Transient Ischaemic Attack (TIA) Flashcards
What is the definition of a TIA?
A rapidly developing focal disturbance of brain function of presumed vascular origin that resolves completely within 24 hours.
Explain the aetiology of TIAs?
- It is usually EMBOLIC but may be thrombotic
- Most common source of emboli = CAROTID atherosclerosis
- Emboli can also arise from the heart:
Atrial fibrillation
Mitral valve disease
Atrial myxoma
NOTE: clots from the right side of the circulation can cause a stroke if there is a septal defect (e.g. PFO)
What are the risk factors involved with TIAs?
Hypertension
Smoking
Diabetes mellitus
Heart disease (valvular, ischaemic, atrial fibrillation)
Peripheral arterial disease
Polycythaemia rubra vera
COCP
Hyperlipidaemia
Alcohol
Clotting disorders
What is the epidemiology of TIAs?
More common with increasing age
More common in men
15% of stroke patients would have experienced a previous TIA
What should be done to any patient suspected of a TIA?
ANY PATIENT presenting with acute neurological symptoms that resolve completely within 24 hours (i.e. a suspected TIA) should be given 300 mg aspirin immediately and assessed urgently within 24 hours
How long do TIAs normally last?
TIAs usually last 10-15 mins (but can be anything from a few minutes to 24 hours)
What are the clinical features of TIAs
Clinical features depend on the part of the brain affected:
Carotid Territory:
- Unilateral
- Most often affect the MOTOR AREA: weakness an arm, leg or one side of the face
- Dysarthria
- Broca’s dysphasia (if Broca’s area is involved)
- Amaurosis fugax (painless fleeting loss of vision caused by retinal ischaemia)
Vertebrobasilar Territory:
- Homonymous hemianopia (if ophthalmic cortex is involved)
- May be bilateral visual impairment
- May be hemiparesis, hemisensory symptoms, diplopia, vertigo, vomiting, dysarthria, dysphagia or ataxia
- Ask about weakness, facial drooping, gait disturbance, confusion, memory loss, dysarthria or abnormal behaviour
- Check for simultaneous cardiac symptoms (e.g. palpitations)
What are the signs of TIA on physical examination?
Neurological examination may be NORMAL because the TIA may have resolved by the time you do it
Check pulse for irregular rhythm (AF)
Auscultate the carotids to check for bruits (carotid atherosclerosis)
What investigations may be appropriate when suspecting TIA?
In primary care the following investigations can be requested:
- Urinalysis (check for glycosuria)
- FBC, U&Es, Lipids, LFTs, TSH
- ECG (check for AF or previous MI)
Secondary care investigations can involve an unenhanced CT - if there’s a possibility of a haemorrhage (eg if patient is anticoagulated or has a bleeding disorder)
Lastly you can investigate for the source of emboli
- ECG (24 hr tape or cardiac monitoring may be considered if paroxysmal atrial fibrillation is suspected)
- Doppler ultrasound of carotid and vertebral arteries
What is the management plan for TIAs?
- Patients with acute neurological symptoms that resolve completely within 24 hrs should be given 300 mg aspirin immediately and assessed urgently within 24 hrs
- Patients with confirmed TIA should receive:
Clopidogrel - 300 mg loading dose and 75 mg thereafter
High-Intensity Statin Therapy - e.g. atorvastatin 20-80 mg
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Secondary prevention can involve:
Antiplatelets
Antihypertensives
Lipid-modifying treatments
Management of AF
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Assesment of future stroke risk in TIA pts = ABCD2 score
What are the potential complications of TIAs?
Recurrent TIAs
Strokes
What is the prognosis of patients with TIAs
VERY HIGH RISK of STROKE in the first month after the TIA and up to 1 year afterwards