Clinical Review - Stroke

By Dr Helen Hosker, GP and clinical commissioning lead for stroke, NHS Manchester, and Dr Pippa Tyrrell, honorary consultant in stroke medicine, Salford Royal Hospitals' Foundation Trust.

Section 1: Epidemiology and aetiology
Each year in the UK about 110,000 people have a stroke, with 25 per cent occurring in under 65-year-olds.

Stroke accounts for 11 per cent of all deaths and is the single largest cause of adult disability. There are about 900,000 people who have had a stroke living in England.

Stroke contributes to the gap in life expectancy in the most deprived areas and the population as a whole. In England the average prevalence of stroke is 1.6 per cent

CT angiograms pre-thrombolysis (left) and 24 hours following thrombolysis (right)

Clinical presentation
Stroke is defined as a clinical syndrome, of presumed vascular origin, typified by rapidly developing signs of focal or global disturbance of cerebral function lasting more than 24 hours (or less than 24 hours for TIA) or leading to death.

Modern imaging techniques have demonstrated that many TIAs have the same changes as ischaemic strokes. TIA can only have a retrospective diagnosis. Those with symptoms at the time of presentation should be presumed to be having a stroke.

There are two main types of stroke: ischaemic and haemorrhagic. About 80 per cent of strokes are ischaemic in nature.

Risk factors
Many strokes are preventable. The prevention of stroke is largely the same as that for the other vascular diseases. Risk factors can be divided into non-modifiable and modifiable medical and lifestyle.

Hypertension is a major risk factor for stroke. Treating to target levels of 130/80mmHg will result in a reduction in the number of strokes and acute cardiac events. Binge drinking alcohol can raise BP and is a risk factor for stroke.

Treating raised serum cholesterol and LDL with diet and statins will reduce atherosclerotic disease in the carotid and cerebral arteries. There is some evidence that statins can reduce carotid artery intimal wall thickness.

A low cholesterol level (LDL <1.8mmol/l) may be associated with an increased risk of haemorrhagic stroke.

AF and other arrhythmias that convey increased risk of thrombus formation significantly increase the risk of stroke. Treatment with anticoagulants must be considered to reduce the risk.

Aspirin 75-300mg or clopidogrel are alternatives if the risks associated with anticoagulation are considered too high. There are guides to assist in decision making.1,2

Categories of stroke and underlying cause
Ischaemic 80%
  • Atherothrombotic
  • Cardioembolic eg AF
  • Structural cardiac abnormalities (eg patent foramen ovale)

Haemorrhagic (primary intracerebral haemorrhage) 20%
  • Hypertension
  • Arteriovenous malformation
  • Trauma
  • Recreational drugs
Rare Causes
  • Central venous thrombosis
  • Cervical artery dissection: spontaneous or associated with neck injury
  • Antiphospholipid syndrome

 

Risk factors for stroke
Non-modifiable risk factors
Ethnic background: More common in black population
Sex: Male>female
Family history: First degree relative <60 years
Age: Risk increases with age
Modifiable risk

Medical

  • Hypertension factors
  • Hyperlipidaemia
  • AF
  • Diabetes

Lifestyle

  • Smoking
  • Exercise
  • Alcohol
  • Diet
  • Recreational drugs: cocaine and amphetamine

Section 2: Diagnosis
The onset of symptoms of stroke is rapid, over seconds or minutes, but may progress over the first 48 hours. Outside hospital, a validated tool such as FAST (see box) can be used to screen for stroke.

Medical emergency
Patients contacting a GP surgery or out-of-hours service with symptoms suggestive of stroke should be encouraged to call 999, or an emergency ambulance should be requested for them.

Ambulance service protocols now classify stroke with the same level of urgency as a possible heart attack.

In A&E departments, a validated assessment tool such as ROSIER,3 which involves a brief neurological examination including visual fields and blood glucose measurement, will support emergency referrals to acute stroke care.

