A stroke is a sudden onset of brain dysfunction due to alterations in cerebrovascular blood supply. It is acute in onset and presents with focal neurological deficits (95% of the time).
The difference between a stroke and a transient ischaemic attack (TIA) is that a TIA is temporary and resolves within minutes to hours. A stroke is present if neurological signs last for more than 24 hours.
It peaks at 70+ years of age.
Definition of terms
| Term | Definition |
|---|---|
| Transient ischaemic attack | This is essentially a ‘minor stroke’. It presents with stroke like symptoms which completely resolve within 24 hours. It is usually the result of micro-emboli (80%), but may be also be caused by mass lesions and massive postural hypotention. |
| Completed stroke | The clinical effects of stroke have reached their maximum (usually within 6 hours of onset) |
| Stroke in evolution | Describes the progress of stroke in the first 24 hours |
| Amaurosis fugax | Transient, sudden, painless loss of vision in one eye caused by temporary lack of blood flow to the retina |
| Transient global amnesia | Sudden, temporary episode of profound anterograde amnesia, often accompanied by mild retrograde amnesia with no other neurolgoical deficits |
Presentation of stroke
| Category | Presentation |
|---|---|
| Suggests hemorrhage (unreliable) | Meningism, severe headache, and coma |
| Suggests ischaemia | Carotid bruit, atrial fibrillation, history of TIA, and ischemic heart disease |
| Suggests cerebral infarction (50%) | Contralateral sensory loss, contralateral hemiplegia (flaccid then spastic), dysphasia, homonymous hemianopia, and visuo-spatial defects |
| Suggests brainstem infarction (25%) | Quadriplegia, gaze, vision and balance disturbance, land ocked-in syndrome |
| Suggests lacunar infarction (25% – basal ganglia, internal capsule, thalamus, and pons) | Ataxic hemiparesis, pure motor loss, pure sensory loss, sensorimotor loss, dysarthria, involuntary movements (clusmy hand), impaired cognition and consciousness in thalamic stroke |
- Risk factors for stroke
- Hypertension (#1 risk factor, RR = 3 – 5)
- Heart disease (RR = 2 – 4)
- Atrial fibrillation (RR = 5 – 18)
- Diabetes mellitus (RR = 1.5 – 3)
- Smoking (RR = 1.5 – 3)
- Alcohol use (RR = 1 – 4)
- Older age
- Family History of Stroke
- Past History of Stroke
- Dyslipidemia
- Cerebral aneurysm
- Obesity
- Signs and symptoms
- Facial drooping
- One-sided weakness of the arm or leg
- Verbal deficit: slurring, dysarthria, aphasia, verbal agnosia
- Altered level of consciousness
- Differential diagnosis
- Head injury
- Hypoglycaemia or Hyperglycaemia
- Subdural hemorrhage
- Focal-onset seizure with Todd’s paralysis
- Intracranial neoplasm
- Wernicke’s encephalopathy
- Hepatic encephalopathy
- Toxoplasmosis
- Encephalitis
- Cerebral abscess
- Complicated migraine
- Investigations
- Non-contrast CT to distinguish and ischemic from a hemorrhagic stroke. It takes 6 hours for the CT scan to develop hypodensities. A hyperacute stroke can present with a normal head CT. It shoudl be repeat in 3 days
- Dense MCA sign is seen in MCA occlusion
- Dense Basilar artery is seen in basilar artery occlusion
- Haemorrhagic stroke presents with hyperdensity (corresponding to blood)
- Brain MRI without contrast after acute treatment. ****
- DWI sequence is the gold standard (water cannot diffuse within infarcted tissue and shows hyperintensity).
- DWI is checked against the ADC sequence.
- Vacular imaging
- CT angiography of the head with contrast in emergency cases. Carries risk of contrast nephropathy and is susceptible to bone artefacts
- MR angiography of the head with/without gadolinium in non-emergency cases or patient that should not be repeatedly radiated. Gadolinium can be used in the workup for intracranial hemorrhage.
- Carotid Doppler for blockage
- Blood Glucose to exclude hypoglycemia, which can mimic stroke
- Coagulation profile for PT and INR.
- Electrocardiogram for A-fib
- Echocardiogram for intraventricular or intraatrial thrombi, dilated cardiomyopathy and valvular heart disease
- Lipid panel for LDL
- Complete blood count for platelets
- Non-contrast CT to distinguish and ischemic from a hemorrhagic stroke. It takes 6 hours for the CT scan to develop hypodensities. A hyperacute stroke can present with a normal head CT. It shoudl be repeat in 3 days
- Treatment
- 7 S’s
- Significant history and Systemic anticoagulation (stroke risk factors and last dose of anticoagulant)
- Symptom onset time (time last normal for viable brain tissue)
- Symptoms and deficits (for targeted neurological examination)
- Systolic blood pressure (may need to be adjusted)
- Sinus rhythm (A-fib may be present)
- Stroke laboratory investigations (CBC, RBS, UEC, LFTs, coagulation panel)
- Stroke scale (NIH stroke scale to screen for disabling deficits and localize lesions)
- Secure Airway to prevent aspiration and hypoxia
- Supplemental Oxygen if SpO2 < 94%
- 2 Large bore IV access
- Control Blood Pressure immediately if > 220 mmHg systolic
- Generally aim for ≤ 185/110
- Reduce MAP by 15% in the first 24 hours for acute ischemic stroke without fibrolysis
- Reduce MAP by 15% over 1 hour for acute ischemic stroke with fibrolysis
- Target 140 systolic within the first 24 hours in Haemorrhagic stroke
- Maintain homeostasis
- Treat hypoglycemia if < 4.4 mmol/L
- Antipyretics (Acetaminophen) if Temperature is > 38 C
- Nil per oral until the patient is screened for swallowing
- High-dose aspirin once hemorrhagic stroke is excluded
- Admissios to the ICU or stroke unit
- 7 S’s
- Primary prevention
- Control risk factors (hypertension, diabetes, hyperlipidaemia and cardiac disease)
- Smoking cessation
- Exercise (increases HDL and glucose tolerance)
- Anticoagulation in atrial fibrilation and prosthetic valves
- Secondary prevention
- Control risk factors as in primary prevention
- Daily antiplatelets after stroke
- Anticoagulation after stroke from atrial fibrillation