Stroke Flashcards
75% of strokes occur in people of what age?
> 65 years old
Stroke risk increases with age
How many people die within 1 year of a stroke?
1/3
How many stroke survivors remain dependent on others for daily activities?
50%
What is stroke?
The SUDDEN onset of FOCAL or global neurological symptoms caused by ISCHAEMIA or HAEMORRHAGE and lasting more than 24 hours
What percentage of strokes are ischaemic?
85%
What is transient ischaemic attack (TIA)?
The term used if symptoms resolve within 24 hours
Most TIAs resolve within 1-60 min
What are the main causes of Ischaemic stroke?
- Large artery atherosclerosis (e.g. Carotid) 35%
- Cardioembolic (e.g. AF) 25%
- Small artery occlusion (Lacune) 25%
- Undetermined/Cryptogenic (10-15%)
- Rare causes
What are the main causes of Haemorrhagic stroke?
Primary intracerebral haemorrhage 70%
Secondary haemorrhage 30%
- Subarachnoid haemorrhage
- Arteriovenous malformation
Describe hypoxia to the brain
The failure of cerebral blood flow to a part of the brain
Caused by an interuption of the blood supply to the brain
Can be transient (as in TIA)
Results in varying degrees of hypoxia
What can hypoxia do to the brain?
Hypoxia stresses the brain cell metabolism. This is especially important in the ischaemic penumbra
If prolonged the hypoxia -> anoxia (no oxygen)
What does anoxia cause in brain tissue?
Anoxia -> infarction (complete cell death, leading to necrosis). This is a stroke
Apart from infarction how can further damage result during a stroke?
Oedema, depending on the size and location of the stroke
Secondary haemorrhage into the stroke
What are the non-modifiable risk factors for stroke?
Previous stroke
Being old
Being male
Having a horrible family history
What are the modifiable risk factors for a stroke?
HYPERTENSION Smoking Cholesterol Diet High BMI Sedentary lifestyle Alcohol
How is hypertension related to stroke?
Chronic hypertension worsens atheroma and affects small distal arteries
Both stroke and hypertension reach major proportions in the elderly
Hypertension is a major risk factor for haemorrhagic strokes as well
How is diabetes related to stroke?
Diabetes mellitus increases the incidence of strokes up to 3 fold in both sexes
How is smoking related to stroke?
Smokers have:
- 2 fold increase of cerebral infarction
- 3 fold increased risk of sub arachnoid haemorrhage
How are lipids related to stroke?
Increased serum lipids increase stroke risk due to blood vessel wall atheroma
Increased plasma level of LDL results in excessive amounts of LDL within the arterial wall
Hypertension, cigarette smoke and diabetes contribute to LDL-C deposition in arterial walls
How does alcohol relate to stroke?
Small amounts of alcohol decrease stroke risk
Heavy drinking increases risk 2.5 fold
How does obesity relate to stroke?
(especially abdominal)
Recently identified as an independent risk factor for vascular disease including stroke
What other medical risk factors increase likelihood of stroke?
Impaired cardiac function (recent heart attack, AF)
Oral contraceptives (+ HRT) with a high estrogen content. -Progesterone (only ok)
Hyper coagulable states
- Malignancy
- Genetic
What forms the anterior circulation of the brain?
2 internal carotid arteries
- 2 anterior cerebral arteries
- 2 middle cerebral arteries
What forms the posterior circulation of the brain?
2 vertebral arteries -> 1 basilar
- 3 pairs of cerebellar arteries
- 2 posterior cerebral arteries
What are the symptoms of ACA occlusion?
Contra-lateral
- Paralysis of foot and leg
- Sensory loss over foot and leg
- Impairment of gait and stance
What are the symptoms of MCA occlusion?
Contra-lateral
- Paralysis of face/arm/ (leg)
- Sendory loss face/arm/ (leg)
- Homonymous hemianopia
Gaze aralysis to the opposite side
Aphasia if stroke on dominant (left) side
Unilateral neglect and agnosia for half of external soace if non-dominant stroke (usually right side)
What is included in Agnosias?
Agnosias = neglect syndromes
- Visual agnosia
- Sensory agnosia
- Anosagnosia (denial of hemiplegia)
- Prosopagnosia (failure to recognise faces)
What strokes are most likely to affect basal banglia?
Lacunar strokes from the middle cerebral artery
Describe Laclunar stroke syndromes
Devoid of “cortical” signs
-E.g no dysphasia, neglect, hemianopia
- Pure motor stroke
- Pure sensory stroke
- Dysarthria - clumsy hand syndrome
- Ataxic hemiparesis
What anatomy is involved in posterior circulation symptoms?
Brain stem/ Cerebellum/ Thalamus
Occipital and medial temporal lobes
What are the symptoms of brainstem dysfunction?
- Coma, vertigo, nausea, vomiting, cranial nerve palsies, ataxia
- Hemiparesis, hemisensory loss
- Crossed sensory-motor deficits
- Visual field defects
What should acute ischaemic stroke therapies do?
Restore blood supply
Prevent extension of ischaemic damage
Protect vulnerable brain tissue
Compare NNT of different stroke treatments
IV TPA
What is TPA?
Tissue Plasminogen Activator
What are the staffing components of a stroke unit?
Clinical staff Stroke nurses Physiotherapists Speech and language therapists Occupational therapists Dietitian Psychologist Orthoptist
What is the OCSP Stroke classification?
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Lacunal Stroke (LACS)
Posterior Circulation Stroke (POCS)
What is the strict criteria for TPA use?
60 minutes
Consent obtained
What is the exclusion criteris for IV TPA?
Anything that increases the possibility of haemorrhage:
- Blood on CT scan
- Recent surgery
- Recent episodes of bleeding
- Coagulation problems
BP >185 systolic or >110 diastlic
Glucose 22mmol/L
What is the stroke recurrence from TIAs?
10% stroke recurrence within first 2 weeks
What treatments reduce the risk of stroke after a TIA?
Antiplatelets
Antihypertensives
Statins and Endarterectomy
When searching for the aetiology for stroke what should you consider?
Atherosclerotic narrowing
Embolic - cardiac sourse (AF, recent MI)
Artery to artery embolism
Hypercoaguable state
Arterial dissection
Venous sinus thrombosis
What investigations should you carry out for stroke?
Routine blood tests CT or MRI head scan ECG Echocardiagram Carotid doppler ultrasound Cerebral angiogram/ venogram Hyper-coagulable blood screen
What do you look for in routine blood tests for stroke?
FBC
Glucose
Lipids
ESR etc
What can CT or MRI head scan show in stroke?
Infarct vs haemorrhage
What can ECG show in stroke?
?AF
?LVH
What can echocardiogram show in stroke?
Valves
ASD, VSD
What can a carotid doppler ultrasound show in stroke?
?stenosis
What can cerebral angiogram/ venogram show in stroke?
Vasculitis?
What is the secondary prevention in stroke?
Anti hypertensives Anti-platelets Lipid lowering agents Warfarin for AF Carotid endeterectomy (NNT of 3)
What should you always try to rule out in suspected stroke?
Post-ictal states (e.g. Todd's paralysis) Hypoglycemia Intracranial masses Vestibular disease Bell's palsy Functional hemiparesis Migraine Demented patients with UTIs
After a stroke management should include…
Prevention of stroke recurrence
Prevention of complications related to stroke
Rehabilitation
Re-integration into the community
What are the objectives of stroke care?
Reduce mortality
Reduce residual disability amongst survivors
Improve psychological status of patients and care-givers
Improve patient/ care giver knowledge
Maximise quality of life
