QUALITE, EQUITE ET ACCESSIBILITE TECHNOLOGIQUES
L’équité, la qualité, et l’accessibilité sont les principaux critères d’excellence des systèmes de santé proposées par l’OMS.
Ils sont loin d’être atteints, lorsque l’on transpose ces critères aux aspirations et réalités d’utilisation des technologies modernes par la communauté scientifique des pays du Sud. Le principal frein est essentiellement économique, le savoir théorique scientifique pouvant être acquis avec de moindres difficultés. En effet, la mise en application des concepts scientifiques pose de véritables problèmes à cause d’une absence d’équipement adéquat. Lorsque l’on connaît le maigre budget des laboratoires de recherche, la faiblesse des équipements des hôpitaux en Afrique et des cabinets des praticiens, il est évident qu’offrir la qualité, sur fond d’équité relève de la gageure. Ainsi, le fossé entre les pays du Nord et du Sud se creuse. Le « gap » ne cesse de s’accentuer. Cette dérive d’une partie du monde n’est pas inéluctable si l’on fait appel à l’imagination, à la créativité et la solidarité. La mobilisation des ressources financières doit se faire directement sur des projets CONCRETS. En se fondant sur une culture du résultat immédiat – car il y a urgence- la communauté scientifique doit intervenir énergiquement auprès des décideurs politiques et institutionnels afin que l’allocation des ressources se fasse vers des projets « palpables ». Que pourrait-on faire ? A quel niveau agir ?
1 – Internet. Le réseau diffuse librement, avec toutefois un coût, le savoir aux quatre coins du monde, 24h/24h. Outre l’information scientifique et la communication entre praticiens, internet permet d’apporter une assistance technique à distance, de maintenir la qualité des équipements sur le terrain. Internet demande à être étendu très rapidement, en évitant de perdre du temps et de l’argent dans des grands messes, des « sommets », sans intérêt, comme on vient de l’observer avec la récente réunion mondiale sur la société de l’information. Les rencontres sur la communication et l’intérêt des nouvelles technologies dans le développement des sciences et techniques en direction des pays pauvres, sont superfétatoires, totalement inutiles. Aider à l’installation de connexions à moindre coût pour la communauté scientifique du Sud serait une initiative salutaire.
2 – L’administration d’un grand nombre des pays du Nord impose un renouvellement à intervalle régulier des appareils médicaux des établissements hospitaliers, alors qu’ils fonctionnent encore et peuvent rendre des services. Une convention avec certains établissements pourrait réorienter ces machines, en parfait état et qui fonctionnent en direction des pays du Sud.
3 -Les entreprises du Nord. Le coût des appareils « up to date » est et sera pendant longtemps encore inaccessible à la majorité des scientifiques, et des médecins en Afrique. Certaines options proposées sont d’un intérêt relatif voire non fondées sur des preuves scientifiques. Il importe de concevoir, et de développer des appareils disposant de fonctions fondamentales, « basiques », validées scientifiquement, solides, fiables dénués de sophistications sans intérêt confinant au gadget qui augmentent les prix de vente. L’industrie automobile s’est emparée de ce constat et cible le marché des pays en développement ou émergents sous un angle réaliste. Ainsi, Renault (France) propose actuellement des voitures fiables aux pays du Sud pour un prix de 8 000 euros.
4 – Les entreprises du Sud. Les firmes du Sud peuvent produire des matériels fiables, répondant aux exigences scientifiques à des prix défiant toute concurrence. Ainsi, des valves de dérivations ventriculo-péritonéales conçues sur des bases scientifiques prouvées, produites par des entreprises indiennes sont disponibles à 30 euros au lieu de 1000 euros, prix des modèles commercialisés en Europe et USA par les « majors ».
5 – Les sociétés savantes. L’exemple de la World Federation of Neurosurgical Societies (WFNS) est intéressante et pourrait être copié. En effet, grâce à une collaboration avec une grande société internationale d’instruments médicaux, des sets neurochirurgicaux et des microscopes opératoires de qualité sont vendus à des prix accessibles aux hôpitaux du Sud.
Le débat est ouvert. Mais l’action doit demeurer la règle directrice.
QUALITY, EQUITY AND TECHNOLOGICAL ACCESSIBILITY
Equity, quality and accessibility are the main excellent performance criteria of health systems, proposed by the WHO.
These criteria are far from being met, especially in the context of the aspirations and realities in the use of modern technologies by the scientific communities of the countries of the southern hemisphere. The main limiting factor is economic, as theoretical scientific knowledge can be acquired with fewer difficulties. In fact, the absence of appropriate equipment is a serious problem to the application of scientific concepts. When we consider the meager budgets of research laboratories, the limited equipment of African hospitals and medical cabinets, it is clear that the offer of quality care within a background of equity remains a big challenge. Thus, the gap between the countries of the northern hemisphere and those of the southern hemisphere is widening. This detachment of a part of the world is not unavoidable if we employ imagination, creativity and solidarity. The mobilization of financial resources should be done on CONCRETE PROJECTS. Building on a culture of immediate results – there is an emergency – the scientific community should insist on obtaining financial resources from political and institutional leaders for “palpable” projects. What can we do? At what level should we act?
