Initial assessment of acute stroke and transient ischaemic attack

Clinical assessment is the cornerstone of diagnosing acute stroke and transient ischaemic attack (TIA). Urgently refer the patient to hospital for rapid expert clinical assessment (including prognosis), immediate treatment and an early start to secondary prevention.

About 30% of patients with suspected stroke have a 'stroke mimic’ (eg tumour, subdural haematoma, migraine, hypoglycaemia, postictal paralysis, cerebral abscess)—this must be identified by clinical assessment, brain imaging and other tests.

Urgent brain imaging is central to assessing suspected stroke/TIA and identifying stroke mimics. Computed tomography (CT) scanning can identify intracerebral haemorrhage, and often detects early signs of ischaemia. Magnetic resonance imaging (MRI; especially diffusion-weighted imaging) is more sensitive for detecting ischaemia, so is most helpful in TIA and posterior circulation events. Computed tomography angiography can show occluded intracranial vessels. Computed tomography or magnetic resonance perfusion studies show potentially salvageable brain tissue.

The first step in clinical assessment is to confirm the diagnosis of stroke by ruling out mimics and determining whether the patient has an intracerebral haemorrhage or ischaemic stroke. If ischaemic, the next step is to decide whether the patient is suitable for reperfusion therapy. As reperfusion is time-critical, establishing the time of onset of the stroke (or the last time when the patient was seen to be well) is essential. Imaging the brain to look for occluded vessels or perfusion abnormalities can indicate that endovascular thrombectomy is required. Decisions on reperfusion therapy need expert involvement, and must consider patient factors (eg severity of stroke, preferences for treatment).

The final step in initial assessment is to determine the cause of the stroke. Most ischaemic strokes are due to atherosclerosis (see also a description of rarer causes). Use clinical features and brain imaging to determine the area of brain affected (eg anterior or posterior circulation, cortical or subcortical). This can suggest the cause and guide further investigation. For example, subcortical syndromes (eg lacunar stroke) are often due to small vessel disease, while cortical syndromes should prompt a search for cardiogenic emboli or carotid stenosis.

All patients with a confirmed diagnosis of stroke should be admitted for care in a dedicated stroke unit. Organised care in a multidisciplinary stroke unit reduces mortality and dependency, increases the likelihood of discharge to home, and does not increase the length of hospital stay. These benefits are independent of age, gender, and type or severity of stroke.