Cervical artery dissection

Reviewed and revised 22 December 2015; adapted from a summary by James Hayes

OVERVIEW

  • Cervical artery dissections is the collective term for dissections of the carotid or vertebral arteries
  • They are important causes of stroke in younger people and are often difficult diagnoses to make
  • Dissection can affect any artery of the neck
    • internal carotid artery is most commonly affected
    • vertebral artery dissections are uncommon
  • Carotid and vertebral artery dissections can occur intracranially and extracranially; the former is rarer and more serious
  • They may be spontaneous or traumatic in etiology
  • Therapies include: antiplatelet therapy, anticoagulation with heparin, thrombolysis (in certain cases) and endovascular interventions

EPIDEMIOLOGY

  • Cervical artery dissections can occur in all age groups
  • important cause of stroke in younger people (< 40 years)
  • Carotid artery dissections are most common in young adults. While the mean age for extracranial internal carotid artery dissection is 40 years, intracranial dissections are more common in those aged 20-30 years.
  • ~ 20% of strokes in the young are caused by carotid artery or vertebral artery dissections in the neck, compared to only 2.5% in older patients

CAUSE

Traumatic cervical artery dissections

  • can be minor or major trauma, blunt or penetrating
  • Dissection may even follow relatively minor indirect trauma, such as neck manipulation by a chiropractor

Spontaneous cervical artery dissections

  • often idiopathic, with an increased incidence if there is a positive family history
  • may be related to underlying vascular pathologies such as:
    • Hypertension
    • Marfan’s syndrome
    • Fibrocystic dysplasia
    • Arteritis/ connective tissue diseases

PATHOPHYSIOLOGY

Usual mechanism:

  • initial intimal tear arises spontaneously or due to traumatic insult
  • The tear allows blood under arterial pressure to enter the wall of the artery and form an intramural hematoma, or “false lumen”
  • The intramural hematoma is located within the layers of the tunica media, but it may be eccentric, either toward the intima or toward the adventitia
    • subintimal dissection tends to result in stenosis of the arterial lumen
    • subadventitial dissection may cause dilatation of the artery

Complications

  • Vessel occlusion, may cause stroke
  • Thrombus formation with embolism of thrombus fragments, may cause stroke (or TIAs in the setting of transient haemodynamic instability)
  • Vessel rupture, results in subarachnoid hemorrhage if occurs intracranially
  • Pseudoaneurysm formation

ASSESSMENT

Diagnosis can be difficult

  • always consider cervical artery dissection if stroke or TIA occurs in in a young person
  • may present initially as vague headaches, facial pain or neck pain

History

  • Pain
    • unexplained, facial or neck pain or headache
    • may precede a  TIA (including amaurosis fugax) or completed stroke, in the cervical artery distribution, by hours or even days
    • usually ipsilateral to the side of the dissection
    • precise location of pain is neither sensitive nor specific for the artery of dissection, however:
      • carotid dissection tends to present with some or all of the following:
        • frontal headache
        • anterior neck pain
        • eye, ear, or face pain
      • vertebral artery dissectiontends to present with some or all of the following:
        • occipital headache
        • posterior neck pain
  • Neurological deficits, such as hemiparesis, may be present
  • History of trauma suggests traumatic dissection, but may be trivial or unrecognised
  • Past history of vascular disorders
  • Family history

Examination

  • Neurological deficits:
    • Hemiplegia/ hemisensory loss
    • Unilateral cranial nerve deficits may be associated with brainstem ischemia
  • Vascular bruits (absence does not exclude dissection, e.g. present in only about 1/3 of carotid dissections)
  • Ipsilateral neck tenderness (recurrence of neck pain and tenderness may indicate an extension to the dissection)
  • Ipsilateral Horner’s syndrome (due to expansion of the internal carotid artery with compression of sympathetic nerve fibers)
  • Evidence of vascular traumatic injury
    • Expanding neck hematoma
    • Hemiplegia in the alert patient
    • development of a depressed level of consciousness in the patient who was initially lucid, without obvious head injury, or who had a normal head CT (suggests development of cerebral ischemia secondary to vascular injury)

INVESTIGATIONS

Bedside

  • BSL (rule out hypoglycemia in patients with neurological deficits)
  • ECG (AF suggests an alternative cardiac source of emboli)

