Stroke

Stroke

May 23, 2018 0
General medicine,neurology,onthepods

James discusses an approach to stroke with Dr Alice Ma. A stroke is an acute neurological deficit that lasts for more than 24 hours and is caused by cerebrovascular aetiology.

Summary Writer:  Dennis Neuen

Script Writer:  Barath Arunasalam

Editor:  Alice Ma

Interviewee:  Alice Ma

About Dr Alice Ma

Alice Ma graduated from the University of Sydney Medical School in 2010. She has trained in ICU and Neurology. Alice is currently the neurointerventional fellow at Royal North Shore Hospital with a particular interest in stroke and endovascular clot retrieval.

Stroke

With Dr Alice Ma, Neurointerventional Fellow at Royal North Shore Hospital, Sydney, Australia

Introduction

A stroke is an acute neurological deficit that lasts for more than 24 hours and is caused by cerebrovascular aetiology. The risk of stroke is associated with increased age, previous stroke or transient ischaemic attack, hypertension, smoking, diabetes mellitus (DM), hypercholesterolaemia and atrial fibrillation/flutter (AF). A potential stroke is a time-critical clinical situation that requires urgent assessment with appropriate investigation and escalation to prevent long-term deficits and complications.

Case 1

You are a junior doctor on the ward and the nursing staff have asked you to review a patient that has become confused. You wonder whether it could be related to recent oxycodone administration, but upon reviewing the patient, you notice some dysarthria and facial droop.

  • What is the neurological deficit?
  • What was the patient like prior and what has changed now?
  • Nursing staff and family have good insight to answer this and may have witnessed symptom onset.
  • History
    • Onset of symptoms, or if not well established, the “last known well” time
    • Collaborative history is important, from both nursing staff and family
    • Past medical history
      • Particularly in relation to thrombolysis contraindications – e.g. prior intracerebral haemorrhage (ICH), active bleeding risk (anticoagulant or antiplatelet agents)
  • Examination
    • Targeted neurological examination
      • Many important examination findings are not obvious; you need to specifically examine
      • It may be difficult to differentiate between acute confusion and dysphasia at the bedside
    • Motor deficit – common in large vessel or lacunar strokes
      • Asymmetry and weakness can be subtle
      • Remember to test for “drift” in upper and lower limbs – a positive result if there is downward drift after holding arm up for 10 seconds in arms and 5 seconds in legs
    • Sensory deficit
    • Cerebellar deficit
    • Parietal stroke – sensory neglect: check bilateral simultaneous stimulation of face, arm and leg
    • Occipital stroke – visual field and acuity changes
    • Frontal strokes – gaze deviation
    • Assessment of severity: the National Institute of Health Stroke Scale (NIHSS) is a standardised tool commonly used and useful in communicating quickly with other health professionals
  • Primary investigation is a non-contrast CT brain to establish:
    • Ischaemic vs. haemorrhagic – 80% of strokes are ischaemic
    • Areas of established infarct – unsalvageable areas and cause of neurological deficit
    • Signs of large vessel occlusion
  • CT-angiography
    • If a patient has history suggestive of a large vessel occlusion; this normally would progress straight to CT-angiography and further advanced imaging like CT Perfusion
  • MRI
    • Can be helpful for certain patients
    • Provides much more sensitivity in early stroke and can detect other abnormalities
    • However, it is limited by time, availability and contraindications
  • Other testing is required; however, the priority is on rapid imaging as that will determine management
    • Other investigations often can wait,be done simultaneously or may become priorities if the patient is clinically unstable –CXR, ECG, bloods
  • Common stroke mimics
    • Bell’s palsy
      • In early stages, may not have full frontalis muscle involvement – therefore behaves like an upper motor neuron lesion
      • Differentiating factors: normally not a sudden onset, no other neurological deficits
    • Migraine
      • Particularly hemiplegic migraine
      • History is important, recurrent migraine and family history of migraine can help differentiate
      • Remember to test for “drift” in upper and lower limbs
  • Commencing management early is critical as every minute can result in neuronal death
    • Escalation to a stroke call or to seniors is essential if you are concerned
    • Think of a stroke as a cardiac arrest of the brain
    • The shorter time to treatment, the better the outcome
  • Thrombolysis
    • 5 hours is the cut-off time (clear evidence), which includes starting the infusion
    • If unsure about time of onset of symptoms, it is the time when “last seen well” – including for wake-up strokes
  • Thrombectomy (clot retrieval)
    • New evidence suggests that clot retrieval will improve outcomes even up to 24 hours after “last seen well” time in clinically significant strokes carefully selected using certain criteria
    • However, the evidence and guidelines regarding this are constantly evolving
  • Blood pressure management
    • Ischaemic
      • Hypertension is a way that the body responds in acute phase so can often tolerate blood pressure of up to 200mmHg systolic
      • After thrombolysis, this target will decrease and even further post-thrombectomy to prevent haemorrhagic transformation
    • Haemorrhagic
      • Controversial area with ongoing trials
      • Hypertension and hypotension is problematic
      • Tend to aim systolic <140mmHg unless there is another reason not to
  • Neurosurgical intervention for intra-parenchymal bleed
    • Decompressive craniectomy may be needed if mass effected is significant or if severe deterioration (drowsy or substantial midline shift)
  • Multidisciplinary team
    • Stroke units
      • Doctors, specialised nurses, speech pathologists, occupational therapists, physiotherapists
      • Good evidence that stroke units make substantial difference to outcomes, particularly in addressing complications
  • Complications
    • Swallowing
      • Main risk of impaired swallowing is aspiration pneumonia
      • Most stroke patients will be nil by mouth until assessed formally
      • May require NG tubes for feeding
      • Posterior circulation strokes affecting bulbar function have greatest risk
  • Recovery time
    • Rehabilitation is critically important for recovery, to allow forneuroplasticity
    • Most patients will significantly improve generally from the 12 hour mark to several weeks post-stroke
    • They often continue to improve up to 18 months; however maximal improvement is during 3-6 month post-stroke phase
  • Stroke is a time-critical emergency
  • Think of it like a cardiac arrest of the brain – every minute can result in neuronal death
  • Escalate your concerns – most hospitals have a formalised pathway for this or call a rapid response
  • Many neurological examination findings are not obviously evident without a focused exam

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Tags: #acute neurological deficit,#cerebellar deficit,#cerebrovascular aetiology,#differential diagnosis,#dysarthria,#facial droop,#frontal strokes,#haemorrhagic,#ischaemic,#neurology,#NIHSS,#occipital stroke,#parietal stroke,#sensory deficit,#stroke,#stroke risk,#thrombectomy,#thrombolysis,#transient ischaemic attack

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