Carotid Disease - Stroke/TIA Flashcards
Neurological deficit attributed to an acute focal injury of the central nervous system by a vascular cause. Including cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage.
Stroke
2 different types of stroke
Ischaemic stroke - 80%
Haemorrhagic stroke - 20%
2 different types of ischaemic stroke
Large vessel occlusion
Small vessel occlusion
2 different types of haemorrhagic stroke
Intracerebral haemorrhage
Subarachnoid haemorrhage
What is ischaemic stroke
A blocked artery to the brain, the damage of which depends on location and time.
What is a transient ischaemic attack?
If the blockage self-resolves within 24 hours.
What is the main role of the parietal lobe?
Processing sensory information and proprioception
What is the main function of the cerebellum?
Muscle co-ordination and balance
What do the middle cerebral arteries supply?
Lateral portions of the frontal, parietal and temporal parts of the brain.
What does the anterior cerebral arteries supply?
Medial portions of the frontal and parietal lobes.
What does the posterior cerebral artery supply?
Occipital lobe and thalamus
What is the function of the circle of willis?
Offers alternative ways for blood to get around obstructions.
How does endothelial cell dysfunction occur?
Something irritates or inflames the tunica intima (inner lining of the artery).
When the tunica intima is damaged what forms?
The damage becomes a site for atherosclerosis, plaque forms obstructing blood flow.
What is a plaque made of?
Build up of fats, cholesterol, proteins, calcium and immune cells.
What is an embolism?
Blood clot breaks off from one location and gets lodged in another.
What causes hyaline atheriosclerosis?
When the blood vessel wall becomes filled with protein.
What does hyaline atheriosclerosis cause?
Hypertension and diabetes due to thickening of the arterial wall and narrowing of the lumen.
What is lacunar stroke?
Stroke involving the deep branches of the middle cerebral artery supplying the basal ganglia. The damaged area of the brain goes on to form cysts that look like lakes.
Shock results in
Reduction in blood flow throughout the body
Shock results in what types of ischaemic stroke?
Watershed infarct
What is the ischaemic core?
The tissue that will likely die at the site of a stroke.
What is the ischaemic penumbra?
The tissue surrounding the ischaemic core that is preserved by collateral circulation. May survive if blood flow is restored quickly.
What does the absence of glucose and oxygen for a cell lead to the build up of?
Na+ and Ca2+
What does a build up of high Na+ levels in a cell cause?
Cytotoxic edema
What is cytotoxic edmea caused by?
Na+ drawing water into the cell making it swell.
What does high levels of Ca2+ in a cell lead to?
Damages lipids in mitochondria and lysosomes causing the cell to release apoptosis inducing factors and degradative enzymes.
What are symptoms often seen with anterior/middle cerebral artery stroke?
Numbness
Sudden muscle weakness
What occurs if a stroke affects broca’s area?
Slurred speech
What occurs if a stroke affects wernicke’s area?
Difficulty understanding speech
What symptom’s are often seen with a posterior cerebral artery stroke.
Problems with vision
FAST
Facial drooping
Arm weakness
Speech difficulties
Time - time to get help
How is the site of stroke located within the brain?
CT Flair MRI Angiography
What are the four causes of ischaemic stroke?
Atherosclerosis Thrombus Embolus Shock (general reduction of blood flow)
Define infarction.
Obstruction of the blood supply to an organ or region of tissue, causing local death of the tissue.
Where do the majority of embolisms that cause large vessel occlusion originate from?
Internal carotid artery
Small vessel occlusion causes what?
Lacunar infarcts affecting deep structures in the brain.
Lacunar infarcts affect where?
Basal ganglia and internal capsule
Large vessel occlusions are usually due to what?
Secondary thromboembolism, from atherosclerotic disease in the internal carotid.
What is an intraparenchymal haemorrhage?
A form of intracerebral haemorrhage where bleeding is confined to brain tissue.
What is an intraventricular haemorrhage?
A form of intracerebral haemorrhage where bleeding extends into the ventricles of the brain.
What does the right cerebrum do?
Controls the movement of muscles on the left side of the body.
