emDOCs Podcast – Episode 97: Spontaneous Cervical Artery Dissection

Definition/pathophysiology:

• sCAD refers to a tear or separation of arterial wall layers involving either the carotid or vertebral arteries. Creates a false lumen where blood may enter the vessel wall between the intima and the media or between the media and the adventitia.
• An intramural hematoma and subintimal dissection can cause luminal stenosis and occlusion.
• Thromboembolism can lead to stroke (and this is a more common cause of stroke in the setting of sCAD than hypoperfusion).
• An aneurysm or hematoma can occur and lead to compression of surrounding nerves and vasculature.

Epidemiology

• Common cause of strokes in young people; sCAD accounts for 15-24% of strokes in patients < 45 years.
• Rare cause of stroke overall – incidence is 1.72 per 100,000 individuals for internal carotid artery dissection, 0.97 per 100,000 individuals for vertebral artery dissection, and 2.6-3 per 100,000 for combined cases.
• Risk factors include connective tissue disorders (e.g., fibromuscular dysplasia, Ehlers-Danlos syndrome) and vascular disease.
• While most cases occur with a mechanical trigger, many patients will not recall an inciting event and are unaware of any major risk factors that lead to the vascular injury and dissection.

Presentation

• Many will have no symptoms or local symptoms like neck pain or headache on the side of the dissection (usually anterior carotid dissection and posterior for vertebral dissection).
• Symptoms are often sudden with headache and face or neck pain.
• May find partial Horner syndrome – ptosis and miosis but no anhidrosis – in patients with carotid dissection.
• Cranial neuropathies can happen due to compression of the nerve fibers.
  • Non-stroke cranial neuropathies should really only involve CN XII or XI – the ones in the neck that travel near the carotid.
• Monocular blindness, unilateral extremity weakness, and sensory changes can occur with carotid dissection.
• Vertigo, dysmetria, ataxia, diplopia, nausea, vomiting, or vision changes with vertebral dissection.
• Pulsatile tinnitus is a red flag.
• Vertebral dissection can lead to ischemia or infarction of the cervical spinal cord, leading to unilateral extremity weakness.
• sCAD can extend intracranially and cause SAH (altered mental status, focal neurologic deficits, and severe headache).

Evaluation

• CTA of the head and neck is first line modality; fast, reliable, widely available, high sensitivity.
• If a patient has contraindications to CTA such as an iodinated contrast allergy, MRI with MRA is an option.
• Ultrasound can miss this diagnosis (especially of the vertebral arteries, which are not easily visualized on US).

Management

• Consult neurology. May need neurosurgery (SAH or LVO present).
• Patients with sCAD but no associated stroke symptoms should receive antithrombotic or antiplatelet therapy to reduce their risk of thromboembolic stroke secondary to the dissection.
  • They will need to continue this for 3-6 months and follow up with neurosurgery or vascular surgery, depending on the institution.
• Data on antiplatelet versus anticoagulation suggest similar outcomes. Stroke rates are similarly low for patients who receive anticoagulation compared with antiplatelets.
• Consulting specialist will select which agent they prefer.
• Contraindication to medical therapy: endovascular interventions may be necessary (angioplasty or embolization of the dissected vessel).
• If SAH present, no antiplatelet or anticoagulant agents. Need immediate neurosurgery consultation and may require therapy to lower their intracranial pressure, antihypertensives, calcium channel blockers.
• If ischemic stroke present, thrombolytics may be administered if they present within the 3-4.5 hour window, they have no contraindications, and their NIH Stroke Scale score is high enough to justify it.
  • Contraindications to thrombolytics: intracranial extension, ICH, or involvement of the aorta.
• BP management: No clear guidelines.
  • If the patient is having a stroke from their sCAD, follow typical BP targets for whichever type of stroke it is.
  • If it’s ischemic, maintain BP < 185/110 mm Hg prior to administration of thrombolytics followed by < 180/105 mm Hg.
  • If no thrombolytics, goal SBP < 220 mm Hg systolic.
  • If SAH or ICH, goal SBP < 140-160 mm Hg.
  • Consider use of nicardipine or clevidipine.

Summary:

• sCAD is a tear or separation of arterial wall layers involving either the carotid or vertebral arteries.
• Patients most commonly present with unilateral headache or neck pain, but partial Horner syndrome or cranial neuropathies may be present.
• Stroke may occur due to cerebral hypoperfusion or a thromboembolism.
• Consider sCAD in younger patients with stroke-like symptoms.
• First line imaging modality is CTA head and neck.
• For patients without a stroke, treatment usually involves antiplatelet or anticoagulant therapy.
• Stroke patients – whether hemorrhagic or ischemic – should be treated as per our usual stroke management algorithms. Get your consultants on board early.

References:

Long B, Pelletier J, Koyfman A, Bridwell RE. High risk and low prevalence diseases: Spontaneous cervical artery dissection. Am J Emerg Med. 2024 Feb;76:55-62.

Click to access The-EM-Educator-Series-Cervical-Vessel-Dissection.pdf

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