LAUSR

O ptic perineuritis denotes inflammation of the optic nerve sheath with sparing of axons and is usually associated with infectious and inflammatory etiologies. We present a rare case of biopsy-proven giant cell arteritis (GCA) causing bilateral optic perineuritis and inflammation of multiple branches of descending aorta raising the possibility that Takayasu arteritis (TA) and GCA are the spectrum of the same disease. A 60-year-old healthy Eritrean-Canadian man developed left-sided headache. He was seen by his family physician, empirically diagnosed with sinusitis and completed 2 courses of oral antibiotics without improvement. One month later, he noticed blurred vision in the right eye. He was also fatigued, lost some weight, and noticed that chewing became painful for him. On examination, central acuity was 20/20 in each eye, there was mild right relative afferent pupillary defect, and right optic nerve head appeared mildly elevated and pale with several peripapillary cotton wool spots (Fig. 1A). Humphrey visual fields (24-2 algorithm) demonstrated right inferior altitudinal defect (Fig. 1B). Erythrocyte sedimentation rate was 128 mm/h and C-reactive protein 91 mg/L (normal less than 9) with a relative thrombocytosis of 484,000 cells/mL. Empiric treatment with three-day course of intravenous (IV) methylprednisolone 1 g daily commenced. MRI of the brain and orbits demonstrated bilateral intraorbital optic nerve sheath enhancement with mild orbital fat stranding (Fig. 2A) with sparing of the optic nerve axons. Computed tomography (CT) of the abdomen revealed circumferential wall thickening of the infrarenal abdominal aorta suspicious for vasculitis. CT angiography of the chest further confirmed segmental thickening of the descending thoracic aorta and unilateral proximal superior femoral artery, as well as circumferential thickening of the infrarenal aorta and both common iliac arteries (Fig. 2B). Inflammatory and infectious screen including ANA, ANCA, HIV, syphilis, and hepatitis C virus serologies were unrevealing. A right temporal artery biopsy revealed active granulomatous arteritis with inflammation present mainly in the media with some minor spillover into the intima and adventitia. Disruption of the internal elastic lamina by the inflammatory process was noted. After treatment with IV prednisone, patient was switched to oral prednisone 60 mg daily as well as methotrexate 25 mg daily. When reassessed 3 months after the initial presentation, visual acuity remained stable and all systemic symptoms were resolved.