Cervical Artery Dissection

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• Definition & Anatomy: Cervical artery dissection encompasses carotid artery dissection and vertebral artery dissection. It occurs when an injury to one of these vessels allows blood to enter the vessel wall, creating a localized intramural hematoma. Extracranial dissections are significantly more common than intracranial dissections.
• Dual Mechanism of Ischemia: Pathophysiologically, the intramural hematoma can cause direct luminal narrowing or occlusion, resulting in severely reduced blood flow through the artery to the brain. Alternatively, the endothelial damage and intimal flap serve as a nidus for platelet aggregation and thrombus formation; subsequent thromboembolism from this site leads to acute ischemic stroke.
• Aneurysmal Extension: In some cases, the entry of blood into the arterial wall can cause the vessel to become aneurysmal.
• Spontaneous vs. Traumatic Reactivity: Dissections can occur spontaneously (particularly in middle-aged individuals) or follow trauma. While underlying connective tissue disorders (such as vascular Ehlers-Danlos syndrome and fibromuscular dysplasia) and hypertension are major predisposing risk factors, approximately half of all dissections occur with no clearly identified precipitating factor. Traumatic triggers can be remarkably minor, such as coughing, sneezing, neck manipulation, vigorous physical activity, or repetitive neck turning.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Airway and Breathing Stabilization: Assess the patient's airway immediately upon arrival. If the patient is unable to protect their airway or exhibits signs of respiratory compromise, secure a definitive airway with endotracheal intubation using standard rapid sequence intubation (RSI) protocols. Perform a brief, focused neurological examination before administering sedatives and paralytics.
• Hyperacute Stroke Code Activation: If the patient exhibits acute symptoms of brain ischemia and presents within the standard reperfusion window, immediately activate the institutional stroke alert protocol.
• Obtain a baseline National Institutes of Health Stroke Scale (NIHSS) score.
• Check a bedside point-of-care capillary glucose immediately to rapidly exclude hypoglycemia (a major stroke mimic).
• Thrombolytic Therapy: Eligible patients presenting with acute ischemic stroke secondary to cervical artery dissection are candidates for intravenous thrombolysis. Treat them similarly to other stroke patients:
• Alteplase Dosing: Administer 0.9 mg/kg IV total (maximum dose 90 mg). Give 10% of the dose (0.09 mg/kg) as an intravenous bolus over 1 minute, followed by the remaining 90% (0.81 mg/kg) as a continuous intravenous infusion over 1 hour.
• Endovascular Therapy (Thrombectomy): If the patient has a confirmed large vessel occlusion (LVO) in the anterior circulation, discuss the case immediately with a stroke neurointerventionalist at a comprehensive stroke center to determine eligibility for mechanical thrombectomy.
• Antithrombotic Therapy (For Non-Thrombolytic Candidates): In dissection patients who do not qualify for thrombolysis or endovascular therapy, initiate early antithrombotic therapy in the ED to prevent clot propagation.
• Therapeutic Options: The landmark CADISS trial demonstrated no difference in outcomes between antiplatelet therapy (aspirin, dipyridamole, or clopidogrel alone or in combination) and anticoagulation (unfractionated heparin or therapeutic low-molecular-weight heparin followed by warfarin). Some clinicians may also empirically utilize direct oral anticoagulants (DOACs like rivaroxaban, apixaban, or dabigatran). Select the specific agent in conjunction with specialist consultation.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Top "Can't-Miss" Mimics

1. Acute Ischemic Stroke (Atherothrombotic/Cardioembolic): Presents with identical focal neurological deficits but typically occurs in older patients with traditional cardiovascular risk factors. Cervical artery dissection must be suspected in any young patient (<45 years old) presenting with stroke symptoms.
2. Primary Headache Syndromes (Migraine/Cluster Headache): Carotid dissection can present as an acute, severe retro-orbital headache with no prior history of cluster headaches, easily mimicking primary headache disorders.
3. Aneurysmal Subarachnoid Hemorrhage (aSAH): Presents with a sudden, severe thunderclap headache. Subarachnoid hemorrhage can occasionally be the initial presenting feature of a cervical artery dissection.
4. Giant Cell Arteritis (GCA): In patients older than 50, presents with new-onset headache, visual deficits, and jaw claudication.
5. Carbon Monoxide (CO) Toxicity: Presents with headache, dizziness, and nausea in multiple household members.

