Horner's syndrome and headache due to carotid artery disease.

Horner's syndrome was accompanied by ipsilateral pain in the head, face, or neck in eight patients. In all cases angiography showed narrowing of the internal carotid artery in a pattern compatible with dissection within the arterial wall. In one patient in whom this diagnosis was substantiated by surgical exploration biopsy of the arterial wall showed changes typical of cystic medial necrosis. It is suggested that this clinical presentation constitutes a distinct syndrome.