Cranial nerve palsy in spontaneous dissection of the extracranial internal carotid artery.

Cranial nerve palsy was present in 23 of 190 consecutive adult patients (12%) with spontaneous dissection of the extracranial internal carotid artery. Ten patients (5.2%) had a syndrome of lower cranial nerve palsies (with invariable involvement of cranial nerve XII with or without additional involvement of cranial nerves XI, X, and IX), seven (3.7%) had palsy of cranial nerve V, and five (2.6%) had a syndrome of ocular motor palsies. Palsy of cranial nerve VIII and ischemic optic neuropathy occurred in one patient each. Three patients had dysgeusia without other cranial nerve involvement, presumably due to involvement of the chorda tympani nerve. Headache or face pain (often unilateral) was present in 83% of patients. Other associated manifestations were cerebral ischemic symptoms, bruits, or oculosympathetic palsy. In one patient, cranial nerve palsy was the only manifestation of internal carotid artery dissection, and in another patient, the disease presented only as a palsy of cranial nerve XII and oculosympathetic palsy. In six patients, a syndrome of hemicrania and ipsilateral cranial nerve palsy was the sole manifestation of internal carotid artery dissection. Cranial nerve palsy is not rare in internal carotid artery dissection. Compression or stretching of the nerve by the expanded artery may explain some but not all of the palsies. An alternative mechanism is likely interruption of the nutrient vessels supplying the nerve.