1 – Internet. The network is diffusing knowledge freely throughout the world, 24 hours / day. There is however a cost to pay. Besides scientific information and communication between practitioners, the internet allows for technical assistance to be given at a distance and to maintain the quality of equipment in the field. The Internet needs to be extended very rapidly, while avoiding waste of time and money in big rallies and « summits » which do not have any effect as was recently observed with the world meeting on society and information. Big meetings on communication and the interest in new technologies in the development of the sciences and techniques for poor countries constitute a completely useless additional load. Assistance to establish low-cost connections for the scientific communities of the southern hemisphere would save the situation.
2 – The Administrations of a large number of countries of the northern hemisphere have the discipline of regularly renewing hospital medical equipment even when they are still in good condition. A convention with some institutions could re-orient these machines in good functional state to countries of the southern hemisphere.
3 – The entreprises of the northern hemisphere. The cost of the latest machines is and will remain for a long time inaccessible to most scientists and physicians in Africa. Some of the proposed options are of relatively low interest or even lack a scientific basis. It is important to conceive and develop reliable, robust and scientifically validated equipment with basic functions, avoiding useless sophistications that simply blow up the selling price of these ‘gadgets’. The automobile industry has seized the opportunity of this observation and aims at the market in the developing or emerging countries from a realistic point of view. Thus, Renault (France) now proposes reliable cars to countries of the southern hemisphere for 8000 euros.
4 – The enterprises of the southern hemispheres. The firms of the southern hemisphere can produce reliable pieces of equipment that respect scientific norms, at unchallengeable costs. Thus, ventriculo-peritoneal shunt valves conceived on proven scientific basis and produced by Indian companies, are available for 30 euros instead of 1000 euros, the price of models commercialised in Europe and the USA by the « major » companies.
5 – Scientific Societies. Through a collaboration between the World Federation of Neurosurgical Societies and an important international medical instruments company, neurosurgical kits and high quality operating microscopes are sold at prices that are accessible to hospitals of the southern hemisphere. This very interesting example can be copied
The discussion is open but action should be the leading rule.
HOW CAN WE IMPROVE THE MANAGEMENT OF STROKE IN NIGERIA, AFRICA?
Stroke is a significant economic, social and medical problem all over the world.
This article discusses recent developments in stroke management worldwide. We reviewed and highlighted published clinical guidelines from several countries. The current thoughts on stroke care are discussed and summarized in concise and unambiguous terms. Limitation to optimal management in developing countries as well as areas requiring development and research are highlighted. It should be possible to utilize this in stimulating the development of management strategies for stroke, customized to the unique health structure in Nigeria.
The management of stroke in Nigeria is suboptimal as there are significant deficiencies in the provision of diagnostic, treatment, rehabilitation and support services. The limited resources, manpower shortage, lack of organized stroke unit, neuro-imaging facilities, ambulance services, education of patients and general practitioners as well as impracticable use of thrombolytics are contributory. Training of stroke experts in collaboration with experts in the developed world with provision of neuro-imaging facilities would improve the outlook of stroke management in Nigeria.
The focus in Nigeria must be on preventive strategies and ways to harness local resources in the acute treatment of stroke patients. Health education of the community with emphasis on control of the predisposing factors would reduce the burden of stroke in the country. Risk factor management should begin in childhood, with emphasis on exercise, nutrition, weight and blood sugar control, avoidance of tobacco and excessive alcohol, as well as effective treatment of hypertension and hyperlipidaemia.
Keywords : Africa, Accident vasculaire cérébral, Stroke, Nigeria
Stroke is the acute and dramatic onset of focal or global neurological deficit, which is most often caused by interruption of the blood supply to the brain or indeed hemorrhage into brain tissue lasting more than one hour or leading to death 86,95 . The incidence of stroke is increasing worldwide, in part mostly due to the increasing aging population 95,96,50. Stroke is now the third leading cause of death in most industrialized countries, among adults aged 65 years or more11. The estimated incidence is about 150-200 cases per 100,000 of the population 53, 72, 77, 78, 89, 93. though there is a wide range of variation between areas; Japan and Finland experience the highest age-adjusted rates.16, 42, 47. The age-adjusted incidence rate of 145.6/100,000 population in Kuwait is very low due to the young average age of the Kuwaiti population1.
Stroke causes significant disability and death in many countries and places a huge financial burden on health services. This is estimated at £2.318 billion costs to the National Health Service in the United Kingdom for 1995-6 alone 11. In America, approximately 500,000 strokes occur each year. The direct cost of providing care for stroke victims in 1993 was estimated to be USD17 billion, with an additional USD13 billion in indirect costs attributable to lost earnings due to stroke-related mortality and morbidity 88.
In Nigeria, the impact on the local economy and