Stroke Flashcards
Define stroke
Acute neurological condition in which arterial blood supply to brain tissue is impaired due to a focal vascular cause - >24 hours
What % of strokes are classified ischaemic strokes?
85%
Define ischaemic stroke
Cerebral infarction due to insufficient cerebral blood flow (hypoperfusion) - leads to ischaemia and neuronal injury
What % of strokes are classified haemorrhagic strokes?
15%
3 subtypes of haemorrhagic strokes
- Intracerebral (parenchyma)
- Intraventricular (ventricles) - can be primary or secondary
- subarachnoid (subarachnoid space)
What % of strokes are subarachnoid haemorrhages
5%
Stroke epidemiology
- 3-5th leading cause of death, and the leading cause of morbidity
- M > F
- 2/3 patients 65 years or older
- Overall incidence of stroke mortality and morbidity has decreased over the past few decades
5 broad causes of ischaemic stroke
- Cardioembolic (25%)
- Lacunar infarction (small vessel disease) (15%)
- Intracranial atherosclerosis (10%)
- Extracranial atherosclerosis (10%)
- Other (40%)
Describe large artery atherosclerosis
- Usually secondary to hypertension
- Includes carotid artery stenosis
Describe cardioembolism
- Causes include AF, myocardial infarction, infection and atheroemboli
Describe small vessel occlusion
- Includes lipohyalindric thickening of small vessels
- Hypertension and diabetes are the main causes
What is a Watersed stroke?
Systemic hypoperfusion causing stroke
- Border-zone infarct
- Increased HR, decreased BP, palor, diaphoresis
- Bilateral symptoms - visual loss, proximal limb weakness
- Diffuse neurological deterioration
What is the strongest single predisposing factor for both ischaemic and haemorrhagic stroke
Arterial hypertension
Stroke risk factors
- Increased age
- Male
- African-American/Native American/Hispanics
- Family history (CVD or cerebrovascular disease)
- Arterial hypertension
- Atherosclerosis
- Hypercholestrolaemia
- DM
- Obesity
- Stress
- Alcohol
- Tobacco
- Illicit drugs
- CVD
- OCP/hormones
Main risk factors for intracerebral haemorrhage
- Hypertension
- Cerebral amyloid angiopathy
- Ruptured AV malformation
Risk factors for subarachnoid haemorrhage
- Ruptured aneurysm (circle of Willis) (80% berry)
- Ruptured AV malformation
- Traumatic brain injury
Clinical features of stroke
*** Symptoms depend on location of stroke
- Sudden onset
- Impaired consciousness
- Nausea and vomiting
- Headache
- Seizures
Which type of stroke has more distinct/unique clinical features
Subarachnoid haemorrhage
Unique clinical features of subarachnoid stroke
- Sudden severe headache
- Worsening nausea and vomiting
- Cardiovascular deterioration
- Unconscious/coma
- Neck stiffness
- Pupils not reactive to light
Clinical features - affected MIDDLE CEREBRAL ARTERY
- Contralateral sensory loss
- Paralysis - arms, lower face, legs
- Gaze - towards infarct side
- Aphasia
Clinical features - affected ANTERIOR CEREBRAL ARTERY
- Contralateral paralysis - Lower > Upper
- Minimal sensory loss
- Dysarthria
- Dyphasia
- Urinary incontinence
- Abulia (lack motivation)
Clinical features - affected POSTERIOR CEREBRAL ARTERY
- Visual field defects
- Contralateral hemisensory loss
- Memory deficits
- Vertigo
- Nausea
Clinical features - affected COMMON CAROTID
- Horner’s syndrome
Define lacunar stroke
- Ischaemic stroke
- Blood flow to one of the small arteries deep within the brain becomes blocked
- 1/5 all strokes
- Found in deep cerebral white matter, basal ganglia or pons
Initial evaluation of possible stroke
- Risk factors
- Signs of an affected vessel/area
- Onset of symptoms
- Rule out other causes of neurological deficits and AF (using ECG)
- FBC, coags, electrolytes, troponin
Imaging for suspected stroke
