Ophthalmic herpes zoster

Opstelten W, Zaal MJW Managing ophthalmic herpes zoster in primary care. BJM 2005 331 147-151. 

A 59-year-old woman on hemodialysis was treated with oral aciclovir 200 mg/day for ophthalmic Herpes zoster. After a few days, an ophthalmic aciclovir cream was started (one application every 6 hours) because of ipsi-lateral Herpes keratitis. After 1 week of combined oral and topical treatment, she became confused, with dysarthria and audiovisual hallucinations. Aciclovir was withdrawn and hemodialysis was initiated. Complete resolution of symptoms was achieved after three hemodialysis sessions in 3 days. Aciclovir plasma concentrations before hemodialysis were high (45 pmol/l) and fell rapidly during hemodialysis. 

Infection risk An immunocompetent 3-year-old girl developed encephalitis and ophthalmic herpes zoster 20 months after immunization with varicella zoster virus vaccine [29 ]. Molecular analysis confirmed that the vaccine strain was the causative agent and this was therefore a between-the-eyes adverse reaction of type 4 [30 ]. After an intravenous course of aciclovir, the child made a full recovery with no neurological sequelae. 

Ophthalmic disorders Decreased inflammation Chorioretinitis, conjunctivitis, herpes zoster ophthalmicus, iridocyclitis, keratitis, optic neuritis... 

When reactivation occurs, the virus passes along the sensory nerve and erupts on the tissue innervated by that nerve (dermatome).The thoracic ganglion ranks first and the trigeminal ganglion second in order of frequency of zoster involvement. The ophthalmic division of the trigeminal ganglion is involved 20 times more frequently than the maxillary and mandibular branches and is known as herpes zoster ophthalmicus (HZO). 

In immunocompetent adults with herpes zoster of 3 days duration or less, famciclovir (500 mg three times a day for 10 days) is at least as effective as acyclovir (800 mg five times daily) in reducing healing time and zoster-associated pain, particularly in those 50 years of age and older. Famciclovir is comparable with valacyclovir in treating zoster and reducing associated pain in older adults. Famciclovir (500 mg three times a day for 7 to 10 days) also is comparable with high-dose oral acyclovir in treating zoster in immunocompromised patients and in those with ophthalmic zoster. 

Vidarabine, an antiviral agent (10 to 15 mg/kg/day for 5 to 10 days), is indicated in the treatment of herpes simplex virus encephalitis, neonatal herpes simplex virus infections, and herpes zoster in immunosuppressed patients. In addition, vidarabine (ophthalmic ointment 3% vidarabine monohydrate [equivalent to 2.8% vidarabine]) is indicated in the treatment of acute keratoconjunctivitis and recurrent epithelial keratitis due to herpes simplex virus types 1 and 2, or superficial keratitis caused by herpes simplex virus that has not responded to topical idoxuridine or when toxic or hypersensitivity reactions to idoxuridine have occurred. 

Herpes zoster ophthalmicus is a latent reactivation of a varicella zoster infection in the first division of the trigeminal cranial nerve. Systemic acyclovir, valacyclovir, and famciclovir te. effective in reducing the severity and complications of herpes zoster ophthalmicus. Currently, there are no ophthalmic preparations of acyclovir approved by the FDA, although an ophthalmic ointment is available for investigational use. 

Vidarabine is used mainly in human HSV-1 and HSV-2 encephalitis, decreasing the mortality rate from 70 to 30%. Whitley et al. (57) reported that early vidarabine therapy is helpful in controlling complications of localized or disseminated herpes zoster in immunocompromised patients. Vidarabine also is useful in neonatal herpes labialis or genitalis, vaccinia virus, adenovirus, RNA viruses, papovavirus, CMV, and smallpox virus infections. Given the efficacy of vidarabine in certain viral infections, the U.S. FDA approved a 3% ointment for the treatment of herpes simplex keratoconjunctivitis and recurrent epithelial keratitis, and a 2% IV injection for the treatment of herpes simplex encephalitis and herpes zoster infections (Table 43.3). A topical ophthalmic preparation of vidarabine is useful in herpes simplex keratitis but shows little promise in herpes simplex labialis or genitalis. The monophosphate esters of vidarabine are more water-soluble and can be used in smaller volumes and even intramuscularly. These esters are under clinical investigation for the treatment of hepatitis B, systemic and cutaneous herpes simplex, and herpes zoster virus infections in immunocompromised patients. 

If the herpes zoster occurs near or in the eyes, it could cause blindness and is considered an ophthalmic emergency. 

A link between ophthalmic complications and the zoster vaccine has been proposed. An 86-year-old man, with previous herpes zoster ophthalmicus, developed anterior uveitis following administration of Zostavax . This was treated successfully with topical steroids [76 ]. 

Antiviral Efficacy and Clinical Use. Vidarabine (Vira-A) was the first systemic agent used to treat herpesvirus infections, including CMV, herpes simplex virus, and varicella-zoster virus.42 In the past, this drug was administered by continuous intravenous infusion to treat severe systemic infections caused by these viruses, but systemic use of vidarabine has been replaced by safer and less toxic agents. Vidarabine is currently used primarily to treat local viral infections of the eye (e.g., herpes simplex keratoconjunctivitis) it is applied topically by ophthalmic ointment to treat these infections. 

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