Prioritized Workup Strategy

• Bedside Point-of-Care Glucose: Performed immediately at triage to rule out hypoglycemia.
• Standard stroke laboratory panels: Complete blood count, comprehensive metabolic panel, and coagulation studies (including PT/PTT/INR).
• Urgent Neurovascular Imaging (CTA or MRA): Contrast-enhanced CT angiography (CTA) or magnetic resonance angiography (MRA) of the head and neck are the diagnostic modalities of choice to visualize the dissection, vascular stenosis, or occlusion.
• The Carotid Ultrasound Rule: Do NOT rely on carotid duplex ultrasound to rule out cervical artery dissection. Its sensitivity is comparatively low (~92%) and it frequently misses critical vascular lesions.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

Standard ECG Visual Checklist

• Arrhythmia Screening: Screen for new-onset atrial fibrillation or other reactive changes associated with acute stroke or intracranial pathology.

Point-of-Care Ultrasound (POCUS) Findings

• Color Duplex US Limitation: Because color duplex ultrasound has low sensitivity and can miss proximal or distal vessel dissections, it should only be used as a rapid, preliminary risk-stratification tool, and any positive or equivocal findings must be confirmed with MRA or CTA.

Neuroimaging Visual Checklist

• Standard Non-Contrast Head CT: Typically normal or non-specific in uncomplicated cervical artery dissection. Its primary ED utility is to rapidly rule out acute intracranial hemorrhage.
• Magnetic Resonance Imaging (MRI) - T1-weighted Axial Sequence:
• Look for the classic "crescent sign" (a hyperintense crescent-shaped mural hematoma in the vessel wall surrounding a narrowed, eccentric flow void).
• CT Angiography (CTA) or MR Angiography (MRA) of the Head & Neck:
• Meticulously trace the internal carotid and vertebral arteries to look for focal narrowing, stenosis, occlusion, dissecting aneurysms, or a double-lumen appearance.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

CADISS Trial Recommendations

• The Cervical Artery Dissection in Stroke Study (CADISS) randomized trial confirmed that there is no significant difference in clinical outcomes (including recurrent stroke or death) when comparing antiplatelet therapy to therapeutic anticoagulation in the acute phase of cervical artery dissection.

Blunt Cerebrovascular Injury (BCVI) Screening Guidelines

• In patients presenting to the ED with blunt head or neck trauma, clinicians must utilize validated screening protocols (such as the Memphis or Denver Criteria) to identify asymptomatic patients who require CTA screening for occult dissection.
• Major Screening Criteria Components:
• Signs/Symptoms: Arterial hemorrhage from the mouth, nose, or neck; cervical bruit in a patient <50 years old; expanding cervical hematoma; or focal neurological deficits (e.g., TIA, stroke, or a partial Horner syndrome).
• Associated Injury Risk Factors: Le Fort II or III midface fractures, mandible fractures, basilar skull fractures (specifically occipital condyle fractures), severe traumatic brain injury (GCS <6), cervical spine fractures, subluxation, or ligamentous injury at any level, near-hanging with anoxic brain injury, or a seat belt abrasion with significant swelling, neck pain, or altered mental status.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

Deadly Cognitive Traps & Trainee Pitfalls

• The "Normal Carotid Ultrasound" Fallacy: Incorrectly assuming a normal color duplex ultrasound rules out a dissection. Carotid ultrasound has a 92% sensitivity and frequently misses dissections.
• Psychiatric Anchoring on Dizziness or Ataxia: Misdiagnosing a young patient with vertebral artery dissection as having a benign peripheral vestibular disorder, anxiety, or conversion disorder, especially when they present with vertigo, vomiting, or ataxia.
• Failing to Recognize Partial Horner Syndrome: Carotid dissection classically presents with a partial Horner syndrome (ptosis and miosis, often sparing anhidrosis). Failing to perform a detailed pupillary and eyelid exam in a young patient presenting with an "atypical migraine" or neck pain is a major pitfall.
• Delaying Thrombolysis for Specialty Consultation: Hesitating to administer IV Alteplase in an eligible patient with an acute ischemic stroke because the stroke was caused by an underlying dissection.

