Module 2D - Stroke Flashcards
2 causes of ischaemic strokes
thrombotic or embolic
Types of haemorrhagic stroke + aetiology
- Extradural –> bleeding between skull and dura mater
- Subdural –> bleeding between dura mater and arachnoid mater
- Intracerebral –> bleeding into brain tissue
- Subarachnoid –> bleeding in the subarachnoid space
Oxford classification of stroke (Bamford classification)
Risk factors for a stroke
- Main –> smoking, AF, hx of previous stroke or TIA
- Other –> hypertension, hypercholesterolemia, obesity, family hx, vasculitis, combined oral-contraceptive pill
(stroke is associated with co-morbidities such as cardiovascular disease and vascular disease –> share the same risk factors)
Definition of stroke, TIA, crescendo TIAs
- Stroke = a clinical syndrome characterised by rapidly developing clinical symptoms and/or signs of focal neurological deficit lasting more than 24hrs and thought to be of vascular origin
- TIA = neurological signs/symptoms that are consistent with a stroke that resolve within 24hrs
- Crescendo TIAs = two or more TIAs within a week and indicate a high risk of stroke
Common symptoms of a stroke
- One-sided muscle weakness (hemiparesis)
- Dysphasia (speech disturbance)
- Aphasia (expressive/receptive/global)
- One-half visual field defects (hemianopia) - often lose one-half of visual field in each eye which results in neglect on one side of the body
- Sensory loss
- Ataxia and vertigo
Stroke findings on examination (tone, power, sensation, reflexes, coordination, visual fields, facial nerve)
- Tone –> low/normal early in stroke, but increases with time (clasp knife spasticity/reflex)
- Power –> reduced power on affected side, pronator drift
- Sensation – > can be reduced (affects limbs rather than dermatomes), pt may have signs of neglect on affected side (tactile agnosia/astereognosis = inability to recognise objects by touch alone)
- Reflexes –> should be normal in a stroke patient
- Coordination –> can be affected
- Visual fields –> usually have hemianopia
- Facial nerve (7th cranial nerve) –> usually facial droop (spares eyebrows, complete paralysis is Bell’s Palsy)
Does stroke always affect the contralateral side of the body?
Not always –> if cerebellum affected then ipsilateral presentation
Is stroke an UMN or LMN?
UMN
Label the cerebral arteries.
- Which arteries supply anterior brain
- Which arteries supply posterior brain
- Blood is delivered to brain through 4 main arteries, two internal carotid arteries (anterior supply), and two vertebral arteries (posterior supply to the brain)
- Anterior supplied by internal carotid arteries which form the ACA and MCA
- Anterior connects with Posterior via posterior communicating artery
- Posterior supplied by vertebral arteries which combine to form the Basilar artery
(The brain also has a venous drainage system which drain into the venous sinuses)
Which arteries form the Circle of Willis?
- What is function of Circle of Willis?
- Formed by basilar artery, internal carotid artery, and middle cerebral artery
- Safeguards the oxygen supply from interruption by arterial blockage
- For example, if there is stenosis in one artery then other source arteries to the Circle of Willis can provide an alternative blood flow (collateral circulation)
The limbic system is made up of the hippocampus and amygdala, what are their functions?
Limbic system is involved in behavioural and emotional responses (survival, fight or flight)
- Hippocampus –> memory centre, spatial orientation, neurogenesis occurs here (key brain structure for learning new things)
- Amygdala –> central role in emotional responses (pleasure, pain, fear, anxiety, anger), attaches emotional content to memories
Functions of frontal lobe, parietal lobe, temporal lobe, and occipital lobe
- Frontal lobe –> higher executive function (emotions, planning, reasoning, problem-solving), primary motor cortex (responsible for voluntary movement)
- Parietal lobe –> sensory info (touch, temp., pressure, pain), two-point discrimination can be used to assess
- Temporal lobe –> sensory info (hearing, recognising language, forming memories), primary auditory cortex (can understand what we hear), making sense of complex visual info (faces and scenes), hippocampus (memory, learning, emotions)
- Occipital lobe –> Primary visual cortex (major visual processing centre in the brain)
MCA infarct:
- locations affected?
- symptoms associated
- Locations affected –> frontal, parietal, and temporal lobes
Symptoms:
- hemiparesis –> arm worse than leg
- Sensory loss
- Facial weakness –> facial droop/dysarthria
- Dysphasia –> expressive, receptive, global
- Hemianopia –> without macula sparing
Broca’s aphasia vs Wernicke’s aphasia
- Broca’s –> expressive dysphasia (pt can understand what is said but cannot express with words, difficult to speak)
- Wernicke’s –> receptive dysphasia (pt doesn’t understand what is being said, but can still talk normally, but it doesn’t make any sense)
If a right-hand dominant patient has Broca’s or Wernicke’s aphasia then which side is the stroke?
