Spontaneous carotid dissection presenting lower cranial nerve palsies

Cranial nerve palsy in internal carotid artery (ICA) dissection occurs in 3--12% of all patients, but in 3% of these a syndrome of hemicranias and ipsilateral cranial nerve palsy is the sole manifestation of ICA dissection, and in 0.5% of cases there is only cranial nerve palsy without headache. We present two cases of lower cranial nerve palsy. The first patient, a 49-year-old woman, developed left eleventh and twelfth cranial nerve palsies and ipsilateral neck pain. The angio-RM showed an ICA dissection with stenosis of 50%, beginning about 2 cm before the carotid channel. The patient was treated with oral anticoagulant therapy and gradually improved, until complete clinical recovery. The second patient, a 38-year-old woman, presented right hemiparesis and neck pain. The left ICA dissection, beginning 2 cm distal to the bulb, was shown by ultrasound scanning of the carotid and confirmed by MR angiogram and angiography with lumen stenosis of 90%. Following hospitalisation, 20 days from the onset of symptoms, paresis of the left trapezius and sternocleidomastoideus muscles became evident. The patient was treated with oral anticoagulant therapy and only a slight right arm paresis was present at 10 months follow-up. Cranial nerve palsy is not rare in ICA dissection, and the lower cranial nerve palsies in various combinations constitute the main syndrome, but in most cases these are present with the motor or sensory deficit due to cerebral ischemia, along with headache or Horner's syndrome. In the diagnosis of the first case, there was further difficulty because the cranial nerve palsy was isolated without hemiparesis, and the second case presented a rare association of hemiparesis and palsy of the eleventh cranial nerve alone. Compression or stretching of the nerve by the expanded artery may explain the palsies, but an alternative cause is also possible, namely the interruption of the nutrient vessels supplying the nerve, which in our patients is more likely.