Stroke Presentation and Investigation Flashcards
What percentage of NHS beds are occupied by stroke patients?
20%
What is a stroke?
A neurological deficit of sudden onset, lasting more than 24 hours, of vascular origin
What is a transient ischaemic attack?
A neurological deficit of sudden onset and vascular origin but lasting less than 24 hours
What causes stroke?
Occlusion of a blood vessel by thrombus or embolus
Haemorrhage from rupture of a blood vessels
What percentage of strokes are ischaemic and what percentage are haemorrhage?
85% ischaemic
15% haemorrhagic
What are the symptoms of stroke?
Loss of; Power Sensation Speech Vision Coordination
What areas of the brain are supplied by the carotid system?
Most of the hemispheres and cortical deep white matter
What areas of the brain are supplied by the vertebro-basilar system?
Brain stem, cerebellum and occipital lobes
What are the potential causes of a stroke?
Vessel occlusion
Disease of vessel wall
Disturbance of normal properties of blood
Rupture of vessel wall
What are the main causes of an ischaemic stroke?
Large artery atherosclerosis (35%)
Cardioembolic e.g. atrial fibrillation (25%)
Small artery occlusion (25%)
Undetermined/cryptogenic (10-15%)
Rarer causes e.g. arterial dissection (<5%)
What are the main causes of haemorrhagic stroke?
Primary intracerebral haemorrhage (70%)
Secondary haemorrhage e.g. subarachnoid haemorrhage, arteriovenous malformation (30%)
What are the stroke subtypes?
TACS - total anterior circulation stroke
PACS - partial anterior circulation stroke
LACS - lacunar stroke
POCS - posterior circulation stroke
What are the features of TACS?
20% of strokes Patient usually has; weakness, sensory deficit, homonymous hemianopia
and higher cerebral dysfunction e.g. dysphasia
What are the features of PACS?
35% of strokes
2 of the 3 TACS criteria (weakness, sensory deficit,
homonymous hemianopia)
or
restricted motor/sensory deficit e.g. one limb, face and hand or higher cerebral dysfunction alone
What are the features of LACS?
20% of strokes
Can be pure motor, pure sensory, sensorimotor, or ataxic hemiparesis
What are the features of POCS?
25% of strokes
Affects brainstem, cerebellar or occipital lobes
Variable and frequently complex presentation
What are the risk factors for stroke?
Hypertension Atrial fibrillation Age Race Family history
What is alteplase?
Firbinolytic agent
What can alteplase cause in the brain if there is established tissue damage?
Unexpected bleeding
Can also cause bleeding elsewhere e.g. in the gut
Patients admitted with a stroke within 4.5 hours of definite onset of symptoms should be treated with what?
0.9mg/kg intravenous rtPA (alteplase)
IF considered suitable
Onset to treatment should be minimised with earliest possible delivery of IV rtPA within time window
When should streptokinase not be used?
For treatment of patients in the acute phase of stroke
Where should thrombolysis be administered?
Within an acute stroke service
According to NICE guidelines, what should patients with a suspected stroke have?
Ambulance priority in appropriate cases Rapid triage on hospital arrival Immediate access to specialist stroke services Rapid brain imaging Rapid specialist assessment
What are the contraindications to thrombolysis?
Age - most RCTs have excluded < 16 and > 80 y/o
Recent bleeding
Severe hypertension
What percentage of patients benefit from admission to a stroke unit in acute stroke treatment?
90%
What percentage of patients benefit from thrombolysis within 0-3 hours in acute stroke treatment?
10% ischaemic strokes
What percentage of patients benefit from aspirin in 0-48 hours in acute stroke treatment?
65% ischaemic
What percentage of patients benefit from hemicraniectomy in acute stroke treatment?
0.5%
Why are stroke units beneficial?
Well established evidence that patients do better up to 10 years after admission
Mobilise patients ASAP
Concentrate on simple but important things e.g. swallowing, positioning - swallowing problems present in 50% of stroke patients
Early therapy
Concentrated stroke expertise
What is the effect of early mobilising in stroke patients on the probability of them returning home?
Probability of returning home decreases by 20% for each day that the patient is not moved
What is the risk of early recurrent stroke in TIA and stroke?
Identical risk of early recurrent stroke - up to 14% within the first two weeks
What fraction of people who have a TIA will have an acute stroke in the future?
1/3
What is the stroke patient risk of recurrent event at 7 days, 30 days and 3 months?
7 day stroke risk 11.5%
30 day stroke risk 15%
3 month stroke risk 18.5%
What is the TIA patient risk of recurrent event at 7 days, 30 days and 3 months?
7 days stroke risk 8%
30 day stroke risk 11.5%
3 month stroke risk 17.3%
What effect can early initiation of preventative treatment following TIA have on the risk of recurrent stroke?
Can reduce the risk of early recurrent stroke by 80%
For patients with a TIA, what is evaluation and initiation of treatment in a specialist outpatient clinic associated with?
Reduced risk of subsequent stroke
What can be done for primary prevention of a stroke?
Thrombolysis
Aspirin
Hemicraniectomy
Admission to stroke unit
What can be done for secondary prevention of a stroke?
Clopidogrel 75mg or aspirin 75mg plus dipyridamole MR 200mg BD Statin Hypertension drugs (even if BP is within normal range)
What should be done in phase 1 (0-30 months) of stroke treatment?
Daily appointment clinic
Treatment advice faxed to GP
What should be done in phase 2 (30-60 months) of stroke treatment?
Emergency access to clinic
Treatment started in clinic
What is the effect of carotid endarterectomy on the risk of stroke or death?
In 50-69% stenosis, risk of stroke or death is reduced by 7-9% at 5 years after surgery
In > 70% stenosis, risk of stroke or death is reduced by 14-19% at 5 years after surgery
When is surgery for carotid stenosis done?
Anterior circulation stroke
TIA or stroke with good recovery
70% occlusion
What are the necessary details to obtain from the history of a stroke?
Time of onset Witnesses Headache, vomiting, neck stiffness or photophobia - suggest haemorrhage Loss of consciousness Fit Incontinence
What are the signs of a stroke on neurological history/examination?
Motor - clumsy or weak limb Sensory - loss of feeling Speech - dysarthria, dysphasia Neglect or visuospatial problems Vision loss in one eye or hemianopia Gaze palsy Ataxia, vertigo, incoordination or nystagmus
What is localisation useful for in stroke diagnosis?
Confirms diagnosis
Allows better selection of imaging
Gives an indication of cause
Gives an indication of prognosis
What tests are done in the investigation of stroke?
Blood tests - FBC, lipids ECG, 24 hour ECG CT MRI Carotid Doppler Echocardiogram may be useful
What are the benefits of CT and MRI?
CT is quick and will show blood
MRI takes up to 30 minutes and can be claustrophobic but will show an ischaemic stroke better than a CT
