Wk 2 stroke/ cerebrovascular accident and neuroplasticity
/ is upper motor neurone the afferent neurones
/hypotonia decrease resistance to PROM meaning
“with each minute of large vessel ischemic stroke untreated, close to two million neurons die”
Stroke is defined “as rapidly developing clinical signs of focal or global disturbance to cerebral
function, with symptoms lasting 24 hours or longer, or leading to death, with no apparent cause
other than of vascular origin and includes cerebral infarction, intracerebral haemorrhage, and
subarachnoid haemorrhage”
Stroke warnings
- Sudden numbness or weakness of face, arm or leg. Esp one side of the body
- Vision changes in one or both eyes
- Sudden difficultly walking, dizziness or loss of balance or coordination
- Sudden severe headache with no known cause
- Sudden confusion, trouble speaking or understanding
Modifiable
Major/ nonmodifiable risk factors
- Smoking
- Hypertension (HTN)
- Physical inactivity
- Heart disease
- Obesity
- Disorders of the heart rhythm (atrial fibrillation)
- Diet
- Elevated total blood cholesterol (HDL and LDL) / diabetes
- End stage renal disease and chronic kidney disease
- Sleep apnea (lapses in breathing)
- Gender specific: contraceptives
Common stroke deficits/ tested in neuro ax
1. Paralysis
2. Tone / ROM
3. Sensory
4. Visual
5. Cognition
6. Dysphagia (swallowing difficulties) & dysarthria (difficulty speaking- weakened muscles)
7. Ideomotor or ideational apraxia
8. Aphasia (inability to communicate – lang disorder)
Lesion in auditory association cortex in left lateral temporal
lobe
Speech flows with variety of grammatical errors
Auditory comprehension is impaired: unable to follow
commands
- Non-fluent aphasia (Broca’s/expressive aphasia)
, o Lesion located in premotor area of left frontal lobe
o Speech is slow, hesitant and vocabulary is limited/syntax is impaired
o Speech production is labored or completely lost whereas comprehension is good
Global aphasia: severe aphasia characterized by impairment in both production and comprehension
2 types of stroke:
Ischemic stroke (85%) – interruption of blood flow/ oxygen to an area of the brain
- Thrombosis: blood clot forms in a brain artery or within small blood vessels deep inside the
brain, usually forms around atherosclerotic plaques
o Endothelial cell dysfunction: inner lining of artery irritated or inflamed by e.g. toxin
in tobacco. Becomes site of atherosclerosis plaque (could take yrs to form)
-
- Embolic – Blood clot, air bubble or fat globule formed within a blood vessel elsewhere in the
body and is carried to the brain.
- Occurs blood vessels with small diameters e.g. arteriole, capillary
CPP decreases in an ischemic stroke
Haemorrhage (15%) – burst if a blood vessel
- Subarachnoid haemorrhage: bleeding from a blood vessel between the surface of the brain
(Pia) and the arachnoid tissue that cover the brain
o Often sudden onset of severe headache, vomiting and dizziness. Distorted ventricles
extended and enlarged
o Commonly due to aneurysm (weakening in blood vessel wall leading to widening
and ballooning)
- Intracerebral haemorrhage: bleeding from a blood vessel within the brain. High blood
pressure is the main cause
- AVM (arteriovenous malformation) intercranial pressure rising
Cerebral perfusion pressure - the difference between the mean arterial pressure and the
intracranial pressure. CPP= MAP – ICP (60-80 mmHg). Poststroke hypertension
- Mean arterial pressure – avg. pressure throughout one cardiac cycle. Influenced by cardiac
output and systemic vascular resistance
- Intracranial pressure – pressure within the craniospinal compartment (brain, craniospinal
fluid and blood) interventricular catheter to monitor into lateral ventricle
- Net pressure gradient that drives oxygen to cerebral tissues
- Signs of elevating intracranial pressure (ICP)
o Decreased level of consciousness (stupor or coma)
o Increased HR
o Irregular respirations (cheyne stroke resp – deep rapid breathing with long pause)
o Vomiting
o Unreactive pupils/ papilledema – swelling of both optic discs in eyes due to ↑ICP
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