Orbiting a Diagnosis

A 75 -year-old male with a history of chronic/small lymphocytic leukemia (CLL/SLL) presented for one day of left retro-orbital headache, painful eye movements, eyelid swelling, and diplopia. One week prior, his WBC count was 39.9 K/uL with 86% lymphocytes. Three days prior to presentation, the patient was prescribed amoxicillin/clavulanate for nasal congestion and clear drainage. Review of systems revealed ~20lb weight loss, fatigue, and chronic "sinus pressure" for the preceding 2 months, and was negative for fever, dental/facial surgery, or tooth pain. Eye examination revealed visual acuities of 20/20 OD, 20/25 OS, with slight dyschromatopsia OS. There was mild, diffuse limitation and pain with eye movements OS, and moderate upper and lower left eyelid edema. The anterior, posterior, and fundus examinations were unremarkable. CT head demonstrated intraconal stranding of the left orbit without brain or sinus abnormalities (Figure 1). The patient was admitted, and IV vancomycin and ceftriaxone were initiated for presumed orbital cellulitis. On hospital day 1, the patient's visual acuity decreased to 20/40-1 OS, with worsening dyschromatopsia and a new left rAPD. Funduscopy revealed development of left optic disc edema with peripapillary retinal folds (Figure 2). MRI of the brain demonstrated bilateral, asymmetric thickening of the optic nerves with enhancement of the optic nerve sheaths on the left greater than the right. Abnormal enhancement was also noted along the bilateral inferomedial frontal lobes and surrounding the bilateral olfactory bulbs and left foramen rotundum. (Figure 3). A workup for optic perineuritis was initiated