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Transient Ischaemic Attack (TIA) (Risk Factors (Past TIA, Raised packed…
Transient Ischaemic Attack (TIA)
Key Facts
Definition - A brief episode of neurological dysfunction due to temporary focal cerebral ischaemia without infarction
Symptoms have generally resolved within 24 hours
Epidemiology
More common in MALES than females
Black ethnicity are at greater risk due to their hypertension and atherosclerosis predisposition
15% of first strokes are preceded by TIA, they are also a foreshadowing of an MI
Aetiology
Cardioembolism resulting in microemboli form - Mural thrombus post-MI or in AF, valve disease, prosthetic valve
Hyperviscosity - polycthaemia, sickle cell anaemia
Atherothromboembolism from the carotid is the CHIEF CAUSE
Can result from hypoperfusion - most important in younger people
Small vessel occlusion
Risk Factors
Past TIA
Raised packed cell volume (PCV)
Heart disease - valvular, ischaemic or atrial fibrillation
Diabetes
Peripheral arterial disease
Smoking
Polycythaemia vera
Combined oral contraceptive pill (since increase risk of clots)
Hyperlipidaemia
Hypertension
Age - risk increases with age
Clotting disorder
Excess alcohol
Vasculitis
Pathophysiology
The commonest cause of a TIA is cerebral ischaemia resulting in a lack of O2 and nutrients to the brain resulting in cerebral dysfunction - however in a TIA this period of ischaemia is short-lived, with symptoms usually only lasting a maximum of 5-15 minutes after onset, and then resolves with before irreversible cell death occurs
Symptoms that gradually progress suggest a different pathology such as demyelination, tumour or migraine
Clinical Presentation
Site of TIA is often suggested by symptoms
90% of TIA's affect the anterior circulation (carotid artery)
Hemiparesis - weakness on an entire side of the body
Hemi sensory disturbance
Occlusion may cause a weak, numb CONTRALATERAL leg +/- similar, if milder, arm symptoms
Supplies the frontal and medial part of the cerebrum
Dysphagia (language impairment)
Amaurosis fugal - sudden transient loss of vision in one eye
SUDDEN loss of function, usually lasting for minutes only, with complete recovery and no evidence of infarction on imaging
10% affect the posterior circulation (vertebrobasillar artery)
Ataxia - no control of body movement
Hemisensory loss
Choking & dysarthria (unclear articulation of speech but understandable)
Hemianopia vision loss
Vomiting
Loss of consciousness (rare)
Vertigo - the feeling that your surroundings are moving
Transient global amnesia
Diplopia - double vision
Tetraparesis - muscle weakness affecting all 4 extremities
Differential Diagnosis
Syncope due to arrhythmia
Todd's paralysis - transient weakness of arm, hand or leg after a seizure
Intracranial lesion - tumour or subdural haemotoma
Retinal or vitreous haemorrhage
Hypoglycaemia, migraine aura, focal epilepsy
Giant cell arteritis
Raised ESR, thickening and tenderness of temporal artery
Monocular, temporary visual impairment usually
Until there is a full recovery it is impossible to differentiate from a stroke
Treatment
Anticoagulant if they have AF, mitral stenosis or recent big septal MI
Statin longterm
Antiplatelet drugs - aspirin immediately, P2Y12 inhibitor long term
Control cardiovascular risk factors - antihypertensives (ACEi/ARB), improve diet & stop smoking
ABCD2 score risk of stroke after TIA
DO NOT DRIVE FOR AT LEAST 4 WEEKS FOLLOWING TIA
Diagnosis
MRI/CT angiography if stenosis to determine extent
ECG - look for AF or evidence of MI ischaemia
Carotid artery doppler ultrasound to look for stenosis/atheroma
CT or diffusion weighted MRI
Bloods
Glucose - to see if hypoglycaemic
Creatinine, electrolytes
ESR - will be raised in vasculitis
Cholesterol
FBC - look for polycythaemia
Echocardiogram/cardiac monitoring to assess for a cardiac cause
Often solely based on its description