A previously healthy 10-year-old girl, presented with a 1-week history of holocranial headache, mostly affecting the frontotemporal area, coupled with photophobia, phonophobia and two episodes of vomiting. She also reported pain while looking downward and double vision when looking upward to the left. There was no fever, motor or sensory impairments or seizures. Upon admission, she exhibited left eye ptosis and convergent strabismus in the left eye. She also had difficulty in the upward left eye movement and experienced pain during downward left eye movement. She mentioned double vision when looking straight, upward and to the left, which resolved upon closing each eye individually. Pupils were isochoric and equally responsive to light. There were no other neurological signs. Furthermore, she didn’t have conjunctival injection or chemosis, and the funduscopic examination was normal.
Blood tests had no signs of acute inflammation, elevated sedimentation rate, hyperuricemia, elevated lactate dehydrogenase or peripheral blast cells. Thyroid function was normal. Sarcoidosis was excluded (normal angiotensin-converting enzyme and chest radiograph). Immunological studies showed negative results for rheumatoid factor, antinuclear antibodies, anti-DNAds antibodies and HLA-B27. Infectious study showed positive IgG for CMV, EBV, VZV and
Mycoplasma pneumonia, but without positive IgM.
Borrelia burgdorferi IgM and IgG were both negative. HIV was negative. Magnetic resonance imaging (MRI) displayed thickening of the superior rectus muscle, hyperintensity on T2-weighted images, and enhancement with gadolinium injection, without areas of diffusion restriction. Cranial MRI was normal.
Figure 1. a) MRI T2 Short tau inversion recovery (STIR), coronal view; b) MRI T1 fat-suppressed (FS), after intravenous injection of gadolinium, coronal view. MRI shows thickening of the superior rectus muscle, hyperintensity on T2-weighted images and enhancement with gadolinium injection (red arrows).
What is the diagnosis?