Laboratory

  • FBC
  • ESR and CRP
  • UEC
  • Coagulation profile

Imaging

  • Carotid Doppler Ultrasound
    • useful initial screen, especially if MRA or CTA is not available
    • Limitations:
      • does not image the distal internal carotid artery and intracranial arteries
      • does not image the vertebral vessels
      • less sensitive compared to CT angiogram or MRA
  • CT Brain/ CT angiogram
    • part of the routine initial investigation for any patient who presents with stroke
    • should be done prior to any patient who is to be anticoagulated, to rule out associated intracranial haemorrhage
  • MRI / MRA
    • useful alternative to CTA if significant contrast allergy or renal impairment.
  • Digital Subtraction Angiography (DSA)
    • gold standard of imaging modalities
    • provides clear images and better assessment of blood flow than CTA or MRA imaging
    • can provide information on collateral blood flow and guide further management and stratify risk
    • Patients with an intact circle of Willis should tolerate an acute occlusion much better than those who do not
    • With the ready availability of CTA, DSA is rarely required, unless the CTA is equivocal, and strong clinical suspicion remains

MANAGEMENT

Treatment is not standardised, and depends on numerous factors:

  • Cause: traumatic or spontaneous?
  • Anatomic location of the lesion: carotid versus vertebral? Intracranial versus extracranial?
  • Complicating factors: associated hemorrhage?

Options include:

  • antiplatelet therapy
  • anticoagulation with heparin
  • thrombolysis (in certain cases)
  • endovascular interventions

Antiplatelet therapy

  • Some experts prefer antiplatelet agents in preference to heparin
  • Heparin may be preferred for cases where there are recurrence of symptoms
  • Antiplatelet agents are a safer option in traumatic cases
  • Specifically preferred with:
    • intracranial dissections (risk of hemorrhage)
    • large infarcts (NIHSS score > 15) (risk of hemorrhagic conversion)

Anticoagulation with heparin and warfarin

  • Goal is to prevent further progression of neurological deficits
  • Only considered once intracerebral hemorrhage is ruled out by CTB
  • Heparin is not contra-indicated in patients with extracranial dissections
  • Contra-indications:
    • intracranial dissections (increased risk of hemorrhage, causing SAH)
    • large infarcts (NIHSS score > 15 or severe neurological deficits) (risk of hemorrhagic conversion)

Thrombolysis

  • tPA may be considered in some patients with stroke due to spontaneous extracranial dissection
  • Less improvement is expected in cervical artery dissection stroke patients than for non-dissection acute stroke patients
  • Contra-indications:
    • intracranial dissections (increased risk of hemorrhage, causing SAH)
    • aortic involvement (Risk of catastrophic haemorrhage from aortic rupture)

Endovascular intervention

  • Endovascular therapies include stenting
  • usually used for extracranial carotid or vertebral artery dissection when medical management fails or is contraindicated
  • improved outcomes are associated with reconstitution of flow within 6 hours, which expands the therapeutic window beyond that for lytic therapy
  • Previous medical therapy with thrombolysis, antiplatelet therapy, or anticoagulation does not exclude subsequent endovascular therapy; however, the therapeutic time window may have passed.

Trauma:

  • high risk patients should be invstigated with aggressive screening protocols to identify cervical dissections before the development of stroke symptoms

Disposition

  • traumatic dissections: usually admitted under the Trauma Unit with Vascular Unit input
  • spontaneous dissections: usually admitted under the Stroke Unit and referred to the Vascular Unit if potentially suitable for endovascular intervention

PROGNOSIS

  • Outcomes vary from transient neurologic deficit to permanent deficit and death
  • Prognosis of carotid artery dissection depends on the severity of the initial ischemic episode, the degree of collateral circulation, the site of the dissection and the presence of complications
  • Risk of stroke
    • greatest in the first 24 hours after cervical artery dissection and decreases over the next 7 days
    • relatively low after 2 weeks
  • Extracranial dissection has more favourable prognosis than intrcranial dissection
  • Spontaneous extracranial dissection, with recanalization typically occurring within 7-30 days
  • Intracranial internal carotid artery dissection has high mortality (75%)

References and links

Journal articles

  • Blum CA, Yaghi S. Cervical Artery Dissection: A Review of the Epidemiology, Pathophysiology, Treatment, and Outcome. Archives of neuroscience. 2(4):. 2015. [pubmed] [free full text]
  • Thanvi B, Munshi SK, Dawson SL, Robinson TG. Carotid and vertebral artery dissection syndromes. Postgraduate medical journal. 81(956):383-8. 2005. [pubmed] [free full text]

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health, a Clinical Adjunct Associate Professor at Monash University, and the Chair of the Australian and New Zealand Intensive Care Society (ANZICS) Education Committee. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

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