Cervical Artery Dissection

3 Interesting Facts of Cervical artery dissection

1. Cervical artery dissection is a major cause of ischemic stroke in young adults, often precipitated by trauma, neck hyperextension, or neck rotation
2. Cervical artery (carotid or vertebral) dissections result either from an intimal tear or from direct bleeding within the arterial wall due to ruptured vasa vasorum
   • Internal carotid artery dissections present with a classic triad: ipsilateral headache, partial Horner syndrome, and ischemic symptoms (ie, transient ischemic attack, transient monocular blindness, ischemic stroke)
   • Vertebral artery dissections are associated with posterior neck pain and posterior cerebral or brainstem ischemia
3. Arterial dissection is differentiated from moyamoya arteriopathy based on imaging study findings 
   • On MRI, dissection is seen as a hyperintense, crescent-shaped wall hematoma and an eccentric flow void of the patent lumen
   • On magnetic resonance angiography, axial T1 images through the vessel lumen may show a crescent sign (ie, elliptical bright signal within a vessel wall that surrounds a signal flow void) 
   • On digital subtraction angiography, dissection is seen as a string sign (ie, a smooth tapered luminal narrowing), an intimal flap, or double-barrel lumen
   • Characteristic puff of smoke appearance of moyamoya is not seen in arterial dissections

Tearing between the layers of the wall of an artery in the neck.

Synonyms

• Carotid artery dissection
• Vertebral artery dissection

Epidemiology & Demographics

The most common cervical artery dissection (CAD) is the internal carotid; the vertebral artery is less commonly affected. Cervical artery dissection occurs spontaneously when a tear occurs in the intimal layer of the carotid artery, creating an intramural hematoma.

This tear can be spontaneous or caused by trauma. The intramural hematoma causes the stenosis and eventual thrombus formation leading to stroke, especially in young patients.

Traumatic dissection can either be by blunt or penetrating trauma. Blunt trauma can be significant with motor vehicle accidents, or it can seem minimal such as chiropractic manipulation of the cervical spine.

A motor vehicle accident where there is rapid deceleration with simultaneous neck hyperextension and rotation may lead to an intimal tear of the carotid artery. Idiopathic is the most common cause of spontaneous dissections in which a family history of dissection significantly increases one’s risk.

CAD can happen intracranially (most often) or extracranially (rare but worse prognosis).

Incidence

• •The average annual incidence rate for CAD is reported at 2.6 per 100,000 population; however, the true incidence is likely higher because many cases have self-limited clinical symptoms and remain undiagnosed.
• •Specifically, carotid artery dissections account for 2.5% of all strokes. It is a common cause of stroke in patients younger than 40 yr old. In all young patients, 20% of cerebrovascular accidents (CVAs) are caused by carotid artery dissection. The median age is in the mid-40s, and there seems to be a slightly higher incidence in males versus females.

Prevalence:

Prevalence may reach 15% in the young adult stroke population.

Predominant Gender & Age

Carotid artery dissections are most commonly found in young adults. The mean age for extracranial internal carotid artery dissection is 40 yr. Intracranial dissections are more common in those aged 20 to 30 yr.

Risk Factors

• •Seasonality: 58% more patients experience a cervical artery dissection during autumn and winter for unknown causality.
• •Vascular factors: Hyperhomocysteinemia is strongly associated with CAD, especially if homocysteine levels are >12 micromols/L
• •Chiropractic manipulations are often listed as risk factors, with multiple case reports, although evidence is lacking
• •Major cervical trauma: Hyperextension or rotation of the neck
• •Although evidence is less strong, infection and migraine may also predispose to CAD, as well
• •Arterial wall intrinsic factors, such as arteriopathies, may predispose to arterial dissection after trivial trauma. Angiographic evidence of fibromuscular dysplasia has been noted in 10% to 15% of patients

Genetics

Marfan syndrome, type IV Ehlers-Danlos syndrome, fibromuscular dysplasia, cystic medial necrosis, and the 677TT genotype of the 5,10-methylenetetrahydrofolate reductase gene (MTHFR 677TT) have been reported in association with CAD.

Physical Findings & Clinical Presentation

A young adult with nuchal rigidity, neck pain, and severe occipital headache after minor head or neck trauma is a common presentation. Focal neurologic symptoms follow as a result of ischemia and may include:

• •Ipsilateral facial pain and numbness: Most common focal neurologic complaints
• •Contralateral loss of pain and temperature sensation in the trunk and limbs
• •Loss of taste, hiccups, vertigo, dysphagia, Horner syndrome, unilateral hearing loss, or tinnitus may also occur
• •Aged 18 to 65, complaints of migraines without auras and concern for ischemic stroke
• •In contrast to younger patients, those over 60 rarely report mechanical triggers or pain

Pathophysiology

Arterial wall tears happen either spontaneously or as a result of minor trauma. The tear allows arterial blood under pressure to leak into the wall, creating either a hematoma or a false lumen.

