Transient ischaemic attack (TIA) - Cerebrovascular disease

Transient ischaemic attack (TIA)

Definition

Non-traumatic focal neurological deficit due to cerebral ischaemia lasting less than 24 hours with a complete clinical recovery. TIAs may recur or precede a stroke.

Aetiology/pathophysiology

90% of transient ischaemic attacks are caused by ex-tracranial thromboembolic disease within the great vessels, the carotid or vertebral arteries, or mural thrombi following a myocardial infarction.

Clinical features

The onset of a TIA is identical to that of a stroke, but tends to last minutes or hours. The site of the lesion is often suggested by the clinical pattern. Common symptoms include weakness, numbness, and transient monocular loss of vision (amaurosis fugax) or other visual disturbance. Evidence of vascular disease such as bruits, valvular heart disease, and other risk factors such as hyper-tension, arrhythmias, hypercholestrolaemia or diabetes mellitus should be sought. Important differentials include hypoglycaemia, focal epilepsy (usually with a preceding jerking of one or more limbs, and a post-ictal phase) and migraine (symptoms may precede or follow the onset of headache).

Investigations

These are as for stroke. CT head may distinguish between TIA, stroke and haemorrhage. However, <24 hours after a stroke, the CT may still be normal.

Management

All patients should be on an antiplatelet agent such as aspirin. Other treatments include antihypertensives, statin cholestrol lowering agents, and management of cardiac arrhythmias, heart disease or diabetes mellitus.

In patients with symptomatic TIAs with an underlying significant carotid stenosis (>70%), surgery is indicated with carotid endarterectomy (see above).

Prognosis

Five years after a transient ischaemic attack

1 in 6 patients will have had a stoke.

1 in 4 patients will have died usually from a stroke or heart disease.