Stroke Solutions

By: Lisa Kelly & Dr. Desmond O'Neill

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Stroke is a devastating condition which remains the third highest cause of death in Ireland after heart disease and cancer. Over 8,500 people were admitted to hospital following acute stroke in the Republic of Ireland in 1997, the last year for which figures are available.

The in-patient mortality is 21% in the ERHA region due to both the high rate of infection and thromboembolism and sequelae of the stroke itself. Morbidity is also very high with an estimated 30,000 people suffering residual disability ranging from mild dysarthrias to hemiparesis. 75% of strokes occur in people over 75 years of age and the recurrence rate is between 10% and 15%, highest in the first ten to thirty days after the initial stroke.

Risk Factors for Ischaemic Stroke
Non-modifiable
Modifiable

~ Age
~ Gender
~ Race
~ Ethnicity

~ Hypertension
~ Cigarette smoking
~Diabetes mellitus
~ Life-style factors;

- obesity,
- physical inactivity
- diet,
- emotional stress
~Cardiac disease;
- atrial fibrillation,
- valve disease,
- myocardial disease,


~ Cartoid artery disease
~ Previous stroke;
-
(overt or silent)
~ Previous TIA
~ Hypercholesterolaemia;
role remains uncertain but linked to ischaemic heart disease and cartoid artery disease

NEW DIRECTIONS

Stroke has not been seen as an emergency of the very highest priority but this is changing for two reasons. The first is that we know that early treatment of stroke in a Stroke Unit is very effective: the Irish Heart Foundation has now recommended that every general hospital should have a Stroke Unit. There are Stroke Units in Tallaght Hospital, St. Camillus' hospital in Limerick and Units planned for Blanchardstown, Beaumont and the Mater Hospitals. We have only to treat 14 people in a Stroke Unit to save a life or prevent serious disability.

The second reason is that thrombolysis is likely to become a treatment option for stroke in Ireland but with a very short 'time-to-needle' from the stroke, a maximum of three hours! An initiative to improve ambulance and health response to stroke has been launched in the UK, Improving Response (IRIS) which seeks to inform lay people and professionals of all stages of stroke care of the need to treat stroke as an acute emergency.

TYPES OF STROKE

There are two subtypes of stroke; ischaemic and haemorrhagic. Acute ischaemic stroke accounts for 85% of events and is due to a cardioembolism or associated with cartoid artery or heart disease in a majority of cases. We cannot tell the difference between the two clinically, and since the treatments are different, every patient with stroke needs a brain scan within the first 48 hours. There are many risk factors for ischaemic stroke but the most important modifiable risk is of untreated hypertension and smoking.

DIAGNOSIS

Stroke is defined by the WHO as 'Rapidly developing clinical signs and symptoms of focal and at times global loss of cerebral function lasting more than 24 hours or leading to death within 24 hours with no cause other than vascular origin.' If signs and symptoms last less than 24 hours with no residual deficit then the diagnosis is of a Transient ischaemic Attack (TIA).

Many rapid assessment tools have been developed for the early diagnosis of stroke such as the Face, Arm, Speech Test (FAST) developed in the Freeman Hospital, Newcastle. This assesses three parameters allowing rapid and accurate diagnosis of stroke by paramedics.
Face:
Facial asymmetry, new drooping of the mouth, inability to show teeth when smiling.
Arm:
Inability to raise affected arm above shoulder level.
Speech:
Difficulty with following simple commands or with articulation.

A study of 222 patients referred to the Freeman Hospital with suspected stroke using this simple scale showed paramedics had a very high level of accuracy (80%) in diagnosing acute stroke.

The signs and symptoms of stroke vary dependent on the site of occlusion and the degree to which the blood flow is interrupted. The classical presentation is of a sudden onset of hemiparesis in any individual of an atherosclerotic age group. Virtually any combination of symptoms, of brain dysfunction can occur however with combinations of hemparesis, hemisensory loss and hemianopia. If the dominant cerebral hemisphere is involved then disorders of language can occur in expressive and receptive dysphasias. Other problems including various perceptual deficits can occur including agnosias (difficulty interpreting sensory data from the environment or one's body) and apraxias (difficulties in formulating movements or sequencing activities) for example the patient may not be able to dress when asked to do so but is able to carry out all the individual movement required to do so.

Glossary of common stroke terms
Hemiparesis
Weakness affecting one side of the body
Sequelae
A condition following as a consequence of a disease
Hemianopia
Loss of vision for one half of the visual field of one or both eyes
Dysphagia
Swallowing difficulty
Hypoglycaemia
An abnormally low concentration of glucose in the circulating blood
Pyrexia
Feverishness
Stenosis
Narrowing of the arteries
Dysarthia
Slowed, slurred or distorted speech caused by weakening of the tongue or other muscles essential to speech
Quadriparesis
Partial weakness of all four limbs
Diplopia
Vertical double-vision in which one image is seen at a higher level than the other

INTRA-CEREBRAL HAEMORRAGE

Intra-cerebral haemmorrage and sub-arachnoid haemmorage account for 15% of total strokes. Sub-arachnoid haemmorage is most commonly due to rupture of aneurysms or arterovenous malformation. This may present with sudden severe unexplained headache often described by patients as 'the worst headache of my life'. Headache is commonly associated with loss of consciousness and vomiting. Enlarging aneurysms however can also cause a variety of neurological deficits including a palsy of the third cranial nerve (unilateral dilated pupil with loss of light reflex) or sudden onset hemiparesis or aphasia.