Sometimes the tear is subintimal, whereas other times it is subadventitial. Subintimal tears usually result in stenosis of the arterial lumen, whereas subadventitial dissection tends to cause arterial dilation.

Etiology

Cervical artery dissections may be spontaneous or traumatic. The majority of cases involve minor trauma.

 Diagnosis

• •Ultrasonography: Safe and accurate; however, it has a 31% false negative result in patients with CAD presenting with Horner syndrome
• •CT angiography
• •Conventional angiography
• •MRA is the gold standard for diagnosis

Differential Diagnosis

• •Cervical spine fracture
• •Cluster headache
• •Subarachnoid hemorrhage
• •Hypoglycemia
• •Stroke/transient ischemic attack (TIA)
• •Migraine headache
• •Other neck trauma

Workup

• •Labs not usually required except for determination of renal status for contrast use and coagulation panel. Obtaining blood products may also be necessary in casesof planned surgical intervention (type and cross/match).
• •Screening protocol with modified Memphis criteria, CTA needed for any base skull fracture with involvement of carotid canal or petrous temporal bone, cervical spine fracture, neurological exam findings associated with blunt force trauma that is not explained by any other injury, Horner syndrome, Lefort II or III and neck soft tissue injury such as seatbelt sign, hanging, or hematoma.
• •Imaging studies such as ultrasound, conventional angiography, CT angiogram, or magnetic resonance angiography (MRA) give the ultimate diagnosis. The high false-negative rate in ultrasound limits its utility, and the high complication rate and unavailability of conventional angiography limit its widespread use.

 Treatment

• •Cervical spine immobilization is the first step in the setting of any neck trauma.
• •Initial noncontrast CT of the cervical spine should be ordered to rule out fracture; then consider follow-up with CT angiography or MRA.
• •Anticoagulation therapy should be performed if there is no contraindication or high risk. First one must rule out intracranial hemorrhage and other bleeding source in trauma patients. Anticoagulation with heparin followed by warfarin is generally accepted as sufficient management for prevention of thromboembolic events.
• •In the case of contraindications to anticoagulation therapy, antiplatelet therapy may be used. A recent randomized, prospective, open-label, international, multicenter study with 250 patients showed no difference between anticoagulation and antiplatelet therapy after 12 mo with standard recurrent stroke rate of 2.5%.
• •Do not use anticoagulation or antiplatelet therapy in a pregnant patient without an OB consultation.
• •Other pharmacologic treatment modalities are currently in clinical trials.

Nonpharmacologic Therapy

Operative endovascular management with angioplasty or stent placement is only utilized in select patients. Criteria include:

• •Persistent ischemic symptoms despite adequate anticoagulation
• •Contraindication to anticoagulant therapy
• •An iatrogenic dissection developing during an intravascular procedure
• •Significantly compromised cerebral blood flow

Surgery has limited use in CAD, although surgical consultation is recommended.

Disposition

• •Traumatic dissections: Admit to trauma unit with vascular service input.
• •Spontaneous dissections: Admit to stroke service and potentially refer to vascular if endovascular intervention is recommended.

Referral

Vascular surgery

Complications

• •Occlusion leading to ischemic stroke
• •Thrombosis and embolization leading to TIAs
• •Subarachnoid hemorrhage if the dissection is intracranial
• •Pseudoaneurysm formation

 Pearls & Considerations

In young patients with stroke-like symptoms or acute onset neck pain or headache, consider cervical artery dissection.

Blunt cerebrovascular injuries (BCVIs) are present in 3.3% of multitrauma patients.

BCVIs are significantly associated with the Memphis risk factors. Of the multitrauma patients affected by BCVIs, 37.5% do not show clinical-radiological risk factors.

There is current active debate regarding universal screening. If it is in your differential, scanning with CTA may be reasonable even without hard signs that would otherwise require CTA.

Suggested Readings

• Blum C.A., et al.: Cervical artery dissection: a review of the epidemiology, pathophysiology, treatment, and outcome. Arch Neurosci 2015; 2 (4): pp. e26670.
• Bonatti M., et al.: Blunt cerebrovascular injury: diagnosis at whole-body MDCT for multi-trauma. Insights Imaging 2013; 4: pp. 347-355.
• De Giuli V., et al.: Association between migraine and cervical artery dissection: the Italian Project on Stroke in Young Adults. JAMA Neurol 2017; 74 (5): pp. 512-518.
• Debette S., et al.: Cervical-artery dissections: predisposing factors, diagnosis and outcome. Lancet Neurol 2009; 8 (7): pp. 668-678.
• Life in the Fast Lane Medical Blog: https://litfl.com/cervical-artery-dissection/. Markus HS et al: Antiplatelet therapy vs. anticoagulation therapy in cervical artery dissection: the Cervical Artery Dissection in Stroke Study (CADISS) randomized clinical trial final results, JAMA Neurol 76(6):657-664, 2019. https://doi.org/10.1001/jamaneurol.2019.0072.
• Traenka C., et al.: Cervical artery dissection patients ≥60 years: often painless, few mechanical triggers. Neurology 2017; 88: pp. 1313-1320.