- Left MCA
- Broca’s and Wernicke’s area are found in the dominant cerebral hemisphere
- left side for right-handed
- right side for left-handed
ACA infarct:
- locations affected?
- symptoms associated
- Locations affected –> frontal and parietal lobes
Symptoms:
- hemiparesis –> leg worse than arm
- Apathy –> lack of interest, enthusiasm, or concern
- incontinence
- Disinhibition –> lack of restraint in social scenarios (affects motor, emotional, cognitive, instinctual, and perceptual behaviours)
- Mutism
Lacunar stroke:
- locations affected?
- symptoms associated
Locations affected –> Lenticulostriate arteries (small penetrating arteries that supply deep structures
(susceptible to injury secondary to uncontrolled hypertension)
Symptoms:
- Pure motor –> hemiparesis or hemiplegia, dysrthria, dysphagia
- Pure sensory –> numbness/tingling/pain on one side of body
- Sensorimotor –> hemiparesis or hemiplegia with contralateral sensory impairment
What are the watershed zones?
- Symptoms for each
Watershed zones are prone to infarction as they receive blood supply from two arteries
PCA infarct:
- locations affected?
- symptoms associated
Locations affected –> mainly occipital, parts of temporal
Symptoms:
- Hemianopia –> with macular sparing
- Amnesia
- Sensory loss (thalamus)
- Thalamic pain
Where does basilar artery supply and if basilar artery is affected in a stroke, what is the serious condition that can result? + what structure is damaged to cause this
- Supplies lower midbrain, pons, and medulla (and occipital lobe)
- Infarction causes locked-in syndrome –> individual has full consciousness but is paralysed
- due to damage to corticospinal tracts (quadriplegia)
- Respiratory muscles also paralysed so individual has to be ventilated –> resp. failure and coma/death can be result
Grey and white matter
- Grey matter –> neuronal cell bodies (business end)
- White matter –> myelinated axons (wiring)
Note: stroke doesn’t differentiate between grey and white matter – can affect both
Acute stroke management
- Non-contrast CT is mainstay investigation
- Thrombectomy –> Can be done together with IV thrombolysis if within 4.5hrs onset –> CT perfusion or CT angiography used to assess salvageable brain tissue
Contraindications for thrombolysis
- pt on DOAC or Warfarin (check INR)
- Hx of surgery, Hx of bleeding (external/internal)
- Uncontrolled hypertension –> BP > 180/120mmHg
What investigation should be done 24hrs after onset of a stroke
Repeat CT head to check for haemorrhagic transformation
Longer-term management of ischaemic stroke
- Aspirin 300mg daily –> for 2 weeks (start aspirin 24hrs after thrombolysis and once repeat CT confirms no haemorrhage)
- After the 2 weeks –> Clopidogrel 75mg –> lifelong
- Atorvastatin 20-80mg (after 48hrs) –> lifelong
- Address modifiable risk factors –> smoking, diabetes control, AF control (if ECG showed AF to be the cause), exercise
Indications for carotid endarterectomy
- If carotid artery doppler ultrasound confirms > 50% carotid stenosis
- (risk of clot embolising and causing stroke)
ROSIER score
(recognition of stroke in the emergency room)
Exclude hypoglycaemia first then assess the following:
- a stroke is likely if > 0
FAST tool for stroke
simple way to identify stroke in the community
F – Face
A – Arm
S – Speech
T – Time to call 999
NIH stroke scale (NIHSS) + criteria for no stroke/mod stroke/mod-sev/severe
NIH Stroke Scale (NIHSS) used as an initial assessment of the patient for suspected stroke and gives a rough idea of how severe the stroke is
(used in secondary care)
- < 5 –> no stroke/minor
- 5-15 –> moderate
- 16-20 –> moderate-severe
- 21-42 –> severe
Vascular territories
Intracranial bleed –> blood is bright
Extradural haemorrhage –> lens/lemon shaped
Subarachnoid haemorrhage
- Rare cause of stroke, usually secondary to trauma, can be idiopathic or due to a ruptured aneurysm
Thalamic haemorrhage
Acute onset R side weakness, 60yrs female
MCA infarct (left)
MCA infarct (right)
ACA infarct
Lacunar infarction
R homonymous hemianopia 80yr male
Acute left PCA infarct –> loss of grey-white matter differentiation
Dense MCA sign –> visible immediately, shows the responsible arterial clot
Right MCA infarct with midline shift
Which side is normal?
- Haemorrhagic stroke
- Previous ischaemic stroke can become haemorrhagic and ciprofloxacin is a P450 inhibitor which increases the effects of warfarin, her blood is very thin!
CT angiography + what sign on a CT would indicate a CT angio…
Catheter angiography
Stroke mimics
- Tumour
- Epilepsy and Todd’s palsy - can cause people to have right/left-sided weakness
- Multiple sclerosis
- Bells palsy (LMN lesion) - paralysis/weakness of one half of the face
- Hypoglycaemia / other metabolic disorder
- Hypothermia
- Sepsis
- Old strokes who are unwell
- Dementia
Warfarin reversal agents
Vitamin K and prothrombin complex concentrate
Heparin/LMWH reversal
Protamine sulfate
Dabigatran reversal agent
Idarucizunab
Apixaban, edoxaban, and rivaroxaban reversal agent
Andexanet alfa
MOA of DOACs
- Apixaban, edoxaban, and rivaroxaban directly inhibit activated factor X (Xa) –> preventing conversion of prothrombin to thrombin
- Dabigatran directly inhibits thrombin –> preventing conversion of fibrinogen to fibrin
(all DOACs therefore inhibit fibrin formation)
Contraindications for DOACs
- Active bleeding/risk factors for bleeding
- Pregnancy and breastfeeding
MOA of Warfarin
- Production of clotting factors II, VII, IX, and X (vit K-dependent) require vitamin K in its reduced form to act as a cofactor
- Warfarin inhibits vitamin K epoxide reductase which prevents formation of reduced vitamin K
For patient’s on anticoagulant therapy, what is the INR target range? + what value indicates a risk of bleeding?
- 2.0-3.0
- > 4.9 is high risk of bleeding
MOA of heparin and fondaparinux
Enhances anticoagulant effects of antithrombin –> inactivates clotting factors
Complications of stroke (hospital problems)
- dysphagia/aspiration pneumonia –> most common cause of death pst-stroke in hospital setting –> SLT assessment + fluids
- DVT/PE –> normal pt (antiplatelets), stroke pt (mechanical stockings –> we don’t want to turn an ischaemic stroke into a haemorrhagic stroke)
- UTI –> stroke can cause bowel/bladder issues
- spasticity
- shoulder subluxation
- depression
- nutrition
- pressure sores –> look for bruising on pressure areas of body
Visual fields
How would you manage a patient who has had an ischaemic stroke and they have atrial fibrillation?
Anticoagulants should not be started until brain imaging has excluded haemorrhage, and not until 14 days after the onset of an ischaemic stroke
Cerebrovascular accident video
Dr Matt and Dr Mike video:
https://www.youtube.com/watch?v=Mx0kMD6Dewo&t=325s
Cerebellar stroke symptoms
- Problems with moving/walking –> balance (cerebellum is part of brain responsible for balance)
- Vertigo –> ‘room spinning’
- muscle weakness or tremors
- headache
- nausea and vomiting
- hearing and vision problems
Management of crescendo TIAs
Aspirin 300mg and review in TIA clinic within 24hrs
Stroke/TIA –> DVLA guidelines for car drivers
- Must stop driving immediately
- Must stop for 1 month
- Must inform DVLA if after 1 month you still have –> weakness in arms or legs, eyesight problems (visual filed loss or double vision), or problems with balance, memory, or understanding –> or if doctor says not safe to drive
Stroke/TIA –> DVLA guidelines for bus/lorry drivers
- stop driving immediately
- Must stop driving for at least one year, can only restart when doctor says it is safe
Patients with a thrombus in which location area most likely to benefit from thrombectomy?
Proximal MCA
Most common cause of a lacunar stroke
Long-standing hypertension
Homonymous hemianopia in PCA vs MCA
- PCA –> macular sparing due to occipital dual blood supply
- MCA –> without macular sparing
A 72-year-old man with atrial fibrillation on warfarin therapy presents to the outpatient clinic with an International Normalized Ratio (INR) of 6.0. He has no history of bleeding or current signs of bleeding.
What is the most appropriate management for this patient?
Hold warfarin for a few days
–> INR 5-8 and no active bleeding, the appropriate management is to withhold warfarin
–> INR above 8 would indicate oral vitamin K to be given
