Varicella Zoster Virus Myositis Mimicking Cranial Nerve VI Palsy in Herpes Zoster Ophthalmicus
Victoria Tram Nguyen1, Kevin Littrell2, Tse Chiang Chen3, Elizabeth Crabtree-Hartman4
1San Antonio Uniformed Services Health Education Consortium (SAUSHEC), 2George Washington University, 3Tulane School of Medicine, 4Tulane University School of Medicine
Objective:
To highlight Varicella Zoster Virus Myositis as a potential mimicker of cranial VI palsy in Herpes Zoster Ophthalmicus
Background:
Cranial nerve VI (abducens nerve) palsy causes impaired eye abduction and horizontal double vision. Etiologies include trauma, ischemic neuropathy, stroke, inflammatory disorders, and infections. Muscular and viral causes mimicking this condition are uncommon. Varicella zoster virus (VZV), a highly contagious alpha-herpesvirus, causes chickenpox and shingles. Myopathic manifestations are less common.
Design/Methods:
N/A
Results:

A 46-year-old male with a history of sleep apnea and hypertension presented to the emergency department with a 4-day history of a left facial rash. Initially suspected as an allergic reaction, the rash evolved into painful vesicles, prompting further medical attention. Examination revealed a vesicular rash on the left forehead and eyelid, elevated blood pressure, leading to a diagnosis of herpes zoster ophthalmicus (HZO). The patient was noted to have disconjugate gaze, prompting Neurology consultation. Examination by Neurology disclosed decreased abduction of the left eye with no accompanying abnormal cranial nerve findings and no long tract signs, consistent with isolated CN VI palsy. Brain and orbit MRI with and without contrast revealed asymmetric enhancement of the left optic nerve sheath and enlargement and enhancement of the left extraocular muscles. No acute infarcts, hemorrhages, or intracranial abnormalities were identified. Laboratory tests showed triglyceridemia, but was otherwise unremarkable. The patient was diagnosed with infectious optic neuritis and left extraocular muscle inflammation secondary to HZO. Treatment with IV acyclovir for ten days resulted in symptom improvement, including resolution of the rash and diplopia.

Conclusions:
VZV, a highly contagious alphaherpesvirus, may provoke ocular manifestations such as HZO. Although VZV rarely induces myositis, involvement of the extraocular muscles is unusual. The use of MRI with contrast for brain and orbit imaging can facilitate diagnosis and differentiate between cranial nerve VI palsy and viral myositis.
10.1212/WNL.0000000000204902