Clinical features
Stroke is commonly associated with limb or facial weakness or numbness, speech disturbance (dysarthria or dysphasia), and other deficits of higher cortical function, for example, hemi-neglect.

Stroke affecting posterior circulation territory may present with sudden-onset vertigo and cerebellar or brain stem signs. Forty per cent of patients with stroke will initially have dysphagia. Visual field abnormalities may also be present.

Memory impairment or disturbance of cognitive function may present less acutely and be more difficult to diagnose.

The diagnosis can be difficult to make, particularly in those without obvious risk factors. Conditions that can mimic a stroke include hypoglycaemia, other metabolic disorders, migrainous hemiplegia, tumour, encephalopathy and sepsis.

Investigations
Patients with acute stroke need urgent specialist investigation. Brain scanning is essential to exclude haemorrhage and 'stroke mimics'. CT scanning is the most commonly available, is quick and is well tolerated.

Those presenting within three hours who might be eligible for thrombolysis, those on anticoagulants or with other bleeding disorders, or with impaired level of consciousness need to be scanned immediately.

For all others where a stroke is suspected a CT brain scan should be carried out as soon as possible, certainly within 24 hours.

Routine blood tests including FBC (with platelet count), U&Es, blood glucose and lipid profile should be arranged. Patients taking warfarin need their INR measured immediately.

All patients need an ECG to exclude an arrhythmia such as AF, and any underlying cardiovascular disease such as ischaemia or left ventricular hypertrophy. An echocardiogram will exclude a structural heart lesion or mural thrombus if suspected and a transoesophageal echo may be necessary to exclude a patent foramen ovale.

Carotid imaging, usually using Doppler ultrasound, should be performed to exclude a significant carotid stenosis where the stroke is in the carotid artery territory. More complex imaging such as CT perfusion, CT angiography, MR or MR angiography may be required, particularly in younger patients or where the diagnosis or cause of stroke may be in doubt.

Fast (face, arm, speech, test) tool
Facial weaknessCan the person smile?
Has their mouth or eye drooped?
Arm weaknessCan the person raise both arms?
Speech problemsCan the person speak clearly and understand
what you say?
Test all three symptomsStroke is a medical emergency
Call 999 - early treatment can prevent further brain damage

Section 3: Management

Early treatment
Early identification of stroke patients and transfer to specialist care, preferably an acute stroke unit, means assessment and investigations can be delivered in a structured and timely manner. The evidence is that care on a dedicated unit reduces mortality and improves outcomes for all stroke patients.4

Patients who present within three hours of symptom onset and who have no evidence of haemorrhage on CT scan may be eligible for thrombolysis with alteplase.5

This treatment should only be administered by specialists on a unit with trained staff and patients entered in a research study. Restoration of the blood supply can dramatically reduce the extent of brain ischaemia and resulting disability.

Acute care
Acute stroke care should include monitoring blood glucose and BP, and maintaining within limits to avoid high and low values. Treating hypoxia and pyrexia and preventing dehydration can help salvage the ischaemic penumbra surrounding the initial area of infarction and limit the amount of brain damaged.

Following exclusion of haemorrhage, all patients should be given aspirin 300mg as soon as possible or 24 hours following treatment with alteplase.

Those with haemorrhagic stroke taking warfarin need immediate reversal of warfarin using prothrombin complex concentrate and vitamin K.

Assessment of vascular risk factors and appropriate management should be instigated as soon as possible, although uncertainty remains about when to treat hypertension in the context of acute stroke.

Some patients may require specialist input from neurology, neuroradiology, neurosurgery and specialist cardiology.

Most patients will have a combination of disabilities following a stroke. Initial assessments should commence within a few hours and include swallowing, manual handling - including an ability for sitting balance and mobility - continence, pressure area care, the capacity to understand and follow instructions, the capacity to communicate their needs, nutritional status, and the ability to hear and see.

