Week 3 - D - Stroke - Pathophysiology, treatment, follow up Flashcards
Why does an upper motor neuron lesion lead to hyperreflexia and spasticity of the muscle?
Basically there is the loss of inhibitory descending inputs to the lower motor neuron supplying the muscle so there is increased muscle tone and exaggerated reflexes
Why does a lower motor neuron lesion lead to atrophy and fasciculations?
The muscles twitches as there may be a small number of motor units that are firing but not enough to cause actual contraction
Atrophy will occur due to there being no nerve supply to the muscle
• Stroke is the experience of persisting neurological complications of cardiovascular disease – NOT a diagnosis
What are the symptoms of stroke via the acronym FAST?
F - facial drooping usually occurs unilaterally (or unable to open an eye or even smile)
A - arms, patient may be unable to lift both arms due to weakness in one of the arms
S - Speech may be slurred or unable to speak despite appearing awake
T - tiime to call 999
What are the main types of stroke?
Ichaemic stroke - most common at 85%
Haemorrhagic stroke - 10% of strokes
Subarachnoid haemorrhage - 5% of strokes
What are the different causes of ischaemic stroke?
Cardioembolic, atheroembolic and small vessel disease are the main causes of ischaemic stroke - artery becomes occluded resulting in loss of blood supply to an area of the brain
What is the main cause of haemorrhagic stroke?
What is the condition in which proteins called amyloid build up on the walls
Main cause of haemorrhagic stroke is hypertension
Cerebral amyloid angiopathy is the condition where amyloid deposits are found in the arteries of the brain (this is linked with alzheimer’s dementia but differers from the amyloid depositied in the
What are the three pathological hallmarks of alzhiemers dementia?
Loss of cortical neurons (widening of gyri basically)
Senile plaques - these are amyloid beta protein deposition in the brain parenchyma
Neurofibrillary tangles are aggregates of Tau proteins
Give the difference in definition between a transient ischaemic attack and a stroke?
Stroke is focal neurological deficit lasting longer than 24 hours due to an interruption in blood supply to the brain
The original definition of a transient ischaemic attack (TIA) was time-based: a sudden onset of a focal neurologic symptom and/or sign lasting less than 24 hours, brought on by a transient decrease in blood flow.
However, this has now changed as it is recognised that even short periods of ischaemia can result in pathological changes to the brain. Therefore, a new ‘tissue-based’ definition is now used: a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.
What type of dementia can multiple TIAs be a precursor to?
Due to TIAs actually causing damage to the brain, they can cause vascular dementia
The key to diagnosis of a TIA is via history as the symptoms have usually gone by this time
What is the risk reduction in a stroke happening in a patient who has had a TIA and has been managed early?
80% risk reduction in stroke if a TIA is managed early
If a patient experiences a transient ischaemic attack, what is the scoring system used to determine whether the patient is likely to have a stroke or not and therefore referral should be performed?
This is the ABCD2 scoring system
The maximum score in the ABCD2 scoring system is 7
What are the different categories?
- Age
- Blood pressure
- Clinical features
- Unilateral weakness
- Speech disturbance w/oweakness Duration of symptoms
- Symptoms lasting =/> 1hours
- Symptoms lasting 10-59 minutes Diabetes
Age
Blood pressure
Clinical features
- Unilateral weakness
- Speech disturbance without weakness
Duration of symptoms
Less or greater than an hour
Diabetes
How is each score categorised?
- Age >/= 60
- Blood pressure >/= 140/90
- Clinical features - if unilateral weakness then 2 points, if speech disturbance without weakness then 1 point
- Duration - If symptoms have last >/= 1 hour then 2 points, if 10-59 minutes then 1 point
- Diabetes - 1 point
What score should be referred to a specialist within 24 hours?
When should all patients with a suspected TIA be seen within?
ABCD2 score of >/= 4 should be assessed by a specialist within 24 hours
All patients with a TIA should be seen within 7 days
1/3rd of all stroke presentations are stroke mimics
What are the common causes of stroke mimics?
Seizures, presyncope (light headedness tends to be a global brain dysfunction), space occupying lesion
What is presyncope a common presenting factor of? what is different between presyncope and syncope?
Presyncope is a common presenting factor of orthostatic (postural) hypotension
Presyncope is feeling light headedness and feeling faint whereas syncope is actually fainting
The rosier score is a stroke assessment scale for the likelihood of a stroke
What does the scale score range from and what score is indicative of a stroke?
