The Path of Least Resistance: Over the Nose, Into the Orbit, and Around the Globe

A 45 year-old man presented emergently with progressively worsening blurred vision, oblique binocular diplopia, photophobia, and dyschromatopsia in the left eye for 4 months. He reported swelling around the left eye, unintentional weight loss of 25 pounds, and presence of cervical lymph nodes for several months. Medical history included hypertension, diabetes, asthma with recent exacerbations, and seasonal allergies. He was seen by ophthalmology whose examination of the left eye revealed 3+ rAPD, slight proptosis, -4 abduction deficit, normal color vision via Ishihara color plate testing, and Frisen-like grade 3 disc edema with mild temporal peripapillary atrophy. Contrasted MRI brain & orbits showed enlargement and contrast enhancement of the left lateral rectus muscle, optic nerve sheath, and cavernous sinus. Serum studies were largely unremarkable including TSH, ANCA, ACE, lysozyme, IL2, IL6, MOG/NMO antibodies, thyroid antibodies, immunoglobulins, SPEP, syphilis, Lyme, and TB. ANA was positive with titer 1:320. CSF studies showed normal protein, cell count, and RBCs; elevated glucose (consistent with hyperglycemia); and unremarkable IgG index, ACE, VDRL, and fungal studies. He was started on prednisone 1 mg/kg daily with significant improvement in his ocular symptoms including resolution of blurred vision with acuity of 20/20-2, 1+ rAPD, and -1 abduction and supraduction deficits causing residual diplopia on extreme left gaze. There was improvement of edema around the orbit and optic disc of the left eye. Repeat MRI brain & orbits showed disease improvement. A diagnostic procedure was performed.