Stroke presentation & investigation Flashcards
Why is prevention of stroke important to the NHS?
Commonest cause of long term disability in the UK
Patients who’ve had a stroke occupy 20% of NHS beds
Annual cost of over £5 billion treating stroke
What age demographic has the most strokes?
The elderly
Define what a stroke is
Clinical syndrome of sudden onset, causing a neurological deficit (loss of function)
Lasting more than 24 hours or until death
Of Vascular origin
Symptoms of a stroke are defined as being negative symptoms
What does this mean?
Symptoms are more to do with ‘loss of _______’
Symptoms of stroke: Loss of power Loss of speech Loss of sensation Loss of vision Loss of coordination
Describe the clinical signs, on history/examination, that would indicate a stroke
Motor - clumsy/weak
Sensory loss
Speech - Dysarthria/dysphasia
Neglect / visuospatial problems
Vision - loss in one eye or hemianopia
Gaze palsy
Ataxia / vertigo / nystagmus
What is hemianopia?
Blindness over half the field of vision
What is gaze palsy?
Inability to move both eyes in the same direction
What is ataxia?
lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements
What is nystagmus?
Dancing eyes
Rapid fluttery eye movements
What are the 2 types of causes of strokes?
Cerebral infarction
Haemorrhage
What are the 2 artery groups that supply the brain
Vertebral arteries (L & R)
Common carotid arteries (L & R)
What does the common carotid arteries split into?
Internal & external carotid arteries
What is the fate of the vertebral arteries?
Left and right vertebral arteries join together to form the single Basilar artery
What arteries branch off the Basilar artery?
Posterior inferior cerebellar arteries
Superior cerebellar arteries
Posterior cerebral arteries
What arteries make up the circle of willis?
Anterior communicating artery top
Anterior cerebral arteries
Internal carotid arteries/middle cerebral arteries
Posterior communicating arteries
Posterior cerebral arteries bottom
Most cerebral infarctions involve thrombus lodging in what arteries?
Middle cerebral arteries
The brain’s arterial supply can be thought of as an anterior and posterior circulation
What areas of the brain does the carotid system supply?
Anterior
The carotid system (via internal carotid arteries) supplies most of the hemispheres and cortical deep white matter
What areas of the brain does the vertebral artery system supply?
Posterior
Vertebro-basilar system supplies the brainstem, cerebellum and occipital lobes
In the deep white matter of the brain, a small stroke can cause major deficits
Why?
In the deep white matter of the brain or in the pons, neural fibres from different areas of the brain run alongside each other in tight, internal capsules
A small stroke in this area will affect all these fibres thus have affect lots of different areas
What are the causes of a ischaemic stroke (cerebral infarction)?
Large artery atherosclerosis:
- Typically in the carotid
Cardioembolic:
- Atrial fibrillation most common cause of this
Small artery occlusion - Lacunar
Less common:
- Cryptogenic
- Arterial dissection
- Venous sinus thrombosis
What are the causes of a hemorrhagic stroke?
Primary intracerebral haemorrhage:
- Blood vessel bursting within the brain
- Most common (70% HS’s)
Subarachnoid haemorrhage:
- Blood in the space around the brain
Arteriovenous malformation:
- Poorly formed blood vessels that ‘leak’
What does a hemorrhagic stroke look like on a CT?
Darker grey area
Will extend to the peripheries if subarachnoid haemorrhage
What is a lacunar stroke?
Happens when the small arteries to lacunae (gaps in the brain) are blocked
On a CT, it is a hard to see, slightly darker patch
On an MRI, it is a slightly lighter patch
What is a carotid dissection?
When the intimal layer of a carotid artery separates from the media
Blood clot fills in the space
Can be idiopathic or caused by trauma
It is a rarer cause of cerebral infarction strokes (ischaemic stroke)
A patient presents with a stroke
They have homonymous hemianopia
What is this, and what is likely to have caused it?
They have lost half of the field of view in each eye
Sight lost from the same side on both eyes
A stroke in the left occipital cortex would cause the patient to lose the right half of the field of view of both the eyes
Clinically, strokes are classed into 4 subtypes according to the Oxford clinical stroke classification
What are these?
TACS - total anterior circulation stroke
PACS - partial anterior circulation stroke
LACS - lacunar stroke
- pure motor / pure sensory / sensorimotor
POCS - posterior circulation stroke
A patient presents with:
- Weakness
- Sensory deficit
- Homonymous hemianopia
- Dysphasia (slurring)
- Dyspraxia
What type of stroke do they have?
TACS
A patient presents with:
- Weakness of their left arm
- Weakness of their left side of their face
What type of stroke do they have?
Pure motor LACS
“Complete or incomplete weakness in 1 side of the body in 2 of either the face, arm or leg”
A patient presents with:
- Dysphasia
- Dyspraxia
What type of stroke is the patient having?
PACS (partial anterior)
2/3 of TACS criteria, basically the patient will have some signs of TACS but will be fine in other ways
Ie - Weakness in limbs/face but still able to talk normally
A patient presents with:
- Bilateral motor/sensory deficit
- Disordered breathing
- Tinnitus
- Isolated homonymous hemianopia
What type of stroke are they having?
POCS (posterior)
POCS present with variable, unique symptoms
Stuff like tinnitus, Horner’s, coma, = POCS
A patient presents with:
- Loss of feeling in the right arm and right leg
What type of stroke are they having?
Pure sensory LACS
What is the most common subtype of stroke?
PACS (partial anterior) - 35%
TACS are usually caused by occlusion of what vessels ?
Proximal middle cerebral artery
or
Internal carotid
What causes PACS to happen?
More restricted cortical infarcts - occlusion of branches of middle cerebral artery
What areas of the brain are affected by POCS?
Brainstem, Cerebellum or Occipital lobes
Which is the most dangerous type of stroke?
TACS
60% mortality at 1 year
What is the one year prognosis for someone who survives a TACS?
Lowest recurrence of all subtypes at only 6% @ 1 year
What is the mortality and recurrence rate for PACS?
16% mortality in 1 year
17% recurrence rate in 1 year
high chance of recurrence in early stages
What is the mortality and recurrence rate for LACS?
11% mortality at 1 year
9% recurrence at 1 year
What is the mortality and recurrence rate for POCS?
19% mortality at 1 year
20% recurrence at 1 year (highest)
What are the risk factors for stroke?
Age Race (chinese most at risk) Family history Hypertension Atrial fibrillation
Also: Smoking & alcohol Diet & Exercise Stress & Depression Diabetes Hyperlipidaemia & all that shite
Why is atrial fibrillation a risk factor for stroke?
Atrial fibrillation can cause a cardioembolic ischaemic stroke
Which gender is most at risk of a stroke?
In adult to early old age (<75) - men are more at risk
In > 75 age group, women are more at risk
