ISCHEMIC OPTIC NEUROPATHY ASSOCIATED WITH INTERNAL CAROTID-ARTERY DISSECTION

Background: Ischemic optic neuropathy (ION) is an infarction of the an terior or, less frequently, posterior part of the optic nerve, usually due to a disease of small arteries supplying the optic nerve. Carotid stenosis or occlusions are rare causes, and among them, carotid disse ctions have been so far reported in only 5 cases. Methods: We describe 4 patients with ION (2 anterior and 2 posterior) due to internal caro tid artery dissection of a consecutive series of 110 patients with int ernal carotid artery dissection (3.6%). Results: None of the patients had signs of central retinal artery occlusion or ischemic ocular syndr ome. Ischemic optic neuropathy occurred after a mean of 5.3 days (rang e, 3-8 days) following the first symptom, which was headache in 1 pati ent, transient monocular blindness in 2, and hemispheric transient isc hemic attack in 1. One patient had associated Horner syndrome, and 2 h ad severe ipsilateral headache and orbital pain. None of the patients developed a cerebral infarction. These features differ from those obse rved in ''classic'' nonarteritic anterior ION and might therefore poin t to carotid dissection. Conclusion: Ischemic optic neuropathy may occ ur as an early sign of carotid dissection: young age, previous transie nt monocular blindness, an association with pain, Horner syndrome, or hemispheric transient ischemic attacks are suggestive of this cause an d should prompt confirmatory investigations.