What are the three causes of subarachnoid haemorrhage?
- Trauma
- Berry aneurysms
- Arteriovenous malformations
What is hydrocephalus?
Dilation of the ventricles of the brain causing increase in intracranial pressure.
What usually causes intracerebral haemorrhage?
Usually due to hypertension leading to charcot bouchard aneurysms.
What are charcot bouchard aneurysms?
Charcot–Bouchard aneurysms are aneurysms of the brain vasculature which occur in small blood vessels often the lenticulostriate blood vessels supplying the basal ganglia.
Associated with chronic hypertension.
What are the three pathological processes that can lead to intracerebral haemorrhage?
- Charcot bouchard aneurysms
- Cerebral amyloid angiopathy
- Arterio venous malformations
How does cerebral amyloid angiopathy occur?
Occurs due to deposition of amyloid protein in small and medium sized cerebral arteries.
Where do amyloid angiopathies more regularly occur?
Periphery of the brain between where the grey matter boarders white matter.
Where do charcot bouchard aneurysms occur?
Lenticulostriate arteries affecting the basal ganglia.
What is an arteriovenous malformation?
Occurs where an artery drains directly into a vein, causing an abnormal tangling of blood vessels due to pressure. (More prone to bleeding and causing ICH)
Where does subarachnoid haemorrhage occur?
In the subarachnoid space between the pia mater and arachnoid membrane.
What are the two reasons subarachnoid haemorrhage may occur?
Trauma Spontaneous due to the rupture of a berry aneurysm.
Where do berry aneurysms occur?
Berry aneurysms arise at sites of arterial bifurcation.
What is the main risk factor for berry aneurysm formation?
Hypertension
What is the primary presentation of a subarachnoid haemorrhage?
Severe headache - ‘thunderclap headerache’
How does fresh blood appear on an unenhanced ct scan?
Bright white
Watershed infarct
Watershed cerebral infarctions, also known as border zone infarcts, occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus most vulnerable to reductions in perfusion.
Definition of stroke:
Stroke is a clinical syndrome defined as a rapidly developing neurological deficit (lasting over 24 hours or leading to death) with no apparent cause other than vascular.
What is the clinical presentation of stroke?
- Acute onset combination of:
- Face / arm / leg weakness or sensory loss
- Loss of co-ordination
- Speech disturbance
- Visual disturbance
ROSIER Scoring System:
Note: Blood sugar is not a part of the ROSIER system, but is important.
What are stroke mimics?
- similar presentation of stroke but not stroke.
• Seizures
• Syncope (hypotension)
- Sugar (hypo or hyper)
- Sepsis (+ previous stroke)
- Severe migraine
- Space occupying lesions
- Psychological
What are common differentials of stroke?
– Bell’s palsy
– Labyrinthitis
– Demyelination
– Space occupying lesion
– Worsening previous neurology with infection
Bell’s Palsy
Bell’s palsy is a type of facial paralysis that results in an inability to control the facial muscles on the affected side. Symptoms can vary from mild to severe. They may include muscle twitching, weakness, or total loss of the ability to move one or rarely both sides of the face.
Labyrinthitis
Labyrinthitis is an inner ear infection which affects your balance.
How does a seizure affect treatment and diagnosis of stroke?
Seizure at stroke onset is rare and a contraindication to thrombolysis.
Positive visual phenomena suggests what in cases of suspected stroke?
Positive visual phenomena more likely to be migraine.
How does TACS present?
How does LACS present?
How does PACS present?
PACS (Partial Anterior Circulation Stroke)
- Only two of three components of TACI syndrome or… • New higher cerebral dysfunction alone (e.g. dysphasia) or
- Motor and/or sensory deficit affecting one limb – or part of one limb (e.g. hand)
- May also have dysarthria/dysphagia
POCS
Posterior circulation stroke syndrome (POCS) refers to the symptoms of a patient who clinically appears to have had a posterior circulation infarct, but who has not yet had any diagnostic imaging (e.g. CT Scan) to confirm the diagnosis.
How does POCS present?
