Recognising Early Stroke
By: T.V. Keaveny, Vascular Surgeon
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Recognising Early Stroke By: T.V. Keaveny, Vascular Surgeon |
The full implications of the effect of stroke are best known to the patients who have suffered, their families and the medical and community services, including the voluntary groups who care for them. Stroke is the third leading cause of death in the western world. A recent article in the British Medical Journal, emphasising its frequency, pointed out that approximately one patient developed stroke every five minutes in the United Kingdom. Nearly as many patients die from stroke as from all forms of cancer combined.
Realising that the cause of stroke is preventable, the implication of these statistics is enormous. In addition there is a high mortality from stroke but the encouraging indication is that there seems to be a decline in this mortality in some countries. The reason for this decline is not clear but changes such as this deserve research to see what factors vary between countries so as to influence the incidence and mortality of stroke. It is estimated that 16% of all women are likely to die from stroke and 8% of all men. Because women tend to live longer than men, more elderly females die from stroke. If we examine a population of a million, as has been carried out in New Zealand, 1,600 will develop stroke each year. Of this 1,600 approximately half will survive. The majority of these survivors will be cared for in private accommodation and the remainder are a heavily dependent group in institutions. Six months after a stroke, two-thirds of surviving patients will be found living at home and regard themselves as independent. This independence is, of course, a product of their own efforts and the community and support care which is available.
A major complete stroke is readily recognised and forms the image that most people have when discussing stroke. This is regrettable for the reason that stroke takes many forms and it is vitally necessary to recognise early stroke and stroke in evolution. Stroke is damage to the brain as a result of impairment of blood supply. It is caused by several factors. The chief of these are:
PREVENTING STROKE
Because there is a close association between diseases of the arteries (arteriosclerosis) and heart disease, there are two aspects to prevention of stroke. One is primary prevention which means avoiding those factors which will result in damage to the blood vessels and heart. These are well known and include avoidance of smoking, suitable diet, control of blood pressure, diabetes, weight control, suitable exercise and appropriate life style. Once the disease has occurred in the arteries, other measures then come into play which are called secondary prevention. These include various medications which affect either the blood vessels or the blood itself and the best known example of this is Aspirin; and secondly, careful treatment of heart conditions, sometimes by the use of blood thinning agents (Warfarin) and meticulous control of blood pressure. Finally, there is the very important aspect of surgery, which is another form of secondary prevention of stroke.
The reason why stroke may be prevented by surgery is because a great majority of strokes are due to disease in the carotid arteries in the neck. When these become rough as a result of arteriosclerosis, changes occur which lead to the reduction in blood supply to the brain. Secondly, particles may escape from the roughened artery, travel either to the eye causing partial blindness or to the brain, causing minor stroke symptoms. These symptoms are more significant if they affect one side of the body.
For example, transient visual loss in one eye is very dramatic and usually encourages the patient to seek attention very quickly. Other symptoms are less easily appreciated as stroke manifestations. These include temporary loss of power in the hand or foot, disturbed sensation such as pins and needles in one hand or in one foot, difficulty with speech, blackout and temporary memory loss. There are other symptoms which are very troublesome, but less dangerous, and these include dizziness (vertigo), double vision, loss of balance and other more vague symptoms. Many of these are in fact associated with arthritis of the neck which is very commonly associated with carotid artery disease. These should be investigated at the same time, but are less dangerous and the treatment is different.
Disease in the carotid arteries may be diagnosed from examination when abnormal sounds or bruits will be heard. Such a bruit may also be heard in patients with no symptoms and does not always imply a serious condition. The next step in investigation requires examination by ultrasound using a Duplex scan. This is non-invasive but requires a high degree of technical skill in vascular departments or some X-ray units. If serious disease is located further investigation using angiography can be carried out as an in-patient.
SURGERY
In a proportion of patients this will ultimately lead to surgery by identifying a serious lesion in the artery. If the patient is reasonably fit medically the optimum treatment is an operation called carotid endarterecomy. This involves removing the core of the artery thereby removing the part which is the source of emboli to the brain. The outcome of the operation depends heavily on the experience of the unit in which it is performed.
In order to achieve a satisfactory prevention and reduction of stroke rate, the mortality and morbidity rate must be low and the results carefully monitored. It has been shown in significant trials in both North America and in Europe that there is great reduction in the incidence of stroke following this procedure compared with patients who are treated medically alone.
It must be understood that many patients also suffer from other forms of vascular disease, particularly heart disease, and also stretching of the main arteries, called aneurysm, particularly in the abdomen. Furthermore, many may have limitation of walking due to the interruption of the blood supply to the lower limbs. All of these conditions must be assessed at the same time.
It is obvious that patients who develop early symptoms should be thoroughly investigated in order that the cause of the possible stroke is found and also to diagnose other contributory diseases before proceeding to surgery.
The operation is discussed with the patient and relatives so that the implications are understood. Advances in diagnosis and anaesthesia have contributed to increased safety of the procedure.
The most important factor in stroke prevention is the recognition of early symptoms which indicate the possibility that a major stroke will develop. When patients develop these minor symptoms, it is estimated that stroke occurs at the rate of approximately 10% per annum. The fact that many strokes can be prevented should be a consolation and encouragement to all those who contribute to the care and management of stroke victims.