the corneal 'ound+

Perforations up to 7@6 mm in diameter can besealed by the tissue adhesive+

Necrotic tissue and debris should be removed

from the ulcer bed prior to application of the

glue+

%ue to potential corneal to"icity, only the

minimum amount of glue re>uired to cover thedefect should be used+

he adhesive is usually left in place until it

dislodges spontaneously or a !eratoplasty is

performed+

%lla'en r%ss linkin'


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#ollagen cross lin!ing (#GL) of the cornea has been developedrecently as a ne' treatment for multidrug9resistant infectious!eratitis+

his techni>ue has sho'ed promising results specially in patients'ith corneal melting and impending perforation+

#orneal melting has been arrested and complete epithelializationachieved in several cases+

he success rate 'as higher for bacterial infections than fungal

infections+

%lla'en r%ss linkin'


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auteri*ati%nauteri*ati%n

+erormed b$ - +ure carbolic acid (')

ricloacetic acid('-)+arts touched immediatel$ turns white,normal

epithelium rapidl$ recovers.

"ontraindications Culcers with e;cessive thinning orperorated crneal ulcers

Sur'ical Mana'ement


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Sur'ical Mana'ement

'."onunctival fap@ "onunctival fap has been

used to treat recalcitrantmicrobial keratitis.

he fap can bring bloodvessels to the inected area,promote healing, and provides

a stable surace covering. 3 conunctival fap isparticularl$ useul in cases ononhealing peripheral cornealulcer, where the fap can beplaced without compromisingvision.

.Keratoplast$

*.3mniotic membranetransplantation (3M) can stabilise

the cornea incases o corneal melt and

descemetocele.


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bacterial keratitis priti.PPT

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