- Vertigo with ataxia and vomiting or
- Isolated hemianopia or
- Unilateral impaired coordination or
- Lower motor neurone cranial nerve signs – especially dysconjugate eye movements
- May also have dysarthria/dysphagia
How do you diagnose a TIA?
- Difficult
- Sudden onset, vascular territory
- Negative symptoms
- Isolated dizziness or vertigo or LOC: Unlikely
What can cause recurrent TIA’s?
- Haemodynamic (severe carotid stenosis)
- Lacunar TIAs (Capsular warning syndrome)
What is the carotid doppler?
A carotid Doppler is an imaging test that uses ultrasound to examine the carotid arteries located in the neck. This test can show narrowing or possible blockages due to plaque buildup in the arteries due to coronary artery disease.
- aims to prevent future stroke.
Define dysarthria.
Dysarthria often is characterized by slurred or slow speech that can be difficult to understand.
Define diplegia.
Diplegia is a spastic form of cerebral palsy with lower limbs more affected than upper limbs.
Define dysaesthesia.
An abnormal unpleasant sensation felt when touched, caused by damage to peripheral nerves.
Define dysdiadokinesia.
Impaired ability to perform rapid, alternating movements.
Clinical Bamford Classification of a Stroke
A stroke affecting where has the worst prognosis?
TACS - total anterior circulation stroke syndrome
Define TIA.
Stroke is a clinical syndrome defined as a rapidly developing neurological deficit lasting under 24hours with no apparent cause other than vascular.
Malignant mca syndrome
‘Malignant MCA infarction’ is the term used to describe rapid neurological deterioration due to the effects of space occupying cerebral oedema following middle cerebral artery (MCA) territory stroke.
What is the chance of recurrence in stroke?
10% chance in 1 week
18% chance in 3 months
What of strokes are due to infarcts (“blockages”).
80%
A 64 year old man presents to A&E following an episode of right arm weakness and difficulty speaking earlier that day that lasted 20 minutes then resolved. He has no significant past medical history, but smokes 10/day. His bp is 164/88. What is your impression from this story?
- Very unlikely to be a TIA
- Probable TIA - no risk of stroke in next 7 days
- Probable TIA - low risk of stroke in next 7 days
- Probable TIA - high risk of stroke in next 7 days
- Probable stroke
Probable TIA high risk of stroke in the next 7 days.
(10% is considered high risk).
Which of the following conditions can mimic some of the symptoms or signs of stroke? (select all that apply).
- Sepsis
- Seizures
- Space Occupying Lesions
- Uncomplicated hypertension
- Myocardial infarction
- Hypotension
- Migraine
- Hypoglycaemia
Seizures
Migraine
Hypoglycemia
Sepsis
Space occupying lesions
What does TACI stand for?
Total Anterior Circulation Involvement
Total Anterior Cerebral Involvement
Total Anterior Circulation Infarct
Total Anterior Cerebral Infarct
Terribly Awful Cranial Incident
Total Anterior Circulation Infarct
A 58 year old man presents with sudden onset expressive dysphasia and right face and arm weakness. An urgent CT head scan is unremarkable. How would you classify his stroke?
TACI
PACI
LACI
POCI
PACI
Remember, TACS is a full house, PACS is a part of it, LACS should not have any cortical (dysphasia in this case) or posterior (usually starts with a ‘D’) signs.
A 49 year old lady who suffers from hypertension and smokes 20/day presents after suddenly noticing that she has started walking into things. Examination reveals an isolated right homonymous hemianopia. What type of stroke is she likely to have suffered from?
POCS
Brainstem and cerebellar signs along with hemianopia.
- classical presentation of a POCS stroke.
Remember isolated hemianopia is located in the Occipital lobe, supplied by posterior cerebral artery; hence the right answer is POCS.
How does atrial fibrillation increase risk of having a stroke?
AFib puts patients at an increased risk for stroke because blood may not be properly pumped out of the heart, which may cause it to pool and form a clot. This clot can then travel to the brain and block the flow of blood to part of the brain which can result in a stroke.
Headache is often a prominent presenting feature of a stroke - TRUE OR FALSE?
FALSE
Remember, headache is rare after stroke and is a poor prognostic factor.
