Presentation
Acute headache behind left eye.
Patient Data
No intracranial abnormality is detected. There is subtle increase in the size of all the left orbital rectus muscles compared to the right without obvious stranding of the adjacent fat. The pre-septal tissues appear normal. The appearance suggests left orbital myositis of unclear etiology.
Orbital MRI was performed 2 days after the CT.
The left orbital rectus muscles are edematous and show increased enhancement compared to the contralateral side. Since the CT study, pre-septal edema and enhancement of subcutaneous tissues have developed.
Case Discussion
Clinically, the patient went on to develop a vesicular rash in the in V1 distribution. A diagnosis of herpes zoster ophthalmicus was subsequently confirmed.
A case of herpes zoster ophthalmicus with orbital extra-ocular myositis preceding the skin rash and pre-septal inflammation. This delay between myositis and onset of rash has been noted often in the medical literature, and therefore evolving herpes zoster ophthalmicus should be considered in the differential diagnosis for acute unilateral orbital myositis, even in the absence of any rash.