Cerebral Infarction (Clinical) Flashcards
What is the definition of a stroke?
The sudden onset of focal or global neurological symptoms caused by ischemia or hemorrhage and lasting more than 24 hours.
About 85% of strokes are ischemic.
What is a transient ischaemic attack?
TRANSIENT ISCHEMIC ATTACK (TIA)
is the term used if the symptoms resolve within 24 hours.
Most TIAs resolve within 1-60 min.
What are the causes of ischaemic stroke?
Larger artery atherosclerosis
Cardioembolic (e.g atrial fibrillation)
Small artery occlusion (lacune)
Undetermined/cryptogenic
Rare causes (arterial dissection, venous sinus thrombosis)
What are the haemorrhagic causes of stroke?
Primary intracerebral hemmorhage - no tumour or aneurysm (may be as a result of high blood pressure or amyloid angiopathy)
Secondary haemorrhage (subarachnoid haemorrhage, arteriovenous malformation)
Define ischaemic penumbra
The area surrounding an ischaemic event
What is the result of anoxia on cells?
Infarction - complete cell death leading to necrosis
How can further damage result from a stroke?
Edema (depending on size and location of the stroke)
Secondary haemorrhage into the stroke
What are the stages of pathogenesis of ischaemic stroke?
What are the non-modifiable risk factors for stroke?
–Previous stroke
–Being old
–Being male
–Having a horrible family history
- Diabetes
What are modifiable risk factors for stroke?
Hypertension
Smoking
Cholesterol
Diet
High BMI
Sedentary
Alcohol
What is the most important modifiable risk factor for stroke?
Hypertension
What is the problem with chronic high blood pressure?
•Chronic hypertension worsens atheroma and affects small distal arteries.
Also a major risk factor in haemorrhagic strokes
Why does increased serum lipid increase stroke risk?
Due to blood vessel wall atheroma
What is the result of increased plasma level of LDL?
Excessive amounts of LDL within the arterial wall
What is the effect of hypertension, cigarette smoke and diabetes on LDL-C?
•Hypertension, cigarette smoke, and diabetes contribute to LDL-C deposition in arterial walls.
How does alcohl affect stroke risk?
Small amounts of alcohol reduces stroke risk
Heavy drinking increases stroke risk by 2.5 fold
What is the result of obesity on vascular disease?
Risk factor for vascular disease including stroke (especially abdominal obesity)
Other important risk factors
Imparied cardiac function (recent heart attack, atrial fibrilaltion)
Oral contraceptives (+HRT) with a high estrogen content. Progesterone only ok
Hypercoagulable states: malignancy, genetic
What comprises the anterior circulation of the brain?
2 internal carotid arteries
2 anterior cerebral arteries
2 middle cerebral arteries
What comprises the posterior circulation of the brain?
2 vertebral arteries - 1 bassilar
3 pairs of cerebellar arteries
2 posterior cerebral arteries
What are symptoms of ACA occlusion?
Contralateral:
Paralysis of foot and leg
Sensory loss over foot and leg
Impairment of gait and stance
What are the symptoms of MCA occlusion?
Contralateral
- Paralysis of face/arm/leg
- Sensory loss of face/arm/leg
- Homonymous hemianopia
Gaze paralysis to the opposite side
Aphasia if stroke on dominant (left side)
Unilateral neglect and agnosia for half of external space if non-dominant stroke (usually right side)
Agnosia - inability to interpret sensations and hence to recognise things
Whcih part of the optical tract will a lesion cause a problem in 1 eye and 2 eyes?
Anything in front of the optic chiasm is a on eye problem
Behind the optic chiasm it is a two eye problem
Left hemisphere lesion
Hemiplegia, homonymous hemianopia, dysphasia
Right hemishphere lesion
Visual agnosia
Sensory agnosia
Anosagnosia (denial of hemiplegia)
Prosopagnosia (failure to recognise faces)
What type of stroke affects the basal ganglia?
Lacunar stroke
What are lacunar stroke syndromes?
No Cortical signs (dysphasia, neglect, hemianopia)
- Pure motor stroke
- Pure sensory stroke
- Dysarthria - Unclear articulation of speech
- Ataxic hemiparesis (weakness/clumsiness likely to be of the leg)
Which part of the brain is associated with the posterior circulation of the brain?
Brainstem
Cerebellum
Thalamus
Occipital and medial temporal lobes
What are symptoms of brainstem dysfunction?
- Coma, vertigo, nausea, vomiting,
cranial nerve palsies, ataxia.
- Hemiparesis, hemisensory loss
- Crossed sensori-motor deficits
- Visual field deficits
What are treatments for stroke?
TPA - tissue plasminogen activator
Wo is part of the multidisciplinary team in the 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)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
Look
Note that the lacunar stroke doesn’t have the 3rd box down because it is ‘devoid’ of cortical signs
What stroke si the most lethal?
TACS
What is the criteria before administering TPA?
Less than 4.5 hours from symptom onset
Disabling neurological defecit
Symptoms presont for more than 60 minutes (ensures it isn’t a TIA)
Consent
What is the exclusion criteria for IV TPA?
Anything that increases the possibility of haemorrhage:
Blood on CT
Recent surgery
Recent episodes of bleeding
Coagulation problems
BP is greater than 185 systolic or greater than 110 diastolic
Glucose is less than 2.8 or greater than 22mmol/l
How does the effectiveness of TPA change over time?
After 6 hours you can’t be sure thrombolysis is of any benefit
What is the alternative to medical treamtment of stroke
Surgical - endovascular treatment
What is the stroke recurrence rate within the first 2 weeks of a TIA
10%
What are the likely treatments after a TIA occurs?
Antiplatelets
Antihypertensives
Statins + endarterectomy
What are the investigations for stroke?
ESR is an inflammatory molecule
What is secondary prevention for stroke?
What are the differentials for stroke?
Bells palsy
Intracranial mass
Migraine
What are the objectives of stroke care?
Reduce mortality
Reduce disability
Improve psychological status
Improve knowledge
Maximise quality of lofe
