Cornea: Keratitis Flashcards
How do you tell which type of keratitis it is?
If in centre of cornea (central 3-4mm) it is more likely to be infectious
If in periphery (near limbus with conj vessels) it is more likely to be sterile (e.g. marginal keratitis, peripheral ulcerative keratitis)
Describe marginal keratitis & its treatment?
- More common
- Immune mediated inflammation as result of blepharitis & lid margin disease
- Usually occurs where lid touch globe/cornea
o More likely to be 4 to 5 o’clock position, 7 to 8
o’clock position, 10 to 11 o’clock position, 2 to
3 o’clock position - Always a small area of clear cornea between the limbus
and the infiltrate - Infiltrate may appear as white patch
Treatment: - Ongoing lid hygiene advice
- Combo of antibiotic & steroid (as inflammatory)
–> antibiotic: chloramphernicol 4x a day for 2 weeks
After that lid hygiene & ocular lubricants for any associated dry eye
Describe Superficial Punctate Keratitis?
- Common
- Descriptive term
- Pebble-dashed appearance of epithelium
- Endothelium becomes oedematous & NaFl can gather in between unhealthy epithelial cells
- Common in dry eye & people who wear CLs
Describe the most common ways that ocular surface infections are spread?
- Opportunistic exposure and contact
o Airborne
o Finger
o Contact lenses – majority in young pxs – easy to transfer pathogens into eye, any micro abrasion can lead to the pathogen causing an infection – since cornea is avascular, infection can take hold quite quickly & cause significant
degree of damage before body can amount a
immune response
o Extension from lids
o Upper respiratory tract infection
o Sexual contact
Describe molluscum contagiosum?
Px can have ongoing ocular signs of inflammation - doesn’t matter what put on eye - this will continue to shed pox virus causing recurrent infections
Needs moluscum removed
Describe Peripheral keratitis?
If BVs growing over cornea, then know it has been there for a while - BVs do not just grow over night - take weeks or months
If infection encroaching on centre then more likely to be immune mediated –> px will have dermatitis so do not just look at the eye
Look at the px too
Describe herpes simplex virus (HSV) keratitis?
- Symptoms:
o FB sensation
o Photophobia
o Redness
o Blurred vision – if ulcer involves central cornea & visual axis - Can involve just the eyelid – get small white vesicles
- Epithelial Ulcer:
o Dendritic pattern – multiple small branches with small bulbs
o Stain w/ NaFl
o Terminal bulbs
o Swollen adjacent epithelium
o If edges of ulcer start to separate & whole thing starts to enlarge geographic ulcer - Assess for corneal sensation – just use tip of tissue & ask px if they can feel it when you touch the surface of their eye (will be able to tell as they would blink if they could feel it)
o These pxs would not blink and may not feel anything
o If unsure, use other end of tissue and test other eye - Reduced corneal sensation:
o Focal or diffuse - Conjunctival injection
- Underlying stromal oedema – due to break in epithelium
- After resolution:
o Stromal scarring
o Ghost dendrite – scar in pattern of dendritic ulcer
Describe the management for HSV keratitis?
o Referral of acute episodes w/ no history
o Recurrent cases:
Clear diagnosis
Only epithelial involvement
Commence topical antiviral therapy – acyclovir/ganciclovir 5 times a day
o Refer if non-healing after 1 week or if there is stromal involvement
o Topical antiviral therapy:
Acyclovir 3% ointment 5 times daily
Review one week
Therapy longer than 2 weeks induces keratopathy
o Debridement w/ cotton bud
o Oral acyclovir:
800mg 5 times daily
Maintenance dose of 400mg 2 times daily in recurring disease
o Topical steroids must be discontinued
If px on topical steroids when present to you w/ epithelial HSV then DISCONTINUE as will affect healing process
Describe HSV Disciform keratitis?
- Endotheliitis
- Often has circular lesion (disc)
- Associated uveitis
Describe HSV Stromal keratitis?
