19th July 2023

Stroke

Background

Stroke is defined as ‘a clinical syndrome consisting of rapidly developing signs of focal (or global) disturbance of cerebral function, lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin.’

Identifying the underlying aetiology of the stroke is very important in order to provide appropriate treatment to reduce the risk of further events.

Ischaemic stroke

The majority of strokes are due to cerebral infarction. Causes of infarction include atherosclerosis, cardioembolic disease, vessel disease, e.g. vasculitis, dissection, venous thrombosis and haematological disease, e.g. sickle cell anaemia and hypercoagulable states. In some cases, there will be no cause identified.

Risk factors include increasing age, personal history of ischaemic stroke, hypertension, smoking, diabetes mellitus, atrial fibrillation, carotid artery stenosis, sickle cell disease and dyslipidaemia.

Classification

Table 1: Oxford Community Stroke Project (Bamford)

Haemorrhagic stroke

Rapidly developing neurological dysfunction due to a focal intraparenchymal or intraventricular collection of blood. The main risk factor for haemorrhagic stroke is hypertension. Others include increasing age, excess alcohol intake, smoking and reduced physical activity.

Assessment

Validated screening tools should be used in assessing patients who present with a possible stroke. For example, in the community use FAST (Face Arm Speech Test), and in the emergency department the ROSIER score (Recognition of Stroke in the Emergency Room) can be used, shown in Table 2. Both should be used once hypoglycaemia has been excluded.

Table 2: Recognition of Stroke in the Emergency Room

Once a clinical diagnosis of stroke has been made, it is useful to assess severity using the National Institutes of Health Stroke Scale (NIHSS), which can help guide treatment.

Investigation

Key initial investigations include full blood count, urea and electrolytes, glucose, clotting screen and group and save.

Urgent brain imaging with non-contrast CT should be performed to exclude intracerebral haemorrhage. In the very early stages of an ischaemic stroke, there may not be any visible CT changes; therefore, a normal CT scan does not exclude stroke. Further imaging with either CT-angiography or MR-angiography will be required if the patient is being considered for thrombectomy or if there is clinical suspicion of dissection.

Following a diagnosis of stroke, further investigations are carried out to identify the underlying cause. These may include serial ECGs, ECG Holter monitor, carotid imaging, echocardiogram, vasculitis screen and thrombophilia screen. Investigations should be targeted based on the clinical picture and the most likely differential diagnoses.

Management

Ischaemic stroke

Thrombolysis with alteplase is recommended if treatment can be started as soon as possible within 4.5 hours of onset of stroke symptoms and intracerebral haemorrhage has been excluded. It is important to be aware that there are contra-indications to thrombolysis.

Thrombectomy should be offered in addition to thrombolysis (unless contra-indicated) as soon as possible and within 6 hours of onset of stroke symptoms to those with:

• acute ischaemic stroke and
• confirmed occlusion of the proximal anterior circulation demonstrated on imaging

Thrombectomy can be offered to patients known to be well in the previous 6-24 hours, including ‘wake-up’ strokes, with:

• an acute ischaemic stroke and confirmed occlusion of the proximal anterior circulation demonstrated on imaging and
• potential to salvage brain tissue as shown by imaging, e.g. CT-perfusion or diffusion weighting MRI.

Thrombectomy (and thrombolysis, unless contraindicated) can be considered for those known to be well up to 24 hours previously, including ‘wake-up’ strokes, with

• an acute ischaemic stroke and confirmed occlusion of the proximal posterior circulation demonstrated on imaging and
• potential to salvage brain tissue as shown by imaging, e.g. CT-perfusion or diffusion weighting MRI

If a patient is not suitable for thrombolysis or they are outside the 4.5-hour window, they should be offered 300mg aspirin as soon as possible. This should be continued for 2 weeks, after which clopidogrel 75mg is recommended for secondary prevention.

Haemorrhagic stroke

Patients with intracerebral haemorrhage in association with anticoagulant treatment should be offered urgent reversal, if available.

Blood pressure should be controlled in accordance with local protocols. NICE recommends a target systolic blood pressure between 130-140mmHg within 1 hour of starting treatment and to be maintained for at least 7 days. Rapid blood pressure lowering should not be offered to people with any of the following: underlying structural cause for intracerebral bleed, GCS <6, are going to have early neurosurgery or have a massive haematoma with a poor prognosis.

Neurosurgical review will be needed to assess if the patient is likely to benefit from neurosurgery.

Secondary prevention

In addition to acute management, it is also important to identify and address risk factors for secondary prevention.

Diet and lifestyle factors should be addressed, as these can contribute to cardiovascular risk.

Further issues to target, if relevant, include hypertension, hyperlipidaemia, blood glucose control in diabetes, atrial fibrillation and carotid artery stenosis.