aka Ophthalmology Befuddler 021
A 24 year-old medical student presents to the emergency department with 2 days of superficial left eye pain, mild redness, tearing and mild photophobia. She has a history of cold sores and has been stressed out by exams recently.
Slit lamp examination reveals this:
Prior to applying topical anesthesia, you checked corneal sensation, which was decreased.
Q1. What is the likely diagnosis?
Herpes simplex keratitis
The slit lamp shows a dendritic ulcer — classically this a thin, linear, branching epithelial ulceration with club-shaped terminal bulbs at the end of each branch.
Check out this excellent video demonstration of a dendritic ulcer at RootAtlas.com
Q2. What is the differential diagnosis of this type of lesion?
- HSV keratitis
- Acanthamoeba keratitis pseudodendrites
- Herpes zoster
- Recurrent corneal erosion (may be dendritiform if healing)
- Vaccinia keratitis (classically a complication of smallpox vaccination)
Q3. What should be assessed on history?
- Painful red eye, altered vision, foreign body sensation, photophobia, tearing; usually unilateral
- Skin (e.g., eyelid) vesicular rash may be present
- History of previous episodes of HSV (nasal, oral or ocular)
- Triggers? — may include fever, stress, trauma, immunosuppression or recent topical or steroid use, and ultraviolet light exposure
- History of contact lens use? (acanthamoebae may mimic HSV)
Q4. What features should be assessed on examination?
- Visual acuity — may be reduced due to a central corneal ulcer or tearing.
- External examination —
Skin — clear vesicles on an erythematous base that progress to crusting. They heal without scarring and cross dermatomes (usually localised to the eyelids when present, and be present bilateral).
Corneal sensation — may be decreased (check before applying topical anesthesia)
- Slit lamp examination —
Conjunctiva — acute unilateral follicular conjunctivitis +/- conjunctival dendrites +/- geographic ulcers.
dendritic keratitis — edges stain with rose bengal, central ulcer stains with fluorescein
Multiple other types lesions may occur:
geographic ulcers — a large, amoeba-shaped corneal ulcer with a dendritic edge),ghost ulcers (subepithelial scar
neurotrophic ulcers — associated with stromal melting and perforation
disciform keratitis — stromal edema with an intact epithelium
necrotizing interstitial keratitis — multiple or diffuse, whitish corneal stromal infiltrates with or without an epithelial defect
- Look for complications (see Q6)
Primary herpes simplex virus (HSV) infection is usually not apparent clinically, but may be present (especially in children) and may be devastating in neonates (e.g. CNS and multi-organ involvement).
Q5. What is the appropriate investigation and management?
The diagnosis is usually made clinically — although scrapings/ swabs of lesions may be used for confimation by viral culture.
Ophthalmology referral for assessment the next day.
Antiviral therapy —
- Start treatment with topical antivirals.
- consider topical aciclovir ointment 5 times daily for skin lesions (unproven)
- Trifluridine 1% drops (e.g., Viroptic) nine times per day or vidarabine 3% ointment (e.g., Vira-A) five times per day for conjunctival or corneal epithelial involvement
If corneal stromal disease or complications are present an ophthalmologist may initiate treatment with topical steroids and/ or systemic antivirals. Sometimes corneal debridement is required.
- Oral analgesia
- warm or cool soaks to skin lesions tds
- cycloplegics for AC involvement or photophobia
- treat complications
Q6. What are the possible complications of this condition?
- corneal scarring, melting or perforation
- uveitis and hypopyon
- permanent visual loss
- bacterial and fungal superinfection
- permanent visual loss
Q7. What should be suspected if the lesion fails to resolve over 2-3 weeks?
- topical antiviral toxicity (discontinue topical antivirals)
- neurotrophic ulcer
- Acanthamoeba keratitis (perform smears)
- Ehlers JP, Shah CP, Fenton GL, and Hoskins EN. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease (5th edition). Lippincott Williams & Wilkins, 2008.
- Jeff Mann’s EM Guidemaps. Red eye.
- Mahmood AR, Narang AT. Diagnosis and management of the acute red eye. Emerg Med Clin North Am. 2008 Feb;26(1):35-55, vi. PMID: 18249256.
- Marx JA, Hockberger R, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice, 7th edition (2009) Mosby, Inc. [mdconsult.com]
- NSW Statewide Opthalmology Service. Eye Emergency Manual — An illustrated Guide, 2007. [link to free pdf]