- Herpetic Eye Disease Study (HEDS)
- Oral antiviral – acyclovir – systemic preferred as topical normally doesn’t penetrate deeper than epithelium
- Topical steroid – Pred forte 4x day – to control inflammation
- Reduces persistence / progression
- Shortens duration
- Long term prophylaxis – reduced no. of recurrences px can have and lessens severity of episode if it does occur
Describe Herpes Zoster Ophthalmicus (HZO)?
- Reactivation of latent virus – px had chicken pox in past
- Associated w/ altered immunity
- Zoster dermatitis:
o Vesicular rash – respects vertical midline
o General malaise
o Multitude of ophthalmicus signs - Hutchinson’s Sign: rash extending to tip of nose, if see this then the nasociliary nerve has been involved & as that travels through orbit, px is more likely to have ocular signs
- Investigations:
o Detailed history & symptoms
o Full examination – dilated to make sure no evidence of vitritis, retinitis or optic neuritis
o Pxs can also have cranial nerve palsies so important to investigate ocular motility too
Describe the management for Herpes Zoster Ophthalmicus?
o Rest & supportive advice
o Advice on avoiding contact with immunocompromised patients
Consider elderly, infants, pregnant females (in 1st trimester)
o Epithelial disease – lubricants
o Analgesia
o Limited to epithelium – Manage jointly with GP if have ongoing neuralgic pain
o Referral if deeper layers involved
Compare the epithelial changes of HSK vs VZV?
- Dendrites:
o HSV – Central ulceration with terminal bulbs. Geographic if steroids used
o VZV – Smaller without central ulceration or terminal bulbs - Dermatomal distribution – respects midline
- Skin scarring
- Neuralgia – often after initial rash settles there is on going inflammation of the dermatomal distribution causing significant neuralgic type pain – can be ongoing for many months, px will need neuralgic type analgesia
- Iris atrophy
- Recurrent disease
Describe bacterial keratitis? & ulcers?
- Sight and eye threatening condition
- Variable speed of onset
- Rapid onset with significant inflammation
- Can progress to corneal perforation
- Requires urgent referral
- Take appropriate history
- Associated with epithelial disruption:
o Contact lens wear – send the CL to microbiology lab
o Trauma
o Contaminated topical ocular medications – send this to microbiology lab
o Impaired defence mechanisms
o Altered structure of corneal surface – hx of chronic corneal erosions? Chronic dry eye? - Ulcers:
o Sharp epithelial demarcation
o Underlying dense, suppurative stromal inflammation Indistinct edges surrounded by stromal oedema
o Presentation can vary from quick onset and aggressive course to slow, indolent course
Describe CL related keratopathy management?
- Discontinue of lens wear 2-14 days
- Advice against extended wear – if start CLs again wear for short time
- Lid hygiene in presence of blepharitis
- Appropriate type of contact lens wear
- Refer if infective component suspected
Describe the clinical presentation of bacterial keratitis?
- Rapid onset of pain
- Conjunctival injection
- Photophobia
- Decreased vision – if ulcer is on visual axis
- Rate of progression depends on virulence of organism
Describe the clinical presentation of pseudomonas bacterial keratitis?
- Pseudomonas typically produces stromal necrosis with a shaggy surface and adherent mucopurulent exudate
- V aggressive
- Endothelial inflammatory plaque
- Marked anterior chamber reaction
- Hypopyon – can develop over course of an hour
- Slow growing, fastidious organisms
o Mycobacterium
o Anaerobes
o Non-suppurative infiltrate
o Intact epithelium
What is the management for non-vision threatening bacterial keratitis?
