Lower cranial nerve palsy produced by internal carotid artery dilatation. Report of two cases

We report two cases of lower cranial nerve palsies (XII in case 1, IX-X-XII in case 2) associated with abnormalities of the internal carotid artery at the base of the skull. In case 1 a limited dissection of the carotid wall produced both paresis of the hypoglossal nerve and Horners syndrome by compression of the nerve trunk against the base of the skull and stretching of the periarterial sympathetic fibres respectively. In case 2 we speculate that a narrow angled kinking of the internal carotid artery may have damaged cranial nerves IX, X and XII by interfering with the blood supply to the nerve trunks. In both cases the outcome was favorable with almost complete regression of the initial symptoms. We conclude that the association between lower cranial nerve disturbances and internal carotid artery abnormalities is probably more common than was thought. We suggest that the pathogenesis of the damage to the cranial nerves may differ from one case to the next.