Transient ischaemic attack and amaurosis fugax Flashcards
Define TIA
A brief episode of neurological dysfunction due to temporary focal cerebral ischaemia withOUT infarction
Generally how long does it take for symptoms of TIA to have resolved
24 hours
Very important to resolve quickly as without intervention, more than 1 in 12 patients will go on to have a stroke within a week, so prompt management is imperative
Epidemiology of TIA
Black ethnicity more at risk
More common in males
Pathophysiology of TIA
Commonest cause = Cerebral ischaemia, resulting in a lack of O2 and Nutrients to the brain resulting in cerebral dysfunction
In TIA, period of ischaemia is short lived - symptoms only last 5-15 mins usually after onset and then resolves before irreversible cell death occurs
If symptoms of TIA gradually progress and dont resolve, what pathology would this suggest
Demyelination
Tumour
Migraine
Causes of TIA
Atherothromboembolism from the carotid is chief cause
Cardioembolism resulting in Microemboli
Hyper-viscosity
Rare: Vasculitis or hypoperfusion
Causes of Microemboli by cardioembolism
Mural thrombus post-MI or in AF
Valve disease
Prosthetic valve
Examples of hyper-viscosity diseases that can result in TIA
Polycythaemia
Sickle cell anaemia
Extremely raised white cell count
Myeloma
Risk factors of TIA
Age (increases with age) Clotting disorder Combined oral contraceptive pill (increases clot risk) Diabetes Excess alcohol Heart disease - valvular, ischaemic or atrial fibrillation Hyperlipidaemia Hypertension Past TIA Peripheral arterial disease Polycythaemia vera Raised packed cell volume (PCV) Smoking Vasculitis (SLE, giant cell arthritis)
Long-term medical treatment of TIA
P2Y12 inhibitor e.g. Clopidogrel (antiplatelet drug)
Statin e.g. simvastatin
Describe ABCD2 score
Calculates risk of stroke after TIA: Age > 60yrs = 1 Blood pressure >140/90mmHg = 1 Clinical features: -unilateral weakness = 2 -speech disturbance without weakness = 1 Duration of symptoms: >1hr = 2 10-59mins = 1 Diabetes = 1
ABCD2 score:
What score strongly predicts a stroke and should be referred immediately to specialist?
What score predicts they should be referred to a specialist within 24 hours?
How quickly should a patient suspected of TIA be seen?
Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY
Score greater than 4 should be assessed by a specialist within 24hours
All patients with suspected TIA should be seen within 7 days
What other conditions (not in ABCD2 score) mean a person is at a high risk of a stroke
Atrial fibrillation
>1 TIA in one week
TIA whilst on anticoagulant
Pathophysiology of TIA
Most common cause of a TIA is cerebral ischaemia resulting in a lack of oxygen and nutrient to the brain
Results in cerebral dysfunction
HOWEVER
Period of ischaemia is short, with symptoms only lasting for 10-15 minutes after onset and then resolves before irreversible cell death occurs
Symptoms that gradually progress suggest a different pathology such as demyelination, tumour or migraine
General clinical presentation
SUDDEN loss of function, usually lasting for minutes only, with complete recovery and no evidence of infarction on imaging
What % of TIAs affect the anterior circulation (cartotid artery)
90%
What area of brain is supplied by anterior circulation
Frontal and medial part of cerebrum
Clinical presentation of TIA of anterior circulation
Weak, numb CONTRALATERAL leg +/- similar, if milder, arm symptoms Hemiparesis Hemi sensory disturbance Dysphasia Amaurosis fugax
What are:
Hemiparesis
Dysphasia
Hemiparesis - weakness on an entire side of the body
Dysphasia - language impairment
**What is Amaurosis Fugax
Sudden transient loss of vision in one eye
What causes amaurosis fugax
Temporary reduction in the retinal, opthalmic or ciliary blood flow leading to temporary retinal hypoxia
What is amaurosis fugax a sign of?