Non-vision threatening = epithelial defects or infiltrate 1mm or less in size, pxs vision is not reduced and no hypopyon still needs aggressive treatment
* Topical Quinolones – broad spectrum
o Ofloxacin
o Ciprofloxacin
* Every 1 – 2 hourly from at least 7am to 10pm
* Cyclopentolate 1% TDS (three times a day) – to reduce ciliary spasm & to increase comfort
* Review within 48 hours – over 1st day or 2 eye can feel worse especially if treating gram -ve bacteria
* Tapering as necessary
* Mild topical steroids once infection controlled ± organism identified (not 1st line tx) – too many steroids can make it worse
What is the management for vision threatening bacterial keratitis?
Vision threatening = Larger epithelial defects affecting central visual axis – vision dropping down to hand movements or light perception – may have hypopyon
* Tx must be more aggressive
* Consider admission – depends on individual – e.g. if px is 80, lives on own, has rheumatoid arthritis and can’t put drops in then they would be more likely to be admitted than a 20/30 year old who lives near by
* Hourly:
o Day and night is needed
o Preservative free Cefuroxime 5%
o Preservative free Gentamicin 1.5%
o Taper after 48hours
* Cycloplegic
* Systemic antibiotics
o Oral ciprofloxacin 750mg BD
What are the signs of improvement in bacterial keratitis?
- Blunting of perimeter of infiltrate
- Decreased density of stromal infiltrate – starts to fade, becomes more greyish
- Reduction of stromal oedema
- Reduction of anterior chamber activity – hypopyon starts to shrink and disappear, cells will disappear too
- Epithelial recover
- Cessation of corneal thinning
- Eventually left with mild corneal scar
Describe fungal keratitis?
- Less common
- Warmer, more humid areas
- Predisposing risk factors:
o Trauma to cornea
o Contamination w/ organic material (gardners)
o Topical steroid use - Gardeners
- Immunocompromised
- Fewer inflammatory signs & symptoms in initial phase – can manifest self over many weeks
- Minimal conjunctival injection – less redness
- Filamentous fungus:
o Gray-white infiltrate w/ feathery margins
o May elevate corneal surface
o Satellite lesions may be present
o Endothelial plaque +/- hypopyon w/ rapid progression - Candida:
o Superficial white lesions
Describe the management for fungal keratitis?
o Very difficult
o Initial tx probably for bacterial keratitis until diagnosis proven by biopsy
o Antifungals:
Amphoteracin B
Fluconazole
Itraconazole
Ketoconazole
Clotrimazole
Describe acanthamoebic keratitis?
- Protozoa
- Commonly associated w/ CL wear & swimming
- Severe pain disproportionate to signs
- Initial punctate keratopathy or dendrite
- Ring ulcer – develops in later stages
- Diagnosed by corneal scrape
- Often diagnosed late
- Suspected if non-responding to unconventional bacterial keratitis therapy
- Management:
o Have suspicion for acanthamoeba if see px who is not responding to conventional bacterial keratitis tx
o Urgent referral – do not delay
o Stop CL wear & bring w/ solution for culture
o Corneal scrape
o Topical amoebicides
o Topical steroids – ABSOLUTE NOT TO BEGIN WITH – wait at least a fortnight if not a month to control the infectious part before treating inflammatory part
Describe neurotrophic keratitis and the three stages?
- Reduced corneal sensation resulting in corneal ulceration
- Cornea needs good nerve supply for epithelium to continually regenerate – if nerve supply compromised epithelium can break down leads to ulceration & non-healing defects
- Can be due to HSV keratitis and lots of other infectious/metabolic causes
- Stage 1:
o Early stage
o Punctate corneal epithelium (Gaule spots)
o Superficial vascularization
o Stromal scarring
o Decreased tear break up time
o Increased tear mucus viscosity
o Epithelial hyperplasia and irregularity
o Hyperplastic precorneal membrane
o Staining of palpebral conjunctiva with Rose Bengal - Stage 2:
o Epithelial defect, usually in superior half of cornea
o Smooth and rolled epithelial defect edges
o Surrounding rim of loose epithelium
o Stromal oedema
o Anterior chamber inflammation - Stage 3:
o Corneal ulcer
o Stromal melting
o Perforation
o Difficult to treat
