Blunt and penetrating neck trauma may also cause cervical artery dissection. However, the inciting incident may be so benign that the patient may not even remember it. Dissection has been reported following activities as innocuous as shaving, vomiting, yoga, massage, nose blowing, and swimming.3 Symptoms usually start immediately after the traumatic event, although some patients may not experience any symptoms for a week. The average time from traumatic event to onset of symptoms is 2-3 days.6 What further complicates the diagnosis is that the typical ED evaluation of a new headache – non-contrast computed tomography (CT) scan of the head and possible lumbar puncture – will miss most cases of dissection. Ischemic stroke occurs in up to 86% of all dissections and is the presenting symptom in 72%.6 The mean age for carotid artery dissection is 47, and that for vertebral artery dissection is 40.7.7 About 5% of patients have underlying vascular abnormalities such as fibromuscular dysplasia, Marfan’s syndrome, or osteogenesis imperfecta.4
Explore This IssueACEP News: Vol 32 – No 02 – February 2013
Carotid artery dissection
While affecting only 8% of patients, the triad of headache, ipsilateral oculosympathetic paresis, and contralateral stroke symptoms is very concerning for carotid artery dissection.2 Oculosympathetic paresis (also referred to as a partial Horner syndrome) is defined as ptosis and miosis without anhidrosis. This phenomenon is caused by ischemia or compression of sympathetic fibers that run from the internal carotid artery plexus. Facial sweating is preserved because the external carotid plexus is not affected. Almost a third of patients have a partial Horner syndrome.5
Headache is present in up to 75% of patients.7 The headache of carotid artery dissection may be gradual onset or thunderclap, and it may resemble prior migraines. The quality of the headache is neither sensitive nor specific for carotid artery dissection. Up to 50% of patients have a history of prior migraines or other similar headache.2 Some patients complain of facial or scalp pain rather than headache. Neck pain is typically located over the anterolateral aspect of the neck, up to the jaw and even the ear. Dysgeusia (abnormal taste) is only seen in up to 7% of patients, but when present, is very specific for dissection.4 Neither bruits nor pulsatile tinnitus is sensitive or specific for dissection. Signs of stroke develop in most patients. The most common distribution for cerebral ischemia is the middle cerebral and anterior cerebral arteries. Cranial nerve palsies are present in about 10%.4
Vertebral artery dissection
Patients with vertebral artery dissection present with unilateral headache with signs and symptoms consistent with lateral medulla ischemia. Lateral medulla ischemia, also known as Wallenberg syndrome, is characterized by dysmetria, ataxia, ipsilateral hemiplegia, and contralateral loss of pain and temperature sensation.3 Patients may complain of double vision, dizziness, and vomiting, often referred to as “cerebellar signs.” It is important to distinguish between “blurry vision” and “double vision.” Many patients in the emergency department will report blurry vision on review of symptoms, which is likely just presbyopia. Specifically ask about double vision or visual field cuts. The presence of either of these should raise the concern for neurologic deficits.