Kristin M. Hammersmith
BASICS
DESCRIPTION
• Acute, painful, vesicular eruption distributed along the ophthalmic branch of the trigeminal nerve (1).
• Ocular inflammation without characteristic rash: Zoster sine herpete (2).
EPIDEMIOLOGY
Incidence
• 200,000 new cases per year in the US.
• 1% life time risk (3).
RISK FACTORS
• Increasing age.
• Immune compromise (i.e., HIV, cancer, immunosuppression) (4).
GENERAL PREVENTION
• CDC recommendation (2008)—routine vaccination of all individuals 60 years or older with Varicella Zoster Vaccination (Zostavax®), including those with prior history of herpes zoster or chronic medical conditions.
• The vaccine is not licensed for the treatment of acute HZ or post herpetic neuralgia (PHN), or for the prevention of HZ in patients aged younger than 60 years (5).
PATHOPHYSIOLOGY
• Reactivation of latent virus from trigeminal ganglia with viremia and spread of virus from sensory axons to skin.
• Age-related decline in varicella-zoster virus specific cell mediated immunity increases susceptibility to viremia (5).
DIAGNOSIS
HISTORY
• Painful vesicular eruption in a single dermatome.
• Fever, malaise, headache, and pain in the affected dermatome.
• Affective disorder: Anorexia, lassitude, mood changes, antisocial behavior, depression, and insomnia (6).
PHYSICAL EXAM
• Rash involving the V1 dermatome evolving from an erythematous lesion with macules, papules and vesicles with pustules and crusts developing subsequently.
• Slit-lamp examination.
– Early:
– Eyelid: Hyperemia, edema, ptosis.
– Conjunctiva: Hyperemia, petechial hemorrhages, vesicles, pseudodendrites, papillae, follicles, pseudomembranes.
– Sclera/episclera: Limbal vasculitis, sclerokeratitis, posterior scleritis.
– Cornea:
– Epithelium: Pseudodendrites, punctate epithelial keratitis.
– Stroma: Nummular stromal keratitis, disciform keratitis (7).
– Iris/uvea: Segmental iris edema, granulomatous keratouveitis with keratic precipitates (8), secondary glaucoma (9).
– Retina/optic nerve: Retinal perivasculitis, ischemic optic neuritis, necrotizing retinopathy.
– Late (1 month after rash):
Eyelid: Cicatricial entropion/ectropion, trichiasis.
Conjunctiva: Hyperemia, pseudomembranes.
Sclera/episclera: Limbal vasculitis, sclerokeratitis, posterior scleritis.
Cornea:
Epithelium: Delayed pseudodendrites (mucous plaque keratitis), punctate epithelial keratitis, neurotrophic ulceration, band keratopathy (10).
Stroma: Nummular stromal keratitis, disciform keratitis, lipid deposition, anterior and posterior stromal scarring, chronic edema (7).
Iris/Uvea: Segmental iris atrophy, granulomatous keratouveitis with KP, secondary glaucoma.
Retina: Acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN).
• Neuroophthalmic examination.
– Extraocular muscles: Transient EOM palsy and diplopia (11).
– Cranial nerves: CN III, IV, or VI can be involved indicating vasculitis within the orbital apex (orbital apex syndrome) or brainstem dysfunction (12).
– Acute pain: Characterized as lancinating, burning, aching, and/or itching.
– Post-herpetic neuralgia (PHN)—pain lasting more than 1 month after disease onset. Characterized as constant or intermittent aching or burning, sudden lancinating pain, allodynia (pain from nonpainful stimuli), and/or a constant or intermittent itch (13).
DIAGNOSTIC TESTS & INTERPRETATION
Lab
No laboratory work up is necessary unless there is a high index of suspicion for HIV.
Imaging
Initial approach
Slit-lamp examination including intraocular pressure assessment, corneal sensation, and dilated funduscopic examination.
Follow-up & special considerations
• Starting oral antiviral therapy shortens the duration of acute pain, virus shedding, rash, acute, and late-onset anterior segment complications, and the incidence and severity of PHN (12).
• Depending on severity of ocular inflammation, patient should be re-evaluated within 5–7 days and frequency of follow-up visits should be dictated by severity of slit-lamp findings.
ALERT
Treatment with valacyclovir in severe immunocompromise has been associated with thrombocytopenic purpura/hemolytic uremic syndrome and is therefore not FDA approved for use in this subset of patients.
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