Introduction

Headache and neck pain are extremely common chief complaints in the emergency department. One study found that “symptoms involving head and neck” was the sixth-most common ED diagnosis, seen in 2.2% of ED visits.¹ The estimated 1-year incidence of neck pain alone can be more than 20%.² The majority of patients with headache and neck pain do not have a life-threatening problem. The challenge for emergency physician is to recognize signs of cervical artery dissection in patients presenting with head and neck pain. Early identification and treatment of dissection reduces the risk of stroke and death.

While the overall incidence of cervical artery dissection is very low, it is a common etiology of stroke in adults younger than 50, causing up to 10% of the cases.³ Incidence has increased in the past decade, likely due to improved imaging modalities. The incidence of spontaneous cervical arterial dissection is 3-5 per 100,000.⁴ The incidence of traumatic cervical artery dissection is 1 per 1000.⁴ Cervical arterial dissections most commonly occur in the carotid arteries, followed by the vertebral arteries.

Pathophysiology

Dissection is caused by an intimal tear leading to bleeding into the vascular wall, which can lead to vessel occlusion, thrombus with subsequent distal emboli, aneurysm formation, and subarachnoid hemorrhage. Arteries are most prone to dissection when they are stretched over bony prominences. Carotid artery dissection most commonly occurs 2 cm above the bifurcation of the common carotid artery, where the extra-cranial portion of the internal carotid artery travels over C2-3. Vertebral artery dissection most commonly occurs at C1-2, due to compression of the vessel against the C2 cervical foramina during head rotation, and at C5-6, where the artery enters the transverse foramina.⁴ Compression of the vessel can cause blood to pool and clot in the vessel, then subsequently embolize to distal vessels, resulting in ischemic stroke.

Clinical presentation

Early presentation of cervical artery dissection can be very subtle and overlaps with more common causes of headache and neck pain like tension headache or musculoskeletal neck pain. Up to 80% of cervical artery dissections are preceded by trauma to the head or neck.³ Dissection has been associated with chiropractic manipulation, weight lifting, roller coasters, and wrestling.^4,5

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

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.

Most, but not all, patients with vertebral artery dissection have a headache.⁷ Headache is severe, unilateral, and often posterior-occipital. Whereas patients with carotid artery dissection may present with a wide variety of types of headaches, the quality of the headache in vertebral artery dissection is much more consistently unilateral and severe.⁷ Almost half of patients have neck pain of gradual onset. Less commonly, patients will present with isolated neck pain and no headache. On exam, patients may have neck tenderness with palpation. Do not be falsely reassured by reproducible neck pain when it comes to evaluation of vertebral artery dissection.

When compared to carotid artery dissection, vertebral artery dissection is more likely to affect younger patients. It is more common in women and in patients with chronic migraines.

Diagnostic studies

Once you suspect cervical artery dissection, choosing the appropriate imaging modality is key. The usual approach to a new headache in the emergency department is a non-contrast head CT and possible lumbar puncture. Unfortunately this may miss uncomplicated cervical artery dissection, leading to delays in the diagnosis and subsequent stroke or death. Historically, cerebral angiography has been the “gold standard” for diagnosis of dissection. Angiographic findings suggestive of dissection include intimal flaps, pseudo- aneurysm, and luminal stenosis or occlusion.³ However, cerebral angiography is less commonly used today due to the invasive nature and the risks of the procedure. Conventional angiography has been replaced in the ED by the faster and more readily available magnetic resonance angiography (MRA) and computed tomography angiography (CTA). In some populations, the introduction of MR and CT has increased the rate of diagnosis of cervical artery dissection up to 10-fold.⁸ Ultrasound has been studied in cervical artery dissection, but it is less sensitive than CTA or MRA.

The largest series comparing MRA to traditional angiography found a sensitivity of 83% and a specificity of 99% for carotid artery dissection and a sensitivity of 20% and a specificity of 100% for vertebral artery dissection.⁹ Accuracy of CTA has improved over the past decade with the use of multi-detector CT scanners, with a sensitivity of 90% and a specificity of 100%.¹⁰

The general consensus among experts is that CTA is the better screening test because it is faster, cheaper, and shows excellent visualization of large vessels, including the carotids and vertebrals. If CTA shows dissection, MRA is an appropriate follow-up test because it allows for better visualization of small vessels and will also show cerebral ischemia if present. A reasonable initial approach to a patient with a suspected cervical artery dissection would be to obtain a non-contrast head CT, and if negative, proceed with a CTA head and neck. If dissection is identified, obtain MR brain and MRA head and neck for further evaluation.

Emergency department management

The management of patients diagnosed with cervical artery dissection begins with evaluation of candidacy for fibrinolytic therapy with tissue plasminogen activator (tPA). This should be done in consultation with a neurologist. Dissection patients were included in the National Institute of Neurological Disorders and Stroke IV tPA trial (NINDS).¹¹ No adverse bleeding events were seen. There was slightly less neurologic improvement seen in the dissection group compared with the non-dissection group (but still greater than the control group). Most patients with dissection present much later than the 3-hour symptom window for tPA, and the dissection must be limited to extra-cranial vessels in order for tPA to be considered. Emerging research suggests that endovascular stenting may also improve neurologic outcomes in dissection patients in the acute phase of stroke.¹² Admit all patients with cervical artery dissection to a telemetry-monitored hospital bed, as even patients who are relatively asymptomatic from their dissection may progress to ischemic stroke with devastating neurologic deficits.

The long-term treatment of cervical artery dissections is anti-platelet therapy with aspirin 325 mg daily or anticoagulation with warfarin with a goal INR 2-3 for 3-6 months. Both have been shown to reduce the progression to ischemic stroke. No study has ever shown a significant advantage of anticoagulation over anti-platelet therapy.¹³ In one study, treatment of traumatic dissection with anti-platelet or anticoagulant therapy reduced the incidence of stroke from 64% to 6.8% for carotid dissection and from 54% to 2.6% for vertebral dissection.¹⁴ If the patient is not a candidate for tPA, then a heparin drip should be started in the ED. Once the patient is admitted, the neurologist can then determine whether the patient will ultimately be on aspirin or warfarin. Blood pressure goals in the acute setting have not been clearly established, but pilot studies recommend permissive hypertension of the systolic blood pressure up to 200 mm Hg.⁴

Conclusion

Headache and neck pain are common chief complaints in the emergency department. While they are usually of benign etiology, they might represent early symptoms of a cervical arterial dissection. Dissection needs to be considered in any young patient who presents with neurologic symptoms or signs. Important clinical clues that suggest dissection include any focal neurologic deficit in the setting of headache, facial pain, or neck pain. A partial Horner syndrome should heighten your suspicion. In every case, emergency physicians should question patients about any preceding trauma, and be sure to tell them it doesn’t matter how trivial that trauma might seem. Typical screening tests like non-contrast CT and lumbar puncture may miss an uncomplicated dissection. When dissection is suspected, CTA neck is the next appropriate test. Making the diagnosis is critical, as progression to stroke can be reduced by appropriate therapy. Long term anti-platelet or anticoagulation therapy is recommended.

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