carotid artery dissection

Etiology

• spontaneous:
  • connective tissues disease
  • Ehlers-Danlos syndrome type-4
  • fibromuscular dysplasia
  • pseudoxanthoma elasticum
  • cystic medial necrosis
  • Marfan syndrome
  • polycystic kidney disease (autosomal dominant)
  • osteogenesis imperfecta type-1
  • syphilitic arteritis
  • oral contraceptives
  • smoking
  • drug abuse
• traumatic:
  • mostly from high-speed motor vehicle accidents (Whiplash)
  • chiropractic cervical spinal manipulation or strain
  • blunt trauma (high impact)
  • pentrating trauma

Epidemiology

• accounts for 25% of strokes in young & middle-age patients
• occurs most frequently in the fifth decade of life
• annual incidence of spontaneous dissection 0.003%
• incidence of traumatic dissection < 1-3%

Pathology

• extracranial dissection more common than intracranial dissection
• dissection begins as a tear in the tunica intima or between the tunica media & tunica adventitia
• it is suggested that pathology may originate in the vasa vasorum
• arterial pressure dissects the artery to create an intramural hematoma, which may result in carotid stenosis or formation of an aneurysm
• thromboemboli can result in ischemic stroke
• aneurysm may put pressure lower cranial nerves
• transient retinal ischemia or retinal infarction may occur
• cerebral hemispheric dysfunction

Clinical manifestations

• non-specific complaints of headache, neck pain or facial pain
  • thunderclap headache in 20%
  • pain is generally in the ipsilateral neck, face, orbit, or frontotemporal cranium
• may present as Horner's syndrome; ipsilateral Horner's syndrome may occur (acute onset)
• combination of abrupt onset cervical pain with Horner's syndrome
• patients may or may not have defined episode of head trauma
• generally a delay of hours from a traumatic event to development of stroke caused by a dissected carotid artery
• retromandibular pain is often the presenting symptom
• contralateral hemiparesis & hemisensory deficit may occur
• other variable manifestations
  • amaurosis fugax
  • pulsatile tinnitus
  • diplopia
  • Broca's aphasia
• symptoms may fluctuate in severity
• patients >= 60 years of age less likely to present with cervical pain (RR=0.47), headache (RR=0.58), or history of mechanical triggers (RR=0.53)

Laboratory

• in general not helpful, unless surgery is contemplated
• complete blood count
• coagulation profile
  • prothrombin
  • activated partial thromboplastin time

Diagnostic procedures

• electrocardiogram may be useful for identifying atrial fibrillation, a source of emboli
• echocardiogram may identify atrial thrombus or other risk factors for embolic stroke
• electroencephalogram may identify primary CNS pathology contributing to patient status
• carotid ultrasound (doppler) screening may identify carotid artery dissection

Radiology

• magnetic resonance angiography
• CT angiography
• pathognomonic 'intimal flap' may be noted with angiography
• computed tomography or MRI of brain may identify CNS pathology contributing to patient status

Complications

• embolic stroke
  • thrombus formation at the site of dissection
  • arterial thromboembolism
• stroke 2% with aspirin therapy
  • risk of recurrent stroke is 2.5% at 1 year
• mortality with spontaneous dissection is < 5%

Management

• aspirin 81-325 mg PO QD for platelet inhibition better than heparin followed by warfarin;
• pediatrics: aspirin 10-15 mg/kg/dose PO every 4-6 hours; not to exceed 60-80 mg/kg/day
• patients with angiographically documented thrombus may benefit from anticoagulation
• aspirin is not non-inferior to vitamin K antagonist (warfarin)
• no evidence that antiplatelet agents or anticoagulants of benefit in reducing risk of recurrent stroke
• consider consultation with neurology, neurosurgery, interventional radiology
• carotid artery stenting is risky & of unproven benefit

More general terms

• carotid artery disease
• arterial dissection

Additional terms

• internal carotid artery (ICA)
• vertebral artery dissection