Stroke Flashcards
Explain recovery from stroke
Ischaemic vs haemorrhagic recovery: each have differing mechanisms by which the body initially responds to the stroke
CNS - nerves do not have capacity for neural regeneration following an injury; patients recover via neuroplasticity
PNS - nerves do have capacity for neural regeneration following injury
What is the structure of the Circle of Willis
2 vertebral arteries - pass through transverse foramina of cervical vertebrae and join in front of brainstem → Basilar Artery; Basilar Artery divides → 2 Posterior Cerebral Arteries → connect to MCAs by 2 small Posterior Communicating arteries → back section of Circle of Willis
2 internal carotid arteries - pass in front of neck & divide to form Anterior and Middle Cerebral Arteries; 2 anterior cerebral arteries (ACAs) join anteriorly via the Anterior Communicating Artery → front section of Circle of Willis
What are other related problems in stroke patients
- Disorders of emotion - possibly affected limbic system thus hyperemotional and labile (tearful)
- Dysphagia - very common in early stroke
a. Delay / absent swallow reflex (potentially leads to food going down lungs causing aspiration pneumonia) - Incontinence - both bowel and bladder in early stages (no stimulation of muscles in bowel or bladder), where standing up may cause incontinence
- Secondary musculoskeletal problems - sublux shoulder (GH j prone to damage), other MSK problems if patient falls (incidence of falls is 40-50%)
- Balance / Gait problems
- Functional difficulties
- Social problems - particularly if they cannot communicate, life has changed post-stroke (many more limitations to socialising)
Symptoms of stroke if infarct occurs in ACAs
Anterior cerebral arteries (ACAs) supply outer and middle areas of brain:
Frontal lobe - damage will lead to significant change to movement (motor cortex at back of frontal lobe) and personality changes, loss of memory of people and events, affected ability to plan and think
Medial part of sensorimotor cortex - affecting sensation and movement
What symptoms would you get from a:
TACS – Total anterior circulation stroke
Middle and Anterior Cerebral arteries affected
All three of the following need to be present:
- Unilateral weakness (and/or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction (e.g dysphasia, visuospatial disorder)
What is the main descending pathway?
The Cortico-spinal Tract = main descending pathway - 80% fibres cross to contralateral side at medulla, synapses at alpha motor neurone at specific spinal cord level, in turn passes motor information to peripheral (lower motor nerve) motor nerve to muscle
What symptoms would you get from a:
POCS – Posterior circulation stroke ?
Cortical stroke in posterior cerebral artery, basilar artery, vertebral arteries
ONE of the following must be present:
•Cranial nerve palsy and a contralateral motor/sensory deficit
•Bilateral motor/sensory deficit
•Conjugate eye movement disorder (e.g. horizontal gaze palsy)
•Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
•Isolated homonymous hemianopia
What healthy lifestyle advice can we give to reduce these risk factors of CVD
there are a few which we can influence and we will often give advice to patients with regards to:
•Ensuring that they take BP medication as directed. Blood pressure management is very important to reduce the risk of further strokes.
• Ensuring people with diabetes have support in place to ensure they are managing their blood sugars correctly.
•Smoking cessation advice: smoking dramatically increases the risk of stroke and reduction or abstinence of smoking at any time reduces the risk accordingly.
•Healthy eating advice in order to reduce cholesterol and reduce salt intake which can positively impact maintaining healthy arteries.
•Keeping active and maintaining fitness at a level appropriate to the patient, with consideration made according to each individual patient we treat.
What is the blood supply to the brain called?
The Circle of Willis
What is the time frame in which a person must present to hospital to ensure they are able to receive thrombolysis for an Ischemic stroke?
4 hours
Where does most of the motor information originate in the brain?
Motor Cortex in the posterior Frontal Lobe
Define neuroplasticity
The adaptive capacity of the CNS and its ability to modify its own structural organisation and functioning.
Neuroplasticity refers to an array of mechanisms that contribute to neuronal reorganisation and is thought to be the underlying principle by which post stroke recovery occurs.
What are the four main symptoms of a stroke and where in the brain would damage lead to these symptoms?
- Motor - Pre-motor Area, Supplementary Motor Area and Primary Motor Cortex in the posterior frontal lobe
- Sensory - Primary Somatosensory Cortex (S1) in anterior parietal lobe adjacent to posterior frontal lobe (postcentral gyrus)
- Speech - Broca’s area (usually in left frontal lobe) Wernicke’s area (posterior superior left temporal lobe)
- Cognitive - frontal, parietal, temporal and occipital lobes
What is role of PT in stroke treatment
Primary goals are to prevent complications, minimise impairments and to maximise function
Main speech symptoms seen in stroke
- Dysarthria - slurred speech
- Expressive dysphasia = Damage to Broca’s area; Usually associated with Rt hemiplegia; Lose ability to produce speech
- Receptive dysphasia = Damage to Wernicke’s area in temporal lobe; Lose ability to understand speech
- Global aphasia - complete lack of speech
Define stroke
Also known as a cerebrovascular accident (CVA), is the rapid loss of brain function(s) due to disturbance in the blood supply to the brain. This can be due to ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism), or a haemorrhage (leakage of blood).
Seen by rapidly developing clinical signs or symptoms of focal and at times global loss of cerebral function lasting more than 24 hours or that lead to death, with no apparent cause other than vascular
What are the 9 risk factors for CVD
- Age
- Hypertension (systolic >160mmHg; diastolic >95mmHg)
- Ischaemic heart disease
- AF
- High blood cholesterol
- Diabetes mellitus
- High salt diet
- Smoking
- Contraceptive pill (containing oestrogen)
What are the 9 clinical features of stroke
Hemiparesis is a slight weakness/ loss of strength due to paralysis on one side of the body.
Hemiplegia is a severe or complete loss of strength or paralysis on one side of the body.
Spasticity “a motor disorder charcterised by a velocity dependent increase in tonic stretch reflexes that result from abnormal intra-spinal processing of primary afferent input” (Young, 2004)
Low Tone results from reduced ability of the muscle to move against gravity and produces little to no resistance to passive movement.
Receptive Dysphasia is the inability or difficulty in understanding speech.
Expressive Dysphasia is difficulty in the production of language, inability of difficulty selecting language appropriately in order to communicate.
Ataxia is the incoordination of movement and the lack of smooth, coordinated movement.
Apraxia is the loss of the ability to select and sequence fine and gross motor skills. There are different types of apraxia which affect stroke patients is different ways.
Agnosia is the inability to recognise objects and understand what objects are used for (visual, astereognosis, auditory).
Neglect is a severe inattention to affected limb or side of body affected by stroke. Includes visual avoidance of that side, in serve cases unable to turn head and eyes past mid point. Patients fail to attend to stimuli on affected side.
Meninges of the brain
Immediately covering the brain = pia (mother) mater (covering) layer; Pia mater is a very thin layer and is “mother cuddling the brain”
Next layer = arachnoid (spider appearance) mater; Arachnoid mater has all the capillaries that supply outside of the brain in this layer thus looks like spider
Final layer = dura (durable) mater; Dura mater is very robust and strong that helps to holds the brain in place
What are the two main types of stroke?
Ischaemic (80%) - Most common type of Stroke caused by a blood clot which blocks the flow of blood and therefore oxygen to brain tissue. Blood clots typically form in areas where arteries are narrowed or blocked due to as plaques as a result of atherosclerosis. Blood clots can be: atheroma of cerebral artery, thrombosis (blood clot in the brain or neck), embolism (blood clot from somewhere else that has moved and now blocks a blood vessel in the brain or neck). Classified by Bamford (Oxford) classification - according to site and extent of lesion
Haemorrhagic stroke caused by a weakened vessel that ruptures and bleeds into the surrounding brain such as a bleeding aneurysm, an arteriovenous malformation (AVM), or an artery wall that breaks open which results in damage to cerebral tissue leading to necrosis. The blood accumulates and compresses the surrounding brain tissue
What symptoms would you get from a:
LACS – Lacunar stroke (deep penetrating arteries) ?
(ONE of the following must be present)
Subcortical stroke - small vessels affected
No loss of higher cerebral function.
One of the following needs to be present for a diagnosis of a LACS:
- Pure sensory stroke
- Pure motor stroke - unilateral weakness of face and arm, arm and leg or all 3
- Senori-motor stroke
- Ataxic hemiparesis
Main motor symptoms that are seen in stroke
Alterations in tone
a. Low tone - flaccidity; relates to lack of stimulation to muscles
b. High tone – spasticity (30-40% post stroke; 5% of these will develop it in the first 10 days post-stroke)
Ataxia - lack of co-ordination (Trunk ataxia, upper limb ataxia, lower limb ataxia or all)
Weakness - relates to how atrophied or hypertrophied a muscle is
Asymmetry
Loss of normal movement patterns - due to asymmetry
Loss of postural adjustments - loss of balance
Compensations - “to counterbalance”
How does a motor pathway create movement?
Descending motor (efferent) signals are sent from the brain to lower motor neurones which innervate muscles to create movement
CVA can damage any descending pathway
Main cognitive symptoms seen in stroke
- Perceptual Problems
a. Agnosia (parietal/ temporal / occipital (memory storage)) - Inability to recognise objects when using a specific sense
i. Astereognosis -inability to identify objects without looking at them (opposite of stereognosis)
ii. Visual Agnosia - cannot recognise objects; relates to ability find the word and function for the object (receptive dysphasia - damage to Wernicke’s area)
iii. Auditory Agnosia - cannot recognise voices of others - can be dangerous, i.e. not recognising a fire/smoke alarm
iv. Olfactory agnosia - inability to recognize odors - can be dangerous, i.e. not smelling a gas leak, fire
b. Depth perception - relates to driving - patients post-stroke will not be allowed to drive for at least 1 month and some will need proper assessment to check on visual perception to ensure they can drive safely. In clinic will be noticed by hitting walls - Apraxia (frontal/ parietal lobes) - difficulty with the motor planning to perform tasks or movements that they understand, i.e. placing tea bag in kettle or incorrect order of getting dresses.
- Anosognosia (not common; right parietal lobe typically) - patient not recognising that have had a stroke
- Inattention/neglect (right parietal lobe)
a. Visual - when they do not recognise affected side of field as they cannot see through it
b. Sensory - when they do not recognise affected side of body as there is no sensation
c. Cognitive - when they do not recognise limbs as their own
d. More common with left hemiplegia
e. Patients fails to attend to stimuli from the left side
f. Poor prognosis if persists
g. Results in many functional problems - self-care, eating, dressing, walking - Behavioural/emotional changes (frontal lobe)
- Organisation/sequencing and memory (temporal lobe)
