Cerebral infarction (CLINICAL) Flashcards
at what age do the majority of strokes occur
~75% in >65 yr olds
define stroke
the sudden onset of focal or global neurological symptoms caused by ischemia or hemorrhage and lasting more than 24 hours
define transient ischaemic attack (TIA)
the term used if the symptoms resolve within 24 hours
most resolve within 1-60 mins
what is more common - ischaemic or haemorrhagic stroke
ischaemic - 85%
what are the most common causes of ischaemic stroke
- Large artery atherosclerosis (e.g. Carotid - 35%
- Cardioembolic (e.g. atrial fibrillation) - 25%
- Small artery occlusion (Lacune) - 25%
- Undetermined/Cryptogenic 10-15%
- Rare causes - <5%
- Arterial dissection
- Venous sinus thrombosis
what are the causes of haemorrhagic stroke
- Primary intracerebral haemorrhage - 70%
- Secondary haemorrhage - 30%
- Subarachnoid hemorrhage
- Arteriovenous malformation
what are the investigations for stroke
blood tests - FBC, glucose, lipids, ESR
CT or MRI head - infarct vs haemorrhage
ECG - ?AF, LVH
Echocardiogram - valves, ASD, VSD, PFO
carotid doppler US - ?stenosis
Cerebral angiogram/venogram - ?vasculitis
hyper-coagulable blood scan
what can conditions can present like stroke but are not stroke
Post-ictal states (e.g. Todd’s paralysis)
Hypoglycemia
Intracranial masses
Vestibular disease
Bell’s palsy
Functional hemiparesis
Migraine
Demented patients with UTIs
what is the incidence and impact of stroke
2nd, 3rd cause of death in developed countries
number 1 cause of disability in adults
150,000 new stroked/year in the UK
what is the public awareness campaign for stroke
act FAST
F- facial weakness
A - arm weakness
S - speech problems
T - time to call 999
what are the 4 basic steps in the pathophysiology of stroke
- ischaemia develops
- results in hypoxia
- leads to anoxia
- leads to infarction
explain the ischaemic stage of stroke pathophysiology
ischaemia:
- failure of the cerebral blood flow to a part of the brain
- caused by an interruption of the blood supply to the brain
- can be transient (as in TIA)
- results in varying degrees of hypoxia (decreased oxygen)
explain the hypoxic stage of stroke pathophysiology
hypoxia:
- stresses the brain cell metabolism (especially important in the ischameic penumbra)
- if prolonged hypoxia - leads to anoxia (no oxygen)
explain the anoxic and infarction stages of stroke pathophysiology
anoxia:
- leas to infarction
infarction:
- complete cell death leading to necrosis
- this is a stroke
what can further damage result from in stroke
edema - depending on size and location of stroke
secondary haemorrhage into the stroke
what is the penumbra
the area surrounding an ischemic event such as thrombotic or embolic stroke - oxygen supply to this area is also disrupted - leads to hypoxia in the surrounding area
how can total arterial occlusion develop in ischaemic stroke
- disruption/injury to a plaque surface
- platelet adhesion/aggregation and fibrin formation on plaque
- thrombus formation
- leads to total arterial occlusion due to thrombus
if parts of the thrombus break off and block further areas = embolus
what are the two groups of risk factors for stoke and give examples of each
modifiable
- hypertension
- smoking
- cholesterol
- diet
- high BMI
- alcohol
non-modifiable
- previous stroke
- age
- male
- family history
diabetes
what is the most important modifiable risk factor for stroke and why
HYPERTENSION
- stroke related to blood pressure level
- chronic worsens atheroma and affect small distal arteries
- reach elderly populations
- majority poorly treated
**major risk factor for haemorrhagic stroke as well
how can increased serum lipids, hypertension, smoking and diabetes increase the risk of stroke
all contribute to LDL-C deposition in arterial walls
increased plasma level LDL = excessive amounts of LDL in the arterial walls
= blood vessel wall atheroma
what are three other risk factors for stroke not already mentioned
impaired cardiac function
- recent MI, AF
OCP (+HRT)
- high oestrogen bad
- progesterone only ok
hyper-coagulable states
- malignancy
- gentic
what is the anterior blood supply to the brain
2 x Internal carotid arteries
2 x Anterior Cerebral Artery (ACA)
2 x Middle Cerebral Artery (MCA)
2 x Posterior Communicating Artery (PComA)
what is the posterior circulation to the brain
2 Vertebral arteries →1 basilar
