STROKE can be defined as a sudden interruption of blood flow to the brain due to blockage or rupture of the brain arteries resulting in partial or complete paralysis of one half of the body accompanied by speech disturbances and impairment of memory or level of consciousness.
Three types of stroke are commonly encountered; they are: Thrombotic, Haemorrhagic and Embolic. Both the thrombotic and the embolic involve clot formation within the arteries of the brain or from the left side of the circulation such as the heart, aorta or its main branches. In thrombotic stroke, complete occlusion of an artery within the brain occurs. In the embolic variety, blood clot formed outside the brain (e.g. in the heart, legs, etc) is carried to the brain where it blocks an artery in the brain. In the haemorrhagic stroke, tiny tears occur in worn-out blood vessels with leakage of blood into the tissue.
Thrombotic stroke is frequently heralded by brief transient neurological complaints (such as weakness in the legs or arms) in the days, weeks, or months preceding the onset of the fixed neurological damage. These brief early warnings tend to be similar. The fixed neurological disability usually develops in a step-wise fashion over a period ranging from minutes to hours (a stroke in evolution). Once the thrombosis is secure, the neurological damage stabilizes (a completed stroke).
This type of stroke in adults may occur at any time, but a disproportionately large number seem to appear at night during sleep or soon after waking. The reason for this is unknown. The clinical features, including the warning symptoms include the following: headache, transient weakness of limbs or speech, bizarre behaviour, poor memory, forgetfulness, intellectual deterioration; numbness of one half of the body, epileptic attacks, partial blindness in one eye or both, dizziness, giddy turns, double vision, hand tremors and vomiting.
When examined, in addition to the finding of partial or complete paralysis of limbs and face on one side of the body, there may be memory impairment, loss of bladder control, poor peripheral field of vision, limb tremors, lack of appreciation of skin sensation on one half of the body. The signs of the underlying predisposing factors may be found such as the signs of hypertension, diabetes or meningitis.
Embolic stroke usually occurs abruptly (seconds to minutes) and neurological disability are usually maximal at the time of onset but may be stuttering in a similar fashion to thrombotic stroke. The neurological complaints and signs may be under spread picking out parts of the body one at a time due to under spread clot dissemination. At the onset, there may be sudden loss of consciousness due to a large embolic occlusion of the arterial supply to the brain. Rapid and progressive recovery is frequently seen due to the disintegration and passage of the obstructive clot.
On physical examination, the clinical signs are similar to those found in thrombotic stroke. However, signs of the predisposing factors such as heart diseases, sickle cell disease, blood diseases and blood borne diseases should be sought.
Haemorrhagic stroke is an acute explosive phenomena. The onset is abrupt, usually occurring without warning, while the patient is active. Such activity may be physical (i.e. after a quarrel, a fight or sexual activity) or follow mental or emotional excitement (watching favourite interesting T.V. programmes) or mild (sitting on the toilet seat in the morning). Severe headache, often with nausea and vomiting, preceeds the development of the neurological signs. Patients with this type of stroke frequently present with stupor, coma and death. Recurrence of similar episodes is uncommon. Recovery is slow and variable. The overall mortality is about 50%, neurological signs are present and maximal at onset, predisposing over a fairly long period before recovery. If it does not result in death or coma, the paralysis of one half of the body is complete and dense. The other clinical signs are similar to that described under thrombotic stroke.
How common is stroke? Stroke is one of the major causes of sudden death in the Adult African. In addition, it is one of the commonest causes of paralysis in the African population. Unfortunately, only a very small percentage (less than 4%) of the adult population at risk have access to modern health facilities. The health education programme within the community is grossly in adequate and hardly reaches the target rural population where 70% of the people live. The problem is further compounded by the High illiteracy rate (about 65% of the total population) and the socio-cultural beliefs and taboos concerning the nature of this neurological disorder among our population.
Who is affected? Our information may not be very accurate due to lack of facilities for broad based, properly supervised surveillance of the disease within the African population. Most of our data came from hospital based studies and statistics derived from stroke Registries of our major hospitals. In general, males are more affected than females. The male to female ratio varies from 2:1 to 3:1. The reason for this preponderance of males in our hospital studies may be socio-cultural, since males generally receive more attention and care when they fall ill being the breadwinners within the family set up.
Africans tend to suffer from stroke at a relatively younger age than Europeans. The mean age at presentation is between 40 and 50 years. With improvement in the socio0economic standard and increase in the life-expectancy of Africans it is likely that the elderly population will die more from stroke than heart attack.
Stroke affects both the rich and the poor people. Most studies tend to emphasise that stroke commonly afflict the middle and upper social classes. It may be that rich people have easy access to modern health facilities.
Causes of Stroke: The causes of stroke are multifarious depending on age. In children and adolescents, the major causes of stroke are sickle cell disease, congenital or acquired heart diseases, meningitis, arteriovenous malformations and brain abscess or tumours. In adults the common causes include hypertension, diabetes mellitus, heart disease, blood cancers and blood borne diseases, meningitis and brain tumours. However, the major causes in 60% of adults are Hypertension and Diabetes Mellitus occurring singly or together.
