Carotid artery dissection accounts for 20–30% of all ischaemic strokes in patients younger than 50 years of age4
and is the underlying mechanism in 2.5% of all strokes.6
There is a high risk of recurrent stroke within the first 4 weeks; however, after this recurrence is rare (about 1% per year).
Carotid artery dissection can occur intracranially and extracranially, with the latter being more frequent. Internal carotid artery dissection can be a result of mechanical forces such as trauma or stretching7 8
as well as underlying connective tissue disorders such as Ehlers–Danlos syndrome IV.4 9
Other risk factors include hypertension, hyperlipidaemia, diabetes mellitus, smoking and the combined contraceptive pill.4
Arterial dissection begins as a tear in the tunica intima or between the tunica media and tunica adventitia and then under arterial pressure; blood dissects along the artery, resulting in an intramural haematoma (). This process can result in stenosis or thromboemboli and lead to ischaemic stroke; also, aneurismal outpouchings may compress the lower cranial nerves.5 9
Illustration of arterial dissection.
A high degree of suspicion should be taken in to account even after low-impact trauma. Ten investigations are considered mandatory in the presence of (1) a potential arterial origin haemorrhage from the nose, ears, mouth or a wound; (2) an expanding cervical haematoma; (3) cervical bruit in a patient >50 years of age; (4) evidence of acute infarct at brain imaging; (5) unexplained central or lateralising neurological deficit or TIA; or (6) Horner's syndrome, neck or head pain. A number of centres screen asymptomatic patients with blunt trauma for dissection.
Colour duplex ultrasound, CT, CT angiogram and magnetic resonance angiography are non-invasive screening methods. Catheter angiography is the gold standard but is rarely required for diagnosis.10
Prompt hospital referral is essential while assessing disability in young-age patients, and thrombolysis with rT-PA (Alteplase) should be considered in this group of patients, regardless of dissection, as would be the case in treating any other ischemic stroke. Despite a common fear of thrombolysis in this group, recent studies indicate that thrombolysis should not be excluded in patients who might have carotid artery dissection.11
Rarely, endovascular therapy may be indicated for the treatment of ruptured aneurysms or to prevent recurrent ischaemia.5
Endovascular treatment of traumatic internal carotid artery injury continues to evolve.12 13
Thromboarterectomy, direct suture of intimal tears and extracranial-intracranial bypass should be considered in exceptional cases.10
Patients with dissection-related cervical artery occlusion have a significantly increased risk of suffering a disabling stroke.14
This case highlights the importance of recognising the possible causes of TIA/stroke in the young- and middle-age groups in Emergency departments.
- When a young- or middle-aged person, without vascular risk factors, presents with symptoms of TIA/stroke, dissection must be ruled out.
- There are various possible presentations of carotid artery dissection.
- High-risk TIAs should be admitted, where available, to acute stroke units.
- Prompt hospital referral is essential for looking at disability in young age and thrombolysis should be considered.