- Non-contrast CT (gold-standard) (can see acute haemorrhage)
- MRI (identifies earlier than CT)
Occluded vessels on CT - appearance
- Hyperdense
- Parenchyme hypodense
- Loss of corticomedullary differentiation
CT - 12-24 hours post ischaemic stroke
- Hypodense
CT - many days post-ischaemic stroke
- Hyperdense
Neurovascular studies for stroke
CTA/MRA - CT/MRI angiogram
- Find exact location of defect
Lumbar puncture and stroke
- Definitive diagnosis for subarachnoid haemorrhage
- Do if CT is inconclusive
- Yellow or red discolouration
- Increased or no change in opening pressure
- Normal glucose
- Increased RBC/WCC/protein
Pan necrosis
- Death of all cells
- Complete or permanent ischaemia
Selective neuronal necrosis
- Hypoxia induced selective destruction of individual nerve cells
- Ischaemia with subsequent reperfusion
DDx for ischaemic stroke
- Seizure
- Metabolic disorders - eg. hyponatraemia, hypoglycaemia
- Migraine aura
- Systemic infection
- Brain infection
- Brain tumour
- Psychiatric conversion disorder
- Peripheral vestibulopathy
- Traumatic intracranial injury
Initial supportive management for stroke
- Resus - fluid replacement, sufficient oxygen, maintain BGL, analgesia
- Control elevated intracranial pressure/cerebral oedema
- Monitor for signs of brain herniation (elevate head 30 degrees and IV mannitol)
- Maintain sufficient cerebral perfusion (anti-HTN and cardiac monitoring)
TREATMENT
- Ischaemic stroke
- No cerebral venous sinus thrombolysis
- <4.5 hours, no thrombolysis contraindications
1. Alteplase (r-tPA) \+ Aspiring 24 hours later \+ Endovascular intervention \+ Supportive care and swallowing assessment \+ VTE prophylaxis and early mobilisation
TREATMENT
- Ischaemic stroke
- No cerebral venous sinus thrombolysis
- > 4.5 hours, thrombolysis contraindcated
- Aspirin
+ Supportive care and swallowing assessment
+ VTE prophylaxis and early mobilisation
TREATMENT
- Ischaemic stroke
- Central venous sinus thrombosis
- Anticoagulation (eg. Warfarin, Heparin)
+ Supportive care and swallowing assessment
TREATMENT
- Haemorrhagic
- Neurosurgical and neurocritical care evaluation
+ Admission to ICU or stroke unit
+ Airway protection (endotracheal intubation)
+ Aspiration precautions
*** Often need intubation and invasive monitoring of BP
Predicted haemorrhagic stroke and pyrexic
- Paracetamol
- Cooling blankets
If on pre-existing warfarin with predicted haemorrhagic stroke
- Cease warfarin
- Phytomenadione
- Fresh frozen plasma OR prothrombin complex concentrate
- Platelet transfusion
If on pre-existing heparin with predicted haemorrhagic stroke
- Cease heparin
- Protamine sulfate
- Platelet transfusion
If on pre-existing dabigatran with predicted haemorrhagic stroke
- Cease dabigatran
- Idarucizumab
Predictor lobar haemorrhage stroke treatment
- Anticonvulsants - Phenytoin
- Seizures complicate acute intracranial haemorrhage management
Prognosis ischaemic stroke
- Leading cause of serious LT disability
- Prognostic scores - ASTRAL and iScore
- 1990-2010 - decreased mortality by 14-37%
- Better outcomes with tPA
Complications with ischaemic stroke
- DVT
- Seizure
- Haemorrhagic transformation
- Oedema (due to tPA)
- Brain oedema and increased intracranial pressure
- Depression
- Aspiration pneumonia
Prognosis haemorrhagic stroke
- Mortality 35-40% (much higher than ischaemic)
- > 70% severe morbidity
- Haemorrhagic volume is the strongest predictor of outcome
- Worse outcomes - increased age, increased consciousness on presentation, ruptured haematoma into ventricular system
- Intracerebral haemorrhage score - 3-month functional outcomes
Complications with haemorrhagic stroke
- DVT
- Infection
- Seizures
- Delirium
- Hydrocephalis