Risk factor for intra-cerebral bleed are most commonly hypertension, bleeding into an infarct or tumour and rupture of an aneurysm. The possibility of this diagnosis must be kept in mind in dealing with any patient on anti-coagulants. Use of cocaine and amphetamines are more unusual causes to be considered in younger patients.

TRANSIENT ISCHAEMIC ATTACKS

In a TIA all signs and symptoms resolve within 24 hours and often patients will not present to hospital. However 12% of patients experiencing a TIA will go on to develop a stroke within one year and a further 5% per year after this. diagnosis is more difficult than with stroke as often all signs have resolved by the time the patient presents. Thus early specialist assessment along with appropriate radiological imaging is indicated in any patient with a possible TIA.

EARLY COMPLICATIONS

Stroke especially affecting the brain-stem or if reducing the level of consciousness can cause airway problems with airway compromise and respiratory arrest. It is therefore vital to ensure that the patient has a clear airway and is not in any respiratory distress. If the patient has a reduced level of consciousness then they are at risk of aspiration and developing further respiratory compromise.

In the acute phase post-stroke blood pressure can become labile. Hypertension is common in this phase and it is recommended that it not be treated without prior medical review. The elevated blood pressure serves to increase blood flow to ischaemic penumbra of the brain and thus helps to limit damage from the stroke. Blood sugar should be checked as soon as possible as hypoglycaemia can both mimic a stroke and worsen ischaemic neuronal damage and cause a worse prognosis.

There is a high incidence of swallowing difficulties following stroke with some studies showing an incidence of up to 50%. Those patients most at risk of dysphagia are those male, aged greater than 70 years and with clinically more severe strokes. These patients have a high risk of aspirating and developing pneumonia. If in any doubt it is better to keep the patient nil PO until they can be fully assessed by a trained person. It is important to remember that the presence or absence of a gag reflex does not correlate with the presence of a swallow disorder and possibility aspiration.

Pyrexia post-stroke can be a part of the stroke itself or due to superimposed infection especially in patients that are presenting late to hospital. Pyrexia whatever the cause leads to a worsening of prognosis and should be treated to lower body temperature to normal.

Between 5%-10% of patients develop seizures at the onset of a stroke. In any patient presenting with new onset epilepsy or status epilepticus one should be vigilant for an underlying stroke.

Deterioration in level of consciousness is an ominous sign and implies a poor prognosis. Causes include progression of the stroke and haemmorage, transformation where bleeding occurs into an ischaemic area.

NEW DEVELOPMENTS

The attitude towards stroke management is changing. There is a large move towards organised Stroke Unit Care with dedicated multi-disciplinary team looking after all stroke patients admitted to a hospital. The team consists of physiotherapist, occupational therapist, speech and language therapist, dietitian, specialised nursing and medical staff. Stroke Units lead to a reduction in death or disability with more patients being discharged home independently and less going onto long term care.

Causes of deterioration post-stroke

Neurological

Progression/completion of stroke
Extension/early reoccurrence
Haemorrhagic transformation of infarct
Cerebral oedema
Obstructive hydrocephalus
Epileptic seizures
Incorrect diagnosis
Non-neurogical
Infection
Metabolic derangement
Drugs
Hypoxia
Hypercapnia

In ischaemic stroke there is an occlusion of a cerebral artery or else a reduction of perfusion secondary to severe stenosis. This reduction in cerebral blood flow causes loss of neuranol electrical function, which becomes irreversible below a certain level of perfusion. At this level there is failure of cellular pathways leading to cellular swelling and death. New breakthrough treatments for acute stroke have concentrated on the fact that when blood flow is reduced initially there is an area of neuronal cells, the so called ischaemic penumbra where damage is reversible.

Treatments such as thrombolysis aim to restore blood flow to these areas thus limiting damage caused and minimising disability from the stroke. Unlike the situation for myocardial infarction, thrombolysis has yet to be licensed in Europe despite being available in North America since 1995. The benefits of thrombolysis are substantial for a minority of patients but it has only been of proven benefit when given within three hours of onset of symptoms. This gives a very narrow door to needle time in hospital and ideally patients need to get to hospital within one hour after the onset of stroke symptoms to benefit from therapy.

Other new treatments, which are at the trial phase at present, include neuroprotectant drugs, which protect neurones from the effects of reduced blood flow following stroke. These drugs are promising because they can only be used along with thrombolysis but they have a longer 'door to needle time.'

There is cause for guarded optimism for further improvements in stroke care in Ireland, but this will depend on a concerted effort to take the illness seriously and to treat stroke as a 'brain attack' in the same way that we deal with heart attacks. We need to develop Stroke Units in every general hospital, and to develop community rehabilitation services on the model of the very successful unit at Baggot Street Hospital in Dublin. Patients can also help themselves by joining the Volunteer Stroke Scheme, an organisation to support patients and their families after stroke.


This article appeared in the Volunteer Stroke Scheme News Letter - June 2001