Mandatory Critical Actions

• Document a complete cranial nerve exam and a formal gait assessment on all young patients presenting with "atypical" headaches or dizziness.
• Inquire about minor mechanical trauma (e.g., vigorous exercise, coughing, sneezing, minor falls, or recent chiropractic neck manipulation) in any young patient presenting with new-onset headache or neck pain.
• Incorporate CTA screening for all blunt trauma patients who meet the Denver or Memphis criteria (especially those with cervical spine fractures or seat belt sign).

7. MCQ MASTERCLASS (Written Exam Tips)

High-Yield Exam "Buzzwords" and Associations

• "Young Stroke (<45 years old)": Cervical artery dissection is the single most common cause of ischemic stroke in young patients, accounting for up to 10% to 25% of cases.
• "Chiropractic Manipulation / Vigorous Activity": Classic preceding triggers frequently described in clinical stems.
• "The Crescent Sign": The pathognomonic T1-weighted MRI visual finding of intramural hematoma.
• "Ehlers-Danlos / Fibromuscular Dysplasia": Key genetic and connective tissue disease associations.

Carotid vs. Vertebral Dissection Differentiations

• Internal Carotid Artery Dissection: Unilateral head/neck/face pain (66% unilateral headache, 50% facial/dental pain) + partial Horner syndrome (ptosis, miosis in <50%), followed by cerebral or retinal ischemia (amaurosis fugax). Classically features acute, severe retro-orbital pain mimicking cluster headaches.
• Vertebral Artery Dissection: Severe unilateral posterior neck pain (50%) or occipital headache (66%), which may be bilateral and can precede neurological symptoms by up to 2 weeks. Classically followed by a rapidly progressive deficit of the brainstem and cerebellum (vertigo, vomiting, ataxia, diplopia, tinnitus, unilateral facial weakness).

Differentiating Common Distractors

• Distractor: Choosing anticoagulation over antiplatelet therapy because "anticoagulation is superior."
• Correction: CADISS showed no difference in outcomes. Either strategy is acceptable; select the agent in consultation with neurology.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

Communication Pearls & Initial Script

• "As this young patient presents with acute focal neurological deficits and unilateral neck pain, I am placing them in a monitored resuscitation bay, actively securing their airway, breathing, and circulation, and obtaining an immediate point-of-care capillary glucose to rule out hypoglycemia."
• "I will state clearly to my resuscitation team: 'This is a young patient with stroke-like symptoms; we must activate our hospital's hyperacute stroke protocol immediately'."

Mandatory Physical Exam Phrasing

• "I will perform a detailed neurological examination and calculate a baseline National Institutes of Health Stroke Scale (NIHSS) score."
• "I am explicitly performing a detailed pupillary and eyelid examination, looking for ptosis and miosis to screen for a partial Horner syndrome indicating a carotid artery dissection."
• "I will perform a thorough cranial nerve, cerebellar, and gait assessment, looking for vertigo, nystagmus, dysarthria, and ataxia to screen for vertebral artery dissection."

Smooth Articulation of Management Steps

• "Because this young patient has a focal stroke syndrome in the setting of recent minor neck trauma, I have a high clinical suspicion for cervical artery dissection. To establish a rapid, definitive diagnosis, I will order an emergent contrast-enhanced CT angiography (CTA) of the head and neck."
• "I will state to the examiner that a carotid duplex ultrasound has comparatively low sensitivity and is insufficient to rule out a dissection in the ED; therefore, I will proceed directly with CTA or MRA."
• "If the patient is within the 4.5-hour stroke treatment window and has no contraindications, I will administer IV Alteplase at 0.9 mg/kg, giving 10% as a bolus over 1 minute and the remaining 90% as a continuous infusion over 1 hour. I will concurrently consult a stroke neurointerventionalist to discuss potential endovascular thrombectomy."
• "If the patient is not a candidate for thrombolysis, I will initiate antithrombotic therapy in the ED with either antiplatelet or anticoagulant therapy, as the CADISS trial demonstrated equivalent efficacy between both regimens. I will select the specific agent in close consultation with neurology."
• "For my disposition, if the patient has persistent neurological deficits, I will admit them to the Neurological Intensive Care Unit (ICU). If they are completely asymptomatic with no ongoing deficits, I will consult neurology and safely discharge them home on their antiplatelet or anticoagulant regimen. I will provide strongly worded return precautions regarding their risk of stroke, instructing them to return immediately for any worsening headache, neck pain, or new neurological symptoms."