TIA
Any patient where TIA is suspected must be given aspirin 300mg immediately.6 The risk of a stroke should be calculated using the validated ABCD2 tool (see box). Patients with a score ≥4 are at high risk of a stroke within the next month and should be seen and assessed within 24 hours of the onset of symptoms. Low-risk patients should be assessed within a week.

Assessment should include any correctable causes and vascular risk factors. Those with severe carotid stenosis should be referred to a vascular surgeon and carotid endarterectomy performed within two weeks.

ABCD2 SCORE FOR STROKE RISK AFTER TIA7
Age≥60 yrs1 point
BP≥140/90mmHg1 point
Clinical featuresSpeech impairment without weakness1 point
Unilateral weakness2 points
Duration of symptoms10-59 mins1 point
≥60 mins2 points
DiabetesYes1 point

Section 4: Prognosis and follow up
Patients and their carers need to be aware of the symptoms of stroke and the appropriate urgent medical response in the event of a further event.

Rehabilitation
Patients with any impairment should receive a full multidisciplinary assessment by staff trained in the care of stroke patients, using agreed protocols and tools, within five working days. All patients should be screened for anxiety and depression as part of the initial assessments and during follow up.

Patients and carers should be involved in setting realistic treatment goals.

A multidisciplinary rehabilitation team should include physiotherapists, occupational therapists, speech and language therapists, dieticians and psychologists.

Mobility problems and ability to perform activities of daily living should be treated by supervised programmes of activities.

Swallowing problems may require a modified diet, such as pureed foods or PEG feeding. Patients with dysphasia or dysarthria can be taught techniques to improve function or be given communication aids.

Patients with mood disorders, cognitive impairments including attention, concentration and difficulties in planning and sequencing tasks - executive dysfunction - can be taught compensatory strategies.

Most recovery takes place by six months, although further improvements are possible. Rehabilitation should continue for six months, or until the pre-stroke level of function has been achieved or is stable.

Secondary prevention
Each patient should have a comprehensive assessment of their risk factors for stroke. Patients should be provided with a personal plan in a suitable format that takes account of their disabilities and personal characteristics. This should start in the hospital and continue long term.

Aspirin (50-300mg daily) and modified-release dipyridamole 200mg twice daily should be started two weeks following an ischaemic stroke. If dipyridamole is not tolerated, aspirin alone is suitable, with a proton pump inhibitor if required. Clopidogrel is an alternative when there is true intolerance to aspirin.

The risk of stroke correlates with BP and following a stroke some would advocate a 'the lower the better' approach, provided it is tolerated. The target BP of 130/80mmHg is derived from cardiac studies. For those with severe bilateral internal carotid artery stenosis a higher target may be appropriate.

Services that support lifestyle risk reduction need to be able to accommodate those with post stroke disabilities, for example communication problems or mobility problems. Smoking cessation must be actively encouraged.

Exercise advice should be tailored to the individual and incorporate aerobic activity if possible. Dietary advice for those who are obese is important in reducing the risk of diabetes in the future and potential difficulties with manual handling.

Resources

References

1. NICE Clinical Guideline 36: The management of atrial fibrillation. www.nice.org.uk

2. Gage BF, Waterman AD, Shannon W, et al. Validation of clinical classification schemes for predicting stroke: results from the national registry of atrial fibrillation. JAMA 2001; 285(22): 2,864-70.

3. Nor A, Davis J, Sen B et al. The recognition of stroke in the emergency room (ROSIER) scale. Lancet Neurol 2005; 4: 727-34.

4. NICE Clinical Guideline 68: Stroke: Diagnosis and initial management of acute stroke and transient ischaemic attack.

5. NICE Technical Appraisal Guidance 122: Alteplase for the treatment of ischaemic stroke.

6. Rothwell P M, Giles M F, Chandratheva A, et al. Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study): a prospective population-based sequential comparison. Lancet 2007; 370: 1,432-42.

7. Johnston S, Rothwell P M, Nguyen-Huynh M N, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007; 369: 283-92.

Further reading

For an archive of all GP clinical reviews visit www.healthcarerepublic.com/clinical/GP

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