SUMMARY Though the syndrome of carotid artery dissection is well known, "spontaneous" vertebral artery dissection is rarely recognized. We now report clinical and radiologic findings in five patients with presumed vertebral dissection, one pathologically confirmed.Mean age was 35.2 years (range 27-41). Two were men; three women. None had hypertension, vascular disease, or trauma. Headache and neck or occipital pain was prominent in all, often preceding other symptoms. Four of five patients had unilateral partial alteral medullary syndromes, in one accompanied by medial medullary signs. One patient had a cerebellar infarct. Angiography in four patients showed severe irregular stenosis of the distal extracranial vertebral artery (three bilaterally and subsequently has been widely reported.3 " 5 Migraine 6 ' 7 and fibromuscular dysplasia 8 have been associated with arterial dissection. Intramural clot separates the media often compromising the lumen; clot can dissect into the lumen through the torn intima. Because of intimal and endothelial disruption platelet nidi can form in the lumen and reduced flow potentiates the development of intraluminal clot. Distal ischemia is caused by emoblization of luminal clot or reduced distal flow. Dissections and intimal tears are usually traumatic and are termed "spontaneous" when no definite trauma is recalled by the patient. Though "spontaneous" dissection of the vertebral artery has been reported, 19 " 14 the clinical and radiologic features are less well known than the findings in carotid dissection. We now report clinical and radiologic findings in 4 patients with presumed vertebral artery dissection and radiographic and pathologic findings in 1 patient with surgically proven vertebral dissection. The clinical and radiologic signs of spontaneous vertebral dissection closely resemble those described in vertebral artery trauma and chiropractic manipulation. She recalled no unusual recent neck motion or trauma. Two hours after awakening, she suddenly noted tingling at the corner of her left mouth and tongue, dizziness, vomiting, and a sensation that her body was being pulled to the left. Later her right hand felt cold. On examination, blood pressure and general examination were normal. Neurological abnormalities included: coarse horizontal nystagmus to the left, left facial hypalgesia, diminished left corneal response, and left limb dysmetria. She veered to the left when she walked. CT was normal. Bilateral vertebral angiography showed moderately severe narrowing and irregular stenosis of the third segment of the right vertebral artery and severe stenosis of a short segment of the third portion of the left vertebral artery ( fig. la, b). Warfarin anticoagulation was begun. Neurologic examination returned to normal and she had no symptoms. A left vertebral angiogram 5 months after onset was normal with no residual stenosis ( fig. lc). Warfarin was stopped. Two years after the original episode, the patient had no neurologic signs or symptoms.
Patient 2fJ.R., a 39 year old man ha...