Ophtalmoplégie extrinsèque pure douloureuse du nerf moteur oculaire commun révélant un anévrysme de la carotide

Introduction. In third cranial nerve palsy, the lack of mydriasis evokes a noncompressive mechanism. Case report. We report a case of a slightly painful, pure extrinsic third-nerve palsy, complete except for the partial ptosis secondary to the compression by an intracavernous carotid aneurysm. Percutaneous endovascular embolization was followed by complete regression of the palsy within 4 weeks. The pupil may have been spared by the mechanism of compression after the separation of the pupillomotor and extrinsic fibers or the ischemia of the third nerve by its arterial trunk lesion. Conclusion. This case report underlines that brain radiological explorations are necessary in some third-nerve pupil-sparing palsies.