Herpes simplex Keratitis

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Findings

Epithelial keratitis

  • Punctate epithelial keratitis
  • Dendrites: fluorescein-positive branching epithelial ulcer, blunt ends with “terminal bulbs” 1 2
  • Geographica: larger epithelial defect with dendritic margins 3
  • Corneal sensation typically reduced

Neurotrophic ulcer

Stromal keratitis and endotheliitis

  • Immune reaction to viral antigens
  • Stromal opacities
  • Disciform (round) stromal/epithelial oedema above localised endotheliitis
  • typically with endothelial precipitates

Keratouveitis

  • See Anterior Uveitis
  • Definition
    • Keratouveitis = Anterior uveitis + keratitis
    • Uveitis anterior = without keratitis
  • Fine granulomatous endothelial precipitates, anterior chamber cells/flare, patchy iris atrophy, increased IOP (due to iridocyclitis)

Acute retinal necrosis (ARN)

Work-up

  • Medical history: previous episodes
  • Skin findings: vesicles in V1 suggest VZV, if only around the eye: HSV more likely
  • Slit lamp examination
    • Cornea: Epithelium: Dendrites? Ulcer? Stromal infiltrates? Stromal thinning? Corneal vascularisations? Precipitates? Corneal Sensation?
    • Anterior chamber: Cells? Flare?
    • Iris: Transilluminations? (HSV: diffuse; VZV: patchy) Posterior synechiae?
    • IOP: asymmetric? Elevated? Low?
      • CAVE: check corneal sensation first

Diagnosis

  • A smear is not mandatory if the clinical signs are typical (e.g. epithelial dendrites)
  • Corneal PCR swab or abrasion (e.g. with a Kimura spatula) in the area of the dendrites to remove loose epithelium, thereby reducing viral load.
  • If necessary, anterior chamber puncture for PCR: in recurrent episodes with uveitis in which HSV has never been detected.

Therapy

Epithelial keratitis

  • Virgan Gel (Gangciclovir) 5x/d
    • alternatively Zovirax ointment (Aciclovir) 5x/d
    • alternatively, Valtrex p.o. (Valaciclovir) 3x500mg daily (in case of surface problems or if application of ointments is difficult)
  • In case of large epithelial defects, consider prophylactic antibiotic treatment (e.g. Floxal SDU (Ofloxacin) 3x/d)
  • In case of keratouveitis (see Uveitis Anterior)
    • Consider Scopolamine gtt 2x/d to prevent posterior synechiae
    • Cauteously consider steroid drops (e.g. Pred forte gtt (Prednisolon) / Dexafree SDU (Dexamethason) depending on anterior chamber cells (CAVE: officially contraindicated in epithelial ulcers)
  • in case of non-healing epithelial defects
    • bacterial superinfection?
    • Acanthamoebae?
    • Poor compliance?
  • Epithelial toxicity of the drops? -> Switch to Valtrex p.o. (Valaciclovir) and intensive lubrification with drops without preservatives (e.g. Benzalkonium chloride).

Stromal keratitis and endotheliitis

  • Combination of local steroids and prophylactic Valtrex p.o. (Valaciclovir)
    • e.g. Pred forte gtt (Prednisolon) 4xtgl.
    • In case of epithelial defect, combined preparation with antibiotic, e.g. Tobradex gtt (Tobramycin + Dexamethason) 4x/d
  • Valtrex 3x500mg for 1-2 weeks, then reduce and treat prophylactically for several months (e.g. Valtrex (Valaciclovir) 2x250mg).
    • Reduce cautiously, depending on the frequency of recurrences, long-term therapy should be considered
      • CAVE: Check creatinine for long-term therapy

Neurotrophic ulcer

Acute retinal necrosis (ARN)

Follow-up

  • Within 1 week: Response to therapy?
  • Thereafter 1-2-weekly:
    • Assessment of: Epithelial defect? Depth of the ulcer? Vascularisation? Anterior chamber cells? IOP?
  • Reduce steroid drops slowly (over months to >1 year).
  • Long-term therapy with Valtrex (Valaciclovir) often necessary, evaluation of the minimum required dose (note down at which dose a relapse occurs!)

Sources