We present a unique case of Herpes Zoster Ophthalmicus (HZO) complicated abducens nerve palsy

Primary varicella zoster viral infection remains dormant in the dorsal root ganglia until reactivation of the virus occurs, resulting in herpes zoster. HZO  involves the ophthalmic branch of the trigeminal nerve. A rare complication of HZO is simultaneous involvement of additional cranial nerves, such as the oculomotor and  abducens nerves.

A 72-year-old man with a medical history of poorly controlled diabetes and long-standing hypertension, presented with recurrence of a painful rash in the left opthalmic nerve distribution. Three weeks prior to presentation, he was diagnosed with HZO and completed 7/10 days of treatment with antiviral medication, with partial resolution and subsequent return of the rash. One week after the return of the rash, he developed diplopia, worse on left gaze. He was diagnosed with an abducens nerve palsy. Examination revealed waning raised vesicular and cicatricial lesions on the left forehead consistent with HZO. A prism cover test revealed abduction was restricted in the left eye.

An MRI Brain with and without contrast showed no acute infarction, hemorrhage, or abnormal intracranial enhancement. MRA Head and Neck was normal. He was prescribed intravenous acyclovir for 7 days and given gabapentin 600mg three times a day for severe neuropathic pain. His rash and neuropathic pain improved 1 week later. His diplopia improved over the next month.

We identified five cases in the literature of HZO with cranial nerve palsies. Of these, two  had neuroimaging findings. One case showed local inflammation of the muscle and orbit; the other had clinical symptoms of Horner’s syndrome with large artery involvement. We conclude that neuroimaging is unlikely to be helpful in HZO with isolated abducens nerve palsy. The role of steroids in treatment remains unclear and patients typically completely improve within 1 year.