Cornea: Keratitis

Question 1

How do you tell which type of keratitis it is?

Answer 1

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)

Question 2

Describe marginal keratitis & its treatment?

Answer 2

• 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

Question 3

Describe Superficial Punctate Keratitis?

Answer 3

• 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

Question 4

Describe the most common ways that ocular surface infections are spread?

Answer 4

• 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

Question 5

Describe molluscum contagiosum?

Answer 5

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

Question 6

Describe Peripheral keratitis?

Answer 6

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

Question 7

Describe herpes simplex virus (HSV) keratitis?

Answer 7

• 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

Question 8

Describe the management for HSV keratitis?

Answer 8

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

Question 9

Describe HSV Disciform keratitis?

Answer 9

• Endotheliitis
• Often has circular lesion (disc)
• Associated uveitis

Question 10

Describe HSV Stromal keratitis?

Answer 10

• 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

Question 11

Describe Herpes Zoster Ophthalmicus (HZO)?

Answer 11

• 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

Question 12

Describe the management for Herpes Zoster Ophthalmicus?

Answer 12

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

Question 13

Compare the epithelial changes of HSK vs VZV?

Answer 13

• 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

Question 14

Describe bacterial keratitis? & ulcers?

Answer 14

• 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

Question 15

Describe CL related keratopathy management?

Answer 15

• 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

Question 16

Describe the clinical presentation of bacterial keratitis?

Answer 16

• Rapid onset of pain
• Conjunctival injection
• Photophobia
• Decreased vision – if ulcer is on visual axis
• Rate of progression depends on virulence of organism

Question 17

Describe the clinical presentation of pseudomonas bacterial keratitis?

Answer 17

• 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

Question 18

What is the management for non-vision threatening bacterial keratitis?

Answer 18

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

Question 19

What is the management for vision threatening bacterial keratitis?

Answer 19

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

Question 20

What are the signs of improvement in bacterial keratitis?

Answer 20

• 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

Question 21

Describe fungal keratitis?

Answer 21

• 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

Question 22

Describe the management for fungal keratitis?

Answer 22

o Very difficult
o Initial tx probably for bacterial keratitis until diagnosis proven by biopsy
o Antifungals:
 Amphoteracin B
 Fluconazole
 Itraconazole
 Ketoconazole
 Clotrimazole

Question 23

Describe acanthamoebic keratitis?

Answer 23

• 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

Question 24

Describe neurotrophic keratitis and the three stages?

Answer 24

• 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