[The value of orbit magnetic resonance imaging in the diagnosis of blindness caused by giant cell arteritis]. / Aportación de la resonancia magnética orbitaria al diagnóstico de la ceguera por arteritis de células gigantes.

INTRODUCTION: Giant cell arteritis (GCA) is a chronic vasculitis of middle-sized and large calibre vessels which occurs mainly in individuals aged over the age of 50. It chiefly affects the cranial branches of the arteries that originate in the aortic arch. Its most important characteristic symptoms include visual disorders, especially loss of sight; bilateral blindness, however, is infrequent. CASE REPORT: We describe the case of an 81-year-old female who visited because of sudden blindness and bilateral retroocular pain. The neurological exploration only revealed bilateral amaurosis, dilated pupils with the phenomenon of papillary escape, and no alterations to the ocular fundus. Laboratory tests showed a haemoglobin level of 12 mg/dL, ESR of 71 mm/hr and CRP of 2.3. Magnetic resonance imaging (MRI) and computerised tomography of the brain without intravenous contrast showed findings compatible with small vessel ischemic phenomena. Because a vasculitic process was suspected, orbit RMI was performed and revealed signal hyperintensity in the soft intraconal parts with respect to the extraocular muscles. A biopsy study of the left temporal artery was compatible with GCA. CONCLUSIONS: In cases of GCA with an atypical visual presentation, finding enhancement of the intraconal fat or of the optic nerve sheath in the RMI can support the suspicion of an arteritic process.