vertebral artery dissection

introduction

vertebral artery dissection is an uncommon event occurring in ~1 in 100,000 population per annum
along with internal carotid artery dissection, it accounts for ~20% of ischaemic stroke (CVA) in young adults
most common age is the early forties
16% are bilateral
8% have aneurysmal dilatation
rarely occurs as an acute catastrophic fatal injury from a direct blow to the neck such as by a cricket ball

headache with occipital neck pain (~65%) - this is usually gradual onset but of sudden onset in 20%
other features are much more variable:
- tinnitus
- audible bruit
- transient ischaemic attack (TIA) (~20%)
- ischaemic stroke (CVA) (~80%)
- subarachnoid haemorrhage (SAH) (~1%)

mechanical trauma in prior month - often minor (~40% cases)
- sports, yoga
- chiropractic neck manipulation
- amusement park rides
Valsalva events:
- childbirth
- coughing
- sneezing
- sexual intercourse
predisposing factors:
- fibromuscular dysplasia (FMD) is present in 15-20%
- other connective tissue (CT) disorders although very few appear to have a well defined genetic cause

if sudden onset headache, Mx initially as per suspected subarachnoid haemorrhage (SAH)
if clinical features suggest dissection then consider:
- urgent MRA or CT angiography (both have similar sensitivity and specificity for dissection)
- signs include:
  - long tapered arterial stenosis
  - a tapered occlusion
  - a dissecting aneurysm (pseudoaneurysm)
  - an intimal flap
  - a double lumen
  - an intramural hematoma

if acute ischaemic stroke (CVA) without subarachnoid haemorrhage (SAH) within 3-4hrs onset is present, consider thrombolysis - although this is quite controversial, may increase extension of the dissection, and risks may exceed the benefits
other patients with [stroke]] and without subarachnoid haemorrhage (SAH):
- if large ischaemic area or intracranial dissection
  - avoid anticoagulants as risk of bleed or subarachnoid haemorrhage (SAH)
  - consider antiplatelet agents 3-6 months to prevent further stroke (CVA)
- if extracranial dissection and small stroke area and no SAH:
  - consider anticoagulation or antiplatelet Rx for 3-6 months
if extracranial, consider vascular opinion for repair or stenting, particularly if recurrent transient ischaemic attack (TIA) on antiplatelet Rx
avoid:
- contact sports
- chiropractic neck manipulation
- any activity that involves abrupt rotation and flexion-extension of the neck