- Kennedy R Lees,
- Philip M W Bath,
- A Ross Naylor
Stroke or transient ischaemic attack is common and likely to be fatal or cause serious disability. A second stroke will not necessarily be of the same type as the initial event, although haemorrhages tend to recur. Patients with previous stroke commonly succumb to other vascular events, in particular myocardial infarction. Effective secondary prevention depends on giving attention to all modifiable risk factors for stroke as well as treating the causes of the initial stroke. Four questions should be answered:
Risk of recurrence after stroke or transient ischaemic attack
8% a year
Transient ischaemic attack
8% risk of stroke in first month
5% risk of stroke a year thereafter
5% risk of myocardial infarction a year
Modifiable risk factors for stroke
Diet: high salt and fats, low potassium and vitamins
Excess alcohol intake
Low physical exercise
Cholesterol concentration—at least in patients with coronary disease
Is it acute cerebrovascular disease?
The key features of acute cerebrovascular disease are focal neurological deficit, sudden onset, and absence of an alternative explanation. Abrupt onset of a dense hemiparesis before gradual improvement in a conscious patient rarely causes doubt, but conditions which commonly mimic stroke must be considered (see previous article BMJ 2000;320:920-3).
Is it ischaemic or haemorrhagic stroke?
Neither clinical history nor examination can reliably distinguish infarction from primary intracerebral haemorrhage. A small bleed can produce transient symptoms, although these rarely resolve within an hour.
Cerebral imaging is essential, and the choice and timing of the scan is important. Haemorrhage is immediately apparent on computed tomography, but its distinctive appearance becomes indistinguishable from infarction over a few weeks; for major symptoms, a computed tomogram taken within two weeks should still be diagnostic, but a small bleed may be missed after one week. …