First clinical evidence of an ICA stenosis - warning sign of an imminent ICA territory stroke
What % of TIAs affect the posterior circulation (vertebrobasilar artery)
10%
Clinical presentation of TIA of posterior circulation
Diplopia Vertigo Vomiting Choking and dysarthria Ataxia Hemisensory loss Hemianopia vision loss Loss of consciousness (rare) Transient global amnesia Tetraparesis
What is ataxia
No control over body movement
What is diplopia
double vision
What is vertigo
feeling that your surroundings are moving
What is dysarthria
Unclear articulation of speech but understandable
What is transient global amnesia
episode of confusion/amnesia lasting several hours, followed by complete recovery
What is tetraparesis
muscle weakness affecting all 4 extremities
Is it possible to differentiate TIA from stroke
Impossible to differentiate until there is a full recovery (TIA)
Describe giant cell arteritis presentation
Monocular, temporary visual impairment normally presents
Raised ESR, thickening and tenderness of temporal artery
*Differential diagnosis
Hypoglycaemia
Migraine aura (symptoms spread and intensify over minutes, often with visual scintillations (sparkling/blinking))
Focal epilepsy (since limb shaking can occur in a TIA)
Intracranial lesion - tumour or subdural haemotoma
Syncope due to arrhythmia
Transient weakness of arm, hand or leg after a seizure
Retinal or vitreous haemorrhage
Giant cell arteritis
What is Todd’s paralysis
transient weakness of arm, hand or leg after a seizure
Diagnosis
Based on description
Bloods (FBC, ESR, Glucose, Creatinine, electrolytes, Cholesterol)
Carotid artery doppler ultrasound to look for stenosis/atheroma
ECG
CT or diffusion weighted MRI
Echocardiogram/cardiac monitoring to assess for a cardiac cause
What would you do to determine extent of stenosis
MR/CT angiography
Why is an ECG part of the diagnosis
Look for AF or evidence of MI ischaemia
What is the purpose of these blood tests in diagnosis of TIA:
FBC
ESR
Glucose
FBC - look for polycythaemia
ESR - will be raised in vasculitis
Glucose - to see if hypoglycaemic
How would you calculate risk of stroke after TIA
ABCD2 score
Describe ABCD2 score
Age > 60yrs = 1
Blood pressure > 140/90mmHg = 1
Clinical features:
Unilateral weakness = 2
Speech disturbance without weakness = 1 Duration of symptoms:
Symptoms lasting more than 1hr = 2 Symptoms lasting 10-59mins = 1
Diabetes = 1
Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY
Score greater than 4 should be assessed by a specialist within 24hours
All patients with suspected TIA should be seen within 7 days
How long until all patients with a suspected TIA should be seen
Within 7 days
What is the minimum score on ABCD2 that strongly predicts a stroke and what would you do?
Score greater than 6 strongly predicts a stroke and should be referred to a specialist IMMEDIATELY
What would happen is ABCD2 score is greater than 4 (but not over 6)
Score greater than 4 should be assessed by a specialist within 24hours
What other factors put patient at high risk of stroke, that are not in ABCD2 score
Atrial fibrillation
More than 1 TIA in one week
TIA whilst on an anticoagulant
Treatment
Control CVS risk factors
Antiplatelet drugs
Cardiac endarterectomy
ABCD2 score (and possible referral)
(Anticoagulant if they have AF, mitral stenosis or recent big septal MI e.g. WARFARIN)
Statin longterm e.g. SIMVASTATIN
Control cardiovascular risk factors
Do NOT DRIVE for at least 1 month following TIA
How long can a person not drive for following a TIA
At least 1 month
Treatment - Antiplatelet drug
ASPIRIN IMMEDIATELY
Then switch to Clopidogrel
If this is contraindicated, given aspirin with DIPYRIDAMOLE (↑cAMP and ↓ thromboxane A2)
P2Y12 inhibitor longterm e.g. CLOPIDOGREL
When would you give an anticoagulant like warfarin in treatment of TIA
If they have AF, mitral stenosis or recent big septal MI
Treatment - control of CVS risk factors
Antihypertensives such as ACE-inhibitor e.g. RAMIPRIL or angiotensin receptor blocker e.g. CANDESARTAN
Improve diet, stop smoking