ROSIER - stands recognition of stroke in emergency room
The scale ranges from -2 to +5
A score of greater than 0 is likely to be a stroke
Less than or equal to 0 decreases likelihood but does not exclude the possibility of stoke
The rosier score asks questions on 7 different points of stroke
Try and name all seven points
Has there been loss of consciousness or syncope
Has there been seizure activity
Is there new acute
- Asymmetrical facial weakness
- Asymmetrical arm weakness
- Asymmetrical leg weakness
- Speech distrubance
- Visual field defects
State what the different scoring is for all 7 points of the rosier scale?
The rosier scale detemrines the likelihood of stroke
Has there been loss of consciousness or syncope = -1
Has there been seizure activty = -1
New acute onset = all are on point
- Unilateral facial weakness
- Unilateral arm weakness
- Unilateral leg weakness
- Speech disturbance - Visual field defect
A score of greater than 0 is likely to be a stroke
Less than or equal to 0 decreases likelihood but does not exclude the possibility of stoke
What is the tool used by healthcare providers to objectively quantify the impairment caused by a stroke?
This is the NIHSS scoring system - national institue health stroke scale - this scale helps with prognosis
State the different categories of the NIHSS system?
0 - no stroke symptoms
1-4 - minor stroke
5-15 - moderate stroke
16-20 - moderate to severe stroke
21-42 - severe stroke
What is the first line investigation if a stroke occurs?
What is the most sensitive investigation for acute infarct and why is this not first line?
First line investigation is CT scan
Diffusion-weighted MRI is most sensitive for acute infarct but CT scan helps to rule out a primary heamorrhage and is therefore first line investigation (in hyperacute, plain CT setting may be normal)
When will a CT show an infarct?
What does this mean for thrombolysis if you see an infarct on CT?
A CT usually takes more than 4/5 hours to show an infarct from the onset of symptoms
Therefore it used to rule out a primary haemorrhage and normally a CT in the acute phase ( 4.5 hrs and thrombolysis shouldnt be carried out
What is the scoring system that allows the size of the stroke to be classified known as?
This is the oxford stroke classification
What are the four different parameters in the Oxford stroke classification?
PACS - Partial Anterior circulation stroke
TACS - Total Anterior Circulation Stroke
POCS - Posterior Circulation Stroke
LACS - Lacunar stroke
What is needed for the diagnosis of PACS?
PACS - Partial Anterior circulation stroke
Any 2 of the following 3:
Unilateral weakness (and/or) sensory defecit in arms/legs/face
Homonmymous hemianopia
Higher cerebral dysfunction - eg dysphasia or visuospatial disorder
What is dysphasia and what is visuospatial disorder?
What is needed for the diagnosis of a TACS (state what it stands for)?
Dysphasia is a language disorder marked by impairment in speech production or comprehension
Visuospatial disorder is where the person would have a loss of awareness
TACS - total anterior circulation sydnrome.,
All three of the following-
Unilateral weakness (and/or) sensory defecit, arms, leg, face
Homonmyous hemianopia
Higher cerebral dysfunction - dysphasia, visuospatial disorder
WHich arteries are affected in a TACS and in a PACS?
In total anterior circulation stroke, it would both the middle and anterior cerebral arteries that are affected
Partial anterior circulation involves the small arteries coming from, usually the middle cerebral artery
Which arteries are affected in posterior circulation stroke?
What is the diagnosing criteria for a POCS?
The vertebrobasilar arteries are affected here (this includes their branches ie the cerebellar arteries)
One of
1. Cerebellar or brainstem syndrome
- Loss of consciousness
- Isolated homonymous hemianopia
LACS - lacunar strokes involves perforating arteries around the internal capsule, thalamus and basal ganglia
WHat are these arteries collectively known as?
These are the lenticulostriate arteries - branches of the middle cerebral artery
What are the diagnostic oxford criteria of a LACS?
Patient presents with 1 of the follwing Unilateral weakness (and/or sensory deficit) of leg, arm or face
Pure sensory loss
Ataxic hemiparases (paresis means weakness) - weakness in the limbs with ataxia also (extension in upper limb, flexion in lower)
Patient presents with isolated homonymous hemianopia, what type of stroke would this be?
Which arteries?
Patient presents with homonymous hemianopia, unilateral weakness of arm and inability to produce speech, what type of stroke would this be?
Which arteries?
Isolated homonymous haemianopia - this would come under the posterior circulation stroke
Vertebrobasilar arteries affected
Homonymous hemianopia, unilateral weakness of arm, inability to produce speech - total anterior circulation stroke - middle and anterior cerebral arteries affected
Patient presents with pure sensory stroke, what type of stroke and which arteries?
Patient presents with homonymous haemianopia and a loss of there awareness in space, what type of stroke and which arteies?
PAtient presents with lcoked in syndorme, what type of stroke could cause this and which arteries?
