Transient Ischaemic Attack Flashcards
1
Q
Define TIA
A
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
2
Q
TIA epidemiology
A
- 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
3
Q
Aetiology - biggest cause
A
29% = cardioembolic event
4
Q
4 main aetiologies of TIA
A
- Insitu thrombosis of an intracranial artery or artery-to-artery embolism (16%)
- Cardioembolic event (36%)
- Small vessel occlusion (16%)
- Occlusion (3%)
- Uncertain mechanism (36%)
5
Q
Causes of small vessel occlusion
A
- Diabetes
- HTN
- Microatheroma
- Fibrinoid necrosis
- Lipohyalinosis
6
Q
Causes of occlusion
A
- Hypercoagulability
- Dissection
- Vasculitis
- Vasospasm
- Sickle cell
7
Q
Normal cerebral blood flow
A
> 50mL/100g/min
8
Q
When CBF falls between 20 and 50
A
Brain compensates by increasing oxygen extraction
9
Q
When CBF falls below 20
A
Neurological deficits
10
Q
When CBF falls below 15
A
Neuronal death
11
Q
Define ischaemic neuronal injury
A
- Cytotoxic oedema
- Influx of water into intracellular space
12
Q
Classification of TIA
A
- Large artery artherosclerosis
- Cardioembolism
- Small vessel occlusion
- Other determined aetiology
- Undetermined aetiology
13
Q
Signs and symptoms of a TIA
A
- Weakness
- Numbness
- Paralysis
- Slurred speech
- Difficulty understanding others
- Blindness (1 or both)
- Double vision
- Sudden, severe headache
14
Q
Important lab tests for TIA assessment
A
- FBC, chemistry, glucose, PT
15
Q
What symptoms make a TIA more likely
A
- Rapid resolving
- Single vascular territory
- Absent alternative
