Transient Ischaemic Attack Flashcards
Define TIA
Transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia, without acute infarction
Temporary, completely reversible, most resolve within 1 hour
TIA epidemiology
- Prevalence increases with age
- M > F
- Blacks > Caucasians
- Exact number of TIAs difficult to establish due to mimic conditions and many going unrecognised and not presenting to hospital
Aetiology - biggest cause
29% = cardioembolic event
4 main aetiologies of TIA
- Insitu thrombosis of an intracranial artery or artery-to-artery embolism (16%)
- Cardioembolic event (36%)
- Small vessel occlusion (16%)
- Occlusion (3%)
- Uncertain mechanism (36%)
Causes of small vessel occlusion
- Diabetes
- HTN
- Microatheroma
- Fibrinoid necrosis
- Lipohyalinosis
Causes of occlusion
- Hypercoagulability
- Dissection
- Vasculitis
- Vasospasm
- Sickle cell
Normal cerebral blood flow
> 50mL/100g/min
When CBF falls between 20 and 50
Brain compensates by increasing oxygen extraction
When CBF falls below 20
Neurological deficits
When CBF falls below 15
Neuronal death
Define ischaemic neuronal injury
- Cytotoxic oedema
- Influx of water into intracellular space
Classification of TIA
- Large artery artherosclerosis
- Cardioembolism
- Small vessel occlusion
- Other determined aetiology
- Undetermined aetiology
Signs and symptoms of a TIA
- Weakness
- Numbness
- Paralysis
- Slurred speech
- Difficulty understanding others
- Blindness (1 or both)
- Double vision
- Sudden, severe headache
Important lab tests for TIA assessment
- FBC, chemistry, glucose, PT
What symptoms make a TIA more likely
- Rapid resolving
- Single vascular territory
- Absent alternative
What should one do if there is a single ongoing deficit
Treat for stroke - consider thrombolysis
2 things involved in a TIA follow-up
- Cardiac monitoring (arrhythmia)
- Echocardiogram (cardioembolism)
TIA usually present with ……. symptoms
Negative
Negative symptoms presenting with TIA
- Loss of power or sensation
- Aphasia
Risk factors for TIA
- AF
- Vascular disease
- Carotid stenosis
- Congestive HF
- HTN
- Diabetes
- Smoking
- Increased age
- Alcohol
- Hyperlipidaemia
- Chronic renal failure
- Hypercoagulability
- Miscarriage history
- Thrombus history
Differential diagnosis for TIA
- Hypoglycaemia
- Severe hyponatraemia
- Hypokalaemia
- Hypercalcaemia
- Seizure with post-seizure (Todd’s) paralysis
- Complex migraines
- Space occupying lesion (haemorrhage, abscess, mass)
- Conversion disorder
What does the ABCD2 score measure
Predicts the risk of stroke following TIA
A in ABCD2
Age >60 (1)
B in ABCD2
BP >140, >90 (1)
C in ABCD2
Clinical unilateral weakness (2) or clinical speech deficit (1)
D in ABCD2
- Duration >60 (2), 10-59mins (1)
- Diabetes (1)
What does the national institute of health (NIH) stroke scale measure
- Measure severity of ischaemic injury
Components of the NIH stroke scale
- LOC
- Best gaze
- Visual field
- Facial palsy
- Motor arm and leg drift
- Limb ataxia
- Sensory (pinprick) test
- Aphasia
- Dysarthria
- Inattention
Main treatment for TIA - primary atherosclerotic disease
Antiplatelet
Main treatment for TIA - primary cardioembolism
Anticoagulant
Treatment for risk factor modification for TIA
- Statin
- Antihypertensive
- Lifestype modification
- Stenting
Antiplatelet therapy
- Aspirin
- Aspiring + dipyridamole
- Clopidogrel
- Clopidogrel + aspirin
- Tricagrelor
Anticoagulant therapy
- Warfarin
- Dabigatron
- Rivaroxaban
- Edoxaban
TIA and statin therapy
- Provides benefit acutely after ischaemia (start statin on presentation of symptoms)
- Decrease risk of second event or stroke
- Recommended to everyone - high intensity dosing <75yo and moderate intensity dosing >75yo
Complications of TIA
- Stroke
- MI
