Viral Keratitis
CORNEAL DENDRITE
What else do you want to know
about this patient?
What would be your initial treatment?
Wilhelmus KR. Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis. Cochrane Database Syst Rev. 2010 Dec8;(12) 2
RISK FACTORS:REFRACTORY AND RECURRENT
3Mucci JJ, Utz VM, Galor A, Feuer W, Jeng BH. Recurrence rates of herpes simplex virus keratitis in contact lens and non-contact lens wearers. Eye Contact Lens. 2009 Jul;35(4):185-7.
• Why use others?
– valacyclovir (Valtrex)
– famciclovir (Famvir)
• Why not topicial trifluridine?
ORAL ANTIVIRALS
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Nguyen DQ, Srinivasan S, Hiscott P, Kaye SB. Thimerosal-induced limbal stem cell failure: report of a case and review of the literature.Eye Contact Lens. 2007 Jul;33(4):196-8.
Loutsch JM, Sainz B Jr, Marquart ME, Zheng X, Kesavan P, Higaki S, Hill JM, Tal-Singer R. Effect of famciclovir on herpes simplex virus type 1 corneal disease and establishment of latency in rabbits. Antimicrob Agents Chemother. 2001 Jul;45(7):2044-53.
Why do most ophthalmologists still use acyclovir as their oral agent of choice?
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Drug Treatment Prevention
Acyclovir 400mg 5 x day 400mg bid
Valacylovir 1000mg tid 500-1000mg daily
Famciclovir 250-500mg tid 250mg bid / 500mg daily
Cost of Oral Antivirals
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WHOLESALE COST Per Pill 1 month
Generic valacyclovir 500 mg tab $0.8475 $25.43 (500mg)
Generic famciclovir 500 mg tab $1.6906 $50.72
Generic acyclovir 400 mg tab $1.2700 $76.20 (800mg)
MARGINAL KERATITIS?
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• IV or oral suspension
• Long term prophylaxis:dose reviewed at least every 6 months (weight based!)
• Dose:
– Over 40kg – 400mg bid
– 30mg/kg/day divided q8h
CHILDREN
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HZV – HSV FACE OFF
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HSV HZV
Dendrite Ulcerated, terminal bulb Elevated, taper
Corneal sensation Variable Loss
IOP Rare elevation Trabeculitis
Live virus Yes YES
Antiviral Yes: viroptic 5-9xdayAcyclovir 400mg x 5
Yes: topical andFamvir 500 tid
Less / More More often multiple lesions, endotheliitis
More often epi defects, iris defects, diffuse haze
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STROMAL KERATITIS?
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The Answered Questions The Unanswered Questions Clinical Practice
Stromal keratitis improves with steroids (HEDS 1 SKN)
Would longer steroid duration / taper lead to less treatment failures?Would oral antiviral prophylaxis benefit?
Longer taper, oral antiviral coverage is used commonly, trend toward leaving long-term
Stromal keratitis patients on steroids and trifluridine don’t need acyclovir(HEDS 1 SKS)
What if the patient is not on trifluridine?
Oral antiviral is commonly substituted for topical antiviral
Acyclovir may help when added to steroid / topical antiviral treatment(HEDS 1 IRT)
Does it help? With trabeculitis, iritis, stromal keratitis, oral antiviral is commonly used
Addition of acyclovir to trifluridine in epithelial disease does not reduce the incidence of stromal keratitis (HEDS II)
Could acyclovir be used as an alternative to trifluridine?
Patients with first episode usually don’t receive oral acyclovir
Acyclovir 400mg bid prevents recurrent herpetic eye disease
Lower dose? Treatment duration?
6 to 12 months duration, other oral antivirals substituted
HOW DID WE GET HERE?
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NEUROTROPHIC ULCER V. PERSISTENT EPITHELIAL DEFECT
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• AAO guidelines:
– 5 minute soak:
• 70% ehtyl ethanol
• 1:10 sodium hypochlorite (bleach)
• Gloves / Isolation room / Avoid waiting room
• Avoid contact with surfaces / instruments / drops
DISINFECTION AND HYGIENE
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• Povidone-Iodine 0.5% QID + Dexamethasone 0.1% QID x 10 days
• Povidone-Iodine 5% wash?
• Gancilovir gel (special access)?
• The RPS Adeno Detector (Rapid Pathogen Screening)
• Mixed results in studies
ACUTE TREATMENT
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WHEN TO TREAT
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VISION
PAIN
SEVERE
• 9 patients (12 eyes) with 13month follow-up
• Steroid failures or “responders”
• Cyclosporine 1% BID
• Conclusion:– IOP normalized and reduced medications
– All patients stable (1/3) or improved (2/3)
– Severity of symptoms improved
– Trend of improved vision (2 lines)
TORONTO WESTERN HOSPITAL
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TAKE HOME POINTS
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• Be aggressive with epithelial defects in neurotrophiccorneas: punctal cautery, tarsorraphy, serum tears
• Don’t debride routine or high risk HSV dendrites
• Have your hospital stock viral cultures
• Oral and topical antiviral for HZV pseudo-dendrites
• Prevent and perhaps treat adenoviral conjunctivitis
• Zostavax: the vaccine for your cataract patients!
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• One million new episodes world-wide per year (epithelial keratitis), 5000 per year in Canada 0.014%
• Besides HSV-1, much less common causes of dendritic epithelial keratitis:
– HSV-2
– Varicella-zoster virus
– Co-infection with HSV-1 and human herpes virus 6
– Very rarely, cytomegalovirus, epstein-barr virus, or adenovirus
• Pseudodendrite: esp day 1 abrasion, exposure keratopathy, neurotrophic cornea (esp diabetic)
QUICK FACTS
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