Pure sensory stroke - lacunar stroke (LACS) - lenticulostriate arteries (small vessel penetrating arteries from middle cerebral artery)
Homonymous haemianopia and loss of awareness in space (visuo-spatial defect) - partial anterior circulation stroke (PACS) - branches of the middle cerebral artery
Locked in syndrome - also known as ventral potine syndrome - brainstem affected meaning - POCS (posterior circulation stroke) - Vertebrobasilar arteries affected
In most people left side of the brain is the dominant side of the brain , therefore left side strokes tend to have a greater functional impact as it is the more dominant hemisphere
Important know the laterality of stroke
What is the least common type of oxford classification of stroke?
Total anterior circulation stroke is the least common type
PACS, POCS, LACS are all equally common
What is the most common cause of ischaemic stroke accounting for 40% of the overall stroke cases?
This would be atheroembolic stroke
In atheroembolic stroke, diseased carotids causes a thrombus to break off and travel to a cerebral artery causing a stroke
Is atheroembolic stroke firbin or platelet dependent?
Atheroembolic infarct is platelet dependent and is generally described as a white thrombus
Most common reason people get cots forming in the heart for cardioembolic origin of stroke is due to what?
How much does this cause of cardioembolic strokes increase the overall risk of stroke occurence by?
Atrial fibrillation
5 fold increase in risk of stroke
What is the scoring system used to calculate the risk of stroke in people with atrial fibrillation? (state what the individual sections are)
CHA2DS2VASc score (Chadsvasc)
CHF
Hypertension
Age >/- 75 = 2points
Diabetes
Stroke/TIA previous = 2 points
Vascular disease
Age 65 - 74
Sex category (female) - max score is 9
What are two causes of haemorrhagic stroke again?
Hypertension - main cause
Cerebral amyloid angiopathy - amyloid deposits in blood vessels make bleeds more likley (also increase risk of Alzhiemer’s disease)
What are some pointers to haemorrhagic stroke? (ie symptoms)
If an ECG is negative for atrial fibrillation, what is carried out for next investgation?
Meningism - stiff neck, headache, photophobia
Headache leading to coma
If ECG negative for Afib, carry out a 72 hour ECG tape
Need to CT scan first to rule out haemorrhage because if they have a haemorrhage then not going to thrombolyse or give aspirin
If CT is potivie for infarct, thrombolysis is given if within what time limit?
What is given if over this time limit?
If within 4.5 hours then thrombolyse the patient
If over 4.5 hours give patient IV aspirin and supportive care
If thrombolysis is given, how long must be waited before giving aspirin to the patient?
What investigation must be carried out before giving the aspirin?
24 hour post thrombolysis CT scan must be carried out to show an absence of intracranial haemorrhage before giving aspirin (need to wait at least 24 hours post thrombolysis)
If the cause of the stroke is found to be atheroembolic (due to a carotid scan), what is given?
If the cause of the stroke is found to be cardioembolic (ECG) , what is given?
Atheroembolic
Aspirin (300mg) for 14days post stroke and then
1st line - clopidogrel 75mg indefinitely , 2nd line - Aspirin + dipyridamole
Cardioembolic
Aspirin for 14 days then life long anticoagulant therapy (warfarin usually drug of choice or NOACs)
Anticoagulants are not routinely recommended in the long-term prevention of recurrent stroke, except in patients with atrial fibrillation.
Irrespective of the patients cholesterol level, how quicly should a statin be started?
if the cholesterol is > 3.5 mmol/l patients should be commenced on a statin. Many physicians will delay treatment until after at least 48 hours due to the risk of haemorrhagic transformation
What treatment is given to reduce the risk of DVT post stroke in patients?
Intermittent pneumatic compression
So for full diagnosis – need laterality, type and size of stroke (eg left cerebral, cardioembolic POCI)
WHat is the diagnosis of POCI? WHich arteries are affected?
55 year old male presents with sudden onset of weakness in left side of his arms and face, with dysphasia. he is known to have carotid steonsos
Give the full diagnosis of the stroke?
POCI - the vertebrobasilar arteries are affected - ONE OF
- Loss of consciousness
- Cranial nerve or brainstem features
- Isolated homonymous hemianopia55 year old male answer -
- Right cerebral, atheroembolic PACI
- Most likely to be a PACI - two of the following
- Unilateral weakness (and/or) sensory deficit in face, arms legs - Homonymous hemianopia, higher cerebral dysfuncton
What symptoms may arise if a patient has a stroke affecting the
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
Anterior cerebral - Contralateral hemiparesis and sensory loss, lower extremity > upper
Middle cerebral - Contralateral hemiparesis and sensory loss, upper extremity > lower
Contralateral homonymous hemianopia
Aphasia
Posterior cerebral artery - Contralateral homonymous hemianopia with macular sparing
Visual agnosia
