Stroke Flashcards
What is a stroke?
Damage or death of brain cells
Due to ischaemic hypoxia of those brain cells
What is a transient ischaemic attack TIA?
Stroke that recovered within 24 hours from the onset of symptoms
What is stroke syndrome?
Group of signs and symptoms produced
Due to blockage of an artery supplying part of the brain
What are the types of stroke? Which is the most common?
Ischaemic - most common
Haemorrhagic
Dissection
Venous sinus thrombosis
What causes blockage of arteries supplying the brain? What is the most common cause?
Embolus - most common cause
Vasculitis
Sickle cell anaemia
Cocaine
Where do emboli blocking arteries supplying the brain arise from? Which is the most common source?
Carotid arteries - most common
The heart e.g. atrial fibrillation, valvular disease, prosthetic valves, endocarditis
How does cocaine cause blockage of the arteries supplying the brain?
Causes vasoconstriction of the arteries
What are the signs and symptoms of anterior cerebral artery stroke syndrome?
Sensory symptoms
-loss of all sensory modalities in the contralateral lower limb
Motor symptoms
-initial hypotonia, followed by hypertonia paralysis in contralateral lower limb
Loss of voluntary control over micturition
Split brain syndrome
Alien hand syndrome
Why does anterior cerebral artery stroke syndrome cause loss of voluntary control over micturition?
Damage to cortical centres that voluntarily inhibit micturition reflex
Why does anterior cerebral artery stroke syndrome cause split brain syndrome and alien hand syndrome?
Damage to corpus callosum
The two cerebral hemispheres cannot communicate with each other and are in disagreement with each other
Is a middle cerebral artery stroke syndrome with a proximal or distal blockage more severe?
Proximal blockage
What is an immediate complication of a middle cerebral artery stroke syndrome with a proximal blockage?
Significant amount of damaged and dead brain tissue
Significant cerebral oedema
Raised intracranial pressure
May lead to coma and death
How is raised intracranial pressure with a middle cerebral artery stroke syndrome with a proximal blockage treated?
Decompressive hemicraniectomy
-refers to removing half of the skull to relieve the pressure inside the skull
What do the signs and symptoms of middle cerebral artery stroke syndrome depend on?
How proximal or distal the blockage is
-to the lenticulo-striate arteries
What are the signs and symptoms of middle cerebral artery stroke syndrome with a proximal blockage?
Sensory symptoms
-loss of all sensory modalities in contralateral side of face and upper limb
Motor symptoms
-initial hypotonia, followed by hypertonia paralysis, in whole contralateral side of body
Homonomous hemi-anopia
Global aphasia if dominant hemisphere affected
Neglect if non-dominant hemisphere affected
Why does middle cerebral artery stroke syndrome with a proximal blockage cause paralysis in the whole contralateral side of the body?
Due to lenticulo-striate arteries not supplying internal capsule
So all upper motor neurones are damaged or dead
What are the signs and symptoms of middle cerebral artery stroke syndrome with a distal blockage?
Sensory symptoms
-loss of all sensory modalities in the contralateral side of the face and the upper limb
Motor symptoms
-initial hypotonia, followed by hypertonia paralysis in contralateral side of face and upper limb
Quadrantanopia
If dominant hemisphere affected, Broca’s or Wernicke’s aphasia
If non-dominant hemisphere affected, neglect
Why does middle cerebral artery stroke syndrome cause visual field defects?
Damage to superior and inferior optic radiations in the parietal and temporal lobes
Why does middle cerebral artery stroke syndrome cause aphasia?
Damage to Broca’s and Wernicke’s area
What is neglect?
Patient fails to acknowledge one half of their body and the external environment
That is not due to a lack of sensation, but a lack of processing
What are the signs and symptoms of posterior cerebral artery stroke syndrome?
Homonymous hemianopia
Macular sparing
Why does posterior cerebral artery stroke syndrome cause homonymous hemianopia?
Damage to superior and inferior optic radiations in occipital lobe
What do the signs and symptoms of a cerebellar artery stroke syndrome depend on?
How proximal or distal the blockage is
What are the signs and symptoms of cerebellar artery stroke syndrome with a proximal blockage?
Brainstem symptoms
-crossed deficits
Cerebellum signs
-DANISH
What are crossed deficits?
Ipsilateral symptoms on head and neck due to damage to cranial nerve nuclei
Contralateral symptoms in rest of body due to damage to cerebral peduncles
What are the signs and symptoms of a cerebellar artery stroke syndrome with a distal blockage?
Cerebellum symptoms
-DANISH
What do the signs and symptoms of basilar artery stroke syndrome depend on?
How proximal or distal the blockage is
What are the signs and symptoms of basilar artery stroke syndrome with a proximal blockage?
Locked-in syndrome
What causes locked-in syndrome?
Reduced blood supply to pons
Why structures and functions are lost in locked-in syndrome?
Ventral pons contains corticospinal tract, loss of motor control over the body
Pons and medulla contain cranial nerve nuclei 5-12, loss of function of cranial nerves 5-12
What structures and functions are preserved in locked-in syndrome?
Reticular activating system, hence are conscious
Sensory system, hence are aware of environment
Cranial nerves 1-4, hence can make eye moments
What are the signs and symptoms of basilar artery stroke syndrome with a distal blockage?
Blindness
Loss of sensation
CN3 oculomotor nerve palsy
Why does basilar artery stroke syndrome with a distal blockage give blindness?
Damage and death of both occipital lobes
Why does basilar artery stroke syndrome with a distal blockage give loss of sensation?
Damage and death of both thalami
Why does basilar artery stroke syndrome with a distal blockage give CN3 oculomotor nerve palsy?
Damage and death of midbrain where CN3 nuclei is located
What is a lacunar artery stroke syndrome?
Signs and symptoms due to blockage of the lenticulostriate arteries which supply the internal capsule
What are the signs and symptoms of a lacunar artery stroke syndrome?
Pure motor symptoms
-initial hypotonia, followed by hypertonia paralysis in whole contralateral side of body
What does the thalamoperforator artery branch off?
The posterior cerebral artery
What is a thalamoperforator artery stroke syndrome?
Signs and symptoms due to blockage of the thalamoperforator artery with supplies part of the thalamus
What are the signs and symptoms of thalamoperforator artery stroke syndrome?
Pure sensory symptoms
-loss of all sensory modalities in whole contralateral side of body
What investigations are done for a patient with a stroke?
Blood tests
CT head scan
Why is a CT head scan done for a patient with a stroke?
To distinguish between an ischaemic stroke and a haemorrhagic stroke
What does an ischaemic stroke look like on a CT head scan?
May appear normal
Hyperdense artery i.e. bright artery, due to it containing blood clot
Hypodense grey matter i.e. dark grey matter, due to it being ischaemic
When is hypodense grey matter seen on a CT head scan of a patient with a stroke?
More than an hour after the stroke
What do haemorrhagic strokes look like on a CT head scan?
Bright white areas
How is a patient with a stroke treated?
Within 4.5 hours and no contraindications, thrombolysis
Aspirin after 2 days, continue for 14 days
Statins
