Stroke and Tias (Transient Ischaemic Attacks)

INTRODUCTION

A stroke is a focal neurological deficit lasting longer than 24 hrs and is caused by a vascular phenomenon (intracerebral haemorrhage or infarction).

A transient ischaemic attack (TIA) is a transient episode of neurological dysfunction caused by focal brain or retinal ischaemia without infarction.

A stroke in evolution is an enlarging neurological deficit, presumably due to infarction, that is increasing over 24–48 h.

The common causes of stroke are 1° intracerebral haemorrhage (10%); SAH 5% and ischaemic stroke 85%.

STROKE

Key messages

• Treat all TIAs and strokes as emergencies and admit to specialised stroke units with imaging facilities (CT and/or MRI), esp. if the unit provides thrombolytic therapy (if possible) for ischaemic stroke

• There is a 4.5-hour absolute time frame from onset of stroke for thrombolytic therapy to be effective

• Use the FAST mnemonic: Face (ask person to smile), Arms (raise both arms), Speech (say a simple sentence), Time to intervention 3–4 hrs (ideal)

Three proven strategies to improve outcome of acute stroke (level 1 evidence):

• giving IV plasminogen activator (rtPA) within 4–4.5 h for ischaemic stroke

• giving antiplatelet agents within 48 hrs of ischaemic stroke

• management in a stroke unit

Practice points

• CT (or MRI—preferred if available) scan is ordered on all these patients: if normal repeat in 7–10 d; non-contrast CT scan is the emergency investigation of choice

• Cardiac disease is a common source of emboli

• Consider possibility of a patent foramen ovale (in 20% population) in younger people (paradoxical emboli: veins → brain)

• Sudden stroke is typical of embolism

• Carotid and transcranial US (or an MRI) is used to investigate carotid artery and posterior circulation (Fig. S3)

Management (best in stroke unit)

• Investigation incl. identification of risk factors

• Treat hypertension vigorously and other risk factors, e.g. ↑ cholesterol

• IV fluid, electrolyte and nutritional support

• Physiotherapy and speech therapy

• Vigorous rehabilitation with a multidisciplinary team

• Intracerebral haemorrhage (tends to ‘grow’): consider surgical evacuation for cerebellar and cerebral white matter haemorrhage

• SAH: nimodipine ± surgery

• Infarction:

  • – thrombolytic therapy with rtPA (alteplase) within 4–5 hrs

  • – antiplatelet agents, e.g. aspirin 150–300 mg (o)/d within 48 hrs if no haemorrhage

  • – heparin not recommended (avoid steroids, mannitol and anticoagulants)

  • – consider clot extraction, esp. ICA, MCA occlusion (but after rtPA)