3 pairs of cerebellar arteries (ant/post inferior, superior)
2 Posterior cerebral artery (PCA)
what do the anterior and posterior circulation join to form
the circle of willis
what are symptoms of ACA occlusion
CONTRA-LATERAL
- paralysis of foot and leg
- sensory loss over foot and leg
- impairment of gate and stance
what are the symptoms of MCA occlusion
CONTRA=LATERAL
- paralysis of face/arm/leg
- sensory loss face/arm/leg
- homonymous hemianopia
gaze deviation to same side from paralysis to the opposite side
e.g. left MCA occlusion
= gaze deviation to left BUT muscles on right paralysed
what other symptoms would be seen if there was MCA occlusion on the dominant side
if stroke on dominant side (usually left) =
dys/aphasia (difficulty with language or speech)
what other symptoms would be seen if there was MCA occlusion on the non- dominant side
if stroke on non-dominant side (usually right) =
unilateral neglect
visual and sensory agnosia (inability to recognise things) for half of external space
anosagnosia - denial of hemiplegia
prosopagnosia - failure to recognise faces
what is the arterial supply of the basal ganglia
the small penetrating (lacunar) arteries of the MCA
what does loss of circulation to the basal ganglia cause
lacunar ischaemic stroke
what are lacunar stroke syndromes
devoid of “cortical” signs
- eg no dysphasia, neglect, hemianopia
- pure motor stroke
- pure sensory stroke
- dysarthria - clumsy hand syndrome
- ataxic hemiparesis
what structures are involved in posterior circulation symptoms
brainstem cerebellum thalamus occipital lobe medial temporal lobe
what are the symptoms of brainstem dysfunction
Coma, vertigo, nausea, vomiting, cranial nerve palsies, ataxia
Hemiparesis, hemisensory loss
Crossed sensori-motor deficits
Visual field deficits
what should the treatment for acute ischaemic stroke aim to do
restore blood supply
prevent extension of ischaemic damage
protect vulnerable brain tissue
what are the first line treatments for stroke
Aspirin
Heparin
Neuroprotectant
Tissue Plasminogen Activator (TPA) - thrombolysis
Intra-arterial therapy - thrombectomy
what additional support can improve good outcome of stroke
stroke units
who makes up a stroke unit
Clinical staff Stroke nurses Physiotherapists Speech and Language therapists Occupational therapists Dietitian Psychologist Orthoptist
what are the 4 main types of stroke
TACS - total anterior circulation stroke
PACS - partial anterior circulation stroke
LACS - lacunar stroke
POCS - posterior circulation stroke
how would you identify LACS
pure motor >2/3
pure sensory >2/3
how would you identify PACS
pure motor >2/3
pure sensory >2/3
1 of hemaniopia, dysphasia, neglect
how would you identify TACS
pure motor >2/3
pure sensory >2/3
MUST HAVE HEMIANOPIA
+ dysphasia or neglect
how would you identify POCS
all other symptoms
BRAINSTEM and or CEREBELLAR SIGNS
of the 4 strokes, which has the highest death or dependency level at 6 months
TACS - 96%
what is the criteria for tissue plasminogen activator (TPA) use
<4.5 hours from symptom onset
disabling neurological deficit
symptoms present >60 mins
CONSENT
what is the exclusion criteria for IV TPA
anything that increases the possibility of haemorrhage
- blod on CT
- recent surgery
- recurrent bleeding
- coagulation problems
BP >185/>110
glucose <2.8 or >22mmolL
what happens to the benefit of TPA as time passes
decreases - if started too late can actually cause harm
what are the two types of thrombectomy
MERCI-corkscrew
solitaire thrombectomy
why are TIAs like angina
warning sign
as angina is to MI - TIAs are to stroke
what is the recurrence rate of stroke with TIA
10% stroke recurrence rate in the first 2 weeks after TIA
what treatment is effective in symptomatic internal carotid artery stenosis
carotid endarterectomy
after initial treatment, what should the follow management of stroke include
Prevention of stroke recurrence.
Prevention of complications related to stroke.
Rehabilitation.
Re-integration into the community
what are some preventative second line treatments for stroke
- anti-hypertensives
- anti-plateletes
- lipid lowering agents
- warfarin for AF
- carotid endarterectomy
what are the overall objective of stroke care
Reduce mortality.
Reduce residual disability amongst survivors.
Improve psychological status of patients and care-givers.
Improve patient / care giver knowledge.
Maximize quality of life
