Case 13 - Cornea, external disease, and anterior segment
33-year-old man - Recurrent unilateral left eye irritation x 4 years - Right eye always spared
A 33-year-old man has had recurrent episodes of irritation in his left eye for 4 years. His right eye remains free. Episodes last 5-6 days with foreign body sensation, photophobia, and tearing. The lesion shown is on the corneal surface after fluorescein application.
DENDRITIC ULCER - branching, linear epithelial defect with TERMINAL BULBS at each branch end. Fluorescein pools in the defect (stains green). Terminal bulbs = pathognomonic for HSV (distinguishes from HZO pseudodendrites which have no true epithelial erosion). Rose bengal stains live HSV-infected cells at dendrite edges.
Topical: Trifluridine 1% (q2h x 14d, ~95% healing), Ganciclovir 0.15% gel (5x/d, better tolerated), Acyclovir 3% ointment. Oral: Acyclovir 400 mg 5x/d or Valacyclovir 500 mg TID. Long-term prophylaxis: acyclovir 400 mg BID -> 45% down in recurrence (HEDS trial). Indicated after >=2 episodes/year or stromal involvement.
Herpes Simplex Keratitis (HSK) - Epithelial/Dendritic type. #1 infectious cause of corneal blindness in developed countries. Recurrent unilateral episodes are characteristic. DDx: HZO pseudodendrites (no terminal bulbs), Acanthamoeba (CL wearer, radial keratoneuritis), Thygeson's SPK (bilateral, no dendrites).
TOPICAL CORTICOSTEROIDS ABSOLUTELY CONTRAINDICATED in active epithelial HSK - suppress viral clearance -> geographic ulcer -> perforation. (Steroids WITH antiviral cover ARE used for stromal HSK and iridocyclitis) Also avoid topical NSAIDs (impair healing) and contact lens wear during active episodes.
NEVER give topical steroids for a red eye without ruling out HSV epithelial keratitis - always stain with fluorescein first. Terminal bulbs at dendrite branch ends = HSV. HEDS trials: prophylactic acyclovir down recurrence 45%; steroids alone worsen epithelial HSK; steroids + antivirals help stromal disease. Recurrent disease causes progressive stromal scarring -> potential corneal transplant.
Findings Treatment DENDRITIC ULCER - branching, linear epithelial defect with TERMINAL BULBS at each Topical: Trifluridine 1% (q2h x 14d, ~95% healing), Ganciclovir 0.15% gel (5x/d, better branch end. Fluorescein pools in the defect (stains green). Terminal bulbs = pathognomonic tolerated), Acyclovir 3% ointment. Oral: Acyclovir 400 mg 5x/d or Valacyclovir 500 mg TID. for HSV (distinguishes from HZO pseudodendrites which have no true epithelial erosion). Long-term prophylaxis: acyclovir 400 mg BID -> 45% down in recurrence (HEDS trial). Indicated Rose bengal stains live HSV-infected cells at dendrite edges. after >=2 episodes/year or stromal involvement. Diagnosis Drugs to AVOID Herpes Simplex Keratitis (HSK) - Epithelial/Dendritic type. #1 infectious cause of corneal TOPICAL CORTICOSTEROIDS ABSOLUTELY CONTRAINDICATED in active epithelial HSK - blindness in developed countries. Recurrent unilateral episodes are characteristic. DDx: suppress viral clearance -> geographic ulcer -> perforation. (Steroids WITH antiviral cover HZO pseudodendrites (no terminal bulbs), Acanthamoeba (CL wearer, radial ARE used for stromal HSK and iridocyclitis) Also avoid topical NSAIDs (impair healing) and keratoneuritis), Thygeson's SPK (bilateral, no dendrites). contact lens wear during active episodes. TEACHING PEARL NEVER give topical steroids for a red eye without ruling out HSV epithelial keratitis - always stain with fluorescein first. Terminal bulbs at dendrite branch ends = HSV. HEDS trials: prophylactic acyclovir down recurrence 45%; steroids alone worsen epithelial HSK; steroids + antivirals help stromal disease. Recurrent disease causes progressive stromal scarring -> potential corneal transplant.
