HERPES- SIMPLEX CORNEAL ULCER
HERPES- SIMPLEX CORNEAL ULCER (Herpes simplex keratitis)
- Most of the ocular infection are caused by HSV-1 except in neonates.
- Eye infection can be caused by HSV-2 through infected genitalia of mother.
Ocular involvement by HSV may occur in 2 forms:
A) Primary herpes:
- Unilateral blepharoconjunctivitis
- Characterized by vesicles on the skin of lids, follicular conjunctivitis
B) Recurrent ocular herpes:
- Recurrent disease may involve any or all layers of the cornea.
Recurrent herpatic keratitis is divided into:
1. Epithelial keratitis: Manifestation of epithelial keratitis include:
i) Corneal vasicles: Vesicles coalesce & erupt to form dendritic or geographic ulcer.
ii) Superficial punctate keratitis
ii) Dendritic ulcer:
- Most common presentation
- Typical lesion of herpes keratitis
- There is an associated marked diminution of sensation.
iv) Geographic ulcer (amoeboid ulcer)
2. Stromal keratitis: Stromal keratitis may be of two types:
i) Disciform keratitis:
- Due to damage to endothelial cells as a result of hypersensitivity reaction to HSV antigen.
ii) Diffuse stromal necrotic keratitis:
- Caused by active viral & tissue destruction
3. Metaherpatic keratitis (epithelial sterile trophic ulceration):
- Not an active disease.
- Mechanical healing problem at the site of previous herpetic ulcer.
TREATMENT
Depends upon type of keratitis:
1. Primary ocular herpes:
- Usually self limited.
- Treatment is recommended to limit corneal involvement.
- Topical Trifluridine or Vidarabine, or Acyclovir can be used.
- A cycloplegic (atropine) may be added for comfort from ciliary spasm.
2. Recurrent ocular herpes:
i) Epithelial keratitis (Dendritic, geographic ulcer, punctate keratitis):
- Topical antivirals (Acyclovir, Ganciclovir, Trifluorothymidine, Idoxuridine) are drugs of choice.
- Topical steroids are contraindicated.
- Debridement of infected epithelium is also done.
ii) Stromal keratitis (Disciform or diffuse stromal necrotic)
- Topical corticosteroids along with topical or oral antiviral drugs.
iii) Metaherpatic keratitis:
- Neither topical steroids nor antivirals are used.
- Treatment is aimed at promoting healing by use of lubricants (artificial tears), bandage soft contact lens & lid closure (tarsorrhaphy).
Exam Important
- Dendritic ulcer is seen in Herpes simplex keratitis.
- Disciform herpatic keratitis involves Endothelium.
- Clinical presentation of herpes simplex keratitis is Diffuse stromal necrotic keratitis, Punctate epithelial keratitis & Disciform keratitis.
- Corneal sensation is lost in Herpes simplex.
- Ameboid ulcer is a feature of Herpetic corneal ulcer.
- Drug contraindicated in dendritic keratitis is Dexamethasone.
- Herpetic keratitis is treated by Idoxuridine.
- Topical steroids can be used in Disciform keratitis.