Symptoms and Signs: In general, patients with stroke present at the hospital in coma or if conscious with the following: partial or complete paralysis of one side of the body – limbs an face – including disturbances of speech, memory or bladder control. Not all cases of stroke present fresh at the hospital; some come to the hospital having sustained one or more repeated strokes in previous years with distressing neurological sequelae. It is pertinent to emphasise that it is only a well trained specialist physician that can safely diagnose and distinguish between the three varieties of stroke just listed. Unfortunately, such cadre of specialist physicians are mostly found in the teaching hospitals, a few general hospitals and private clinics.
When patients with stroke are brought to the hospital, since the patients can hardly communicate verbally, the attending doctors often rely on the answers from family members, close friends and relations in order to make a good historical diagnosis. Quite often such valuable information is not forthcoming leaving an inexperienced physician frustrated and undecided about what urgent steps to take in saving the patient’s life. For instance, the attending doctor would often like to know the following facts on the patient’s case history.
- Time and date of the attack,
- What the patient was doing at the time of the stroke,
- Presence or absence of complaints e.g. headache, dizziness at onset,
- Level of consciousness during attack,
- Any previous stoke?
- History of stroke, hypertension and diabetes mellitus in the family,
- Previous medical conditions and treatment for same,
- Is the patient under treatment for hypertension, diabetes mellitus, cardiac disease or bleeding disorder?
- If female patient, contraceptive pill usage, abortions, irregular menses?
A consultant physician can determine what type of stroke or state of the “stroke process” from the above information. Two stages of stroke are commonly discernible by the time the patient presents in the hospital. The approach to the treatment of both stages are different and unless recognised a lot of harm could be done to the patient. Therefore, a few hints should be given in recognising the two stages.
Stroke in Evolution: This can be termed gradually developing stroke. Clinical disability (paresis of limbs and movement, speech memory or bladder disturbance), evolve over a variable period of a few hours or a few days.
- The paresis or disturbances of neurological function worsens as the time progresses,
- There is a time lapse (varying between hours today) between the onset complaints and the time the patient presents in the hospital. During this stage, for instance, prompt treatment with anticoagulant meditation often arrest the process of clot formation in the brain and limits the extent of neurological damage.
Completed Stroke: In this stage, the stroke process is already complete. The neurological damage has been completed and there is maximal disability at presentation. The limb or speech paralysis no longer progresses at the time the patient is being reviewed in the hospital. Anticoagulant medication is not indicated at this stage or it will cause further neurological damage.
Treatment: Facilities for investigating a stroke exist mainly in the general or teaching hospitals. Such investigations include the following: blood test, cerebrospinal fluid examination, urine examination, serum Cholesterol and blood sugars, chest x-ray, electrocardiography. Carotid angiography and computerised Axial Tomograph (Atscan), whichever is considered important and less hazardous.
All these investigations yield valuable information about cause and type of stroke and the extent of brain damage.
Treatment of a stroke patient should preferably be hospital based especially in the early stage when the patient is comatose or has complete loss of muscle power. Treatment may be medical, surgical or both. Treatment modalities are aimed at achieving near normal or complete recovery of neurological function (muscle power, speech, bladder control) such that the patient can live an independent life on his own with minimal assistance from immediate family members, relatives and friends.
In a conscious patient attention is often focussed on the following:-
– Care of the limbs
– Care of the skin
– Care of the bladder and rectum
– Regular physiotherapy exercises including mental and occupational rehabilitation.
The above measures are more conveniently done in a hospital setting with the co-operation of the patient’s family or close friends. The underlying predisposing factors are treated adequately by medical means (i.e. control of Diabetes mellitus and hypertension with relevant drugs and regular follow ups) and surgical means (use of orthopaedic appliances for limbs, neurological and cardiac operations to correct heart or brain vessel abnormalities).
Prevention: A common disease such as stroke which maims and kills both the young and adult population can only be effectively controlled when the whole population at risk have an adequate knowledge about the disease. Unfortunately, only a very small proportion of our population, especially those in medical circles know about the presentation, causes and damaging effects of stroke. Those who have such information rarely have access to the mass media. In the radio and television broadcasts, very little time is allotted to health programmes, the most time being devoted to promotion of social habits that will enhance the development of stroke in the population. The major predisposing factors such as hypertension, diabetes mellitus, obesity, cardiac or blood disorders can be prevented or adequately treated before stroke sets in by regular medical checkups and adherences to prescribed treatment.
The Federal Government has adopted the primary health care policy aiming at preventing most of the common killer diseases in our population and this policy is most welcomed. Another brilliant aspect of this policy is that it will be community based with its roots in the rural areas where majority of our people live. The cornerstone of this policy also involves health education at all levels. This education course can be done at minimal costs but the benefits of the national health programme would be immense, and would go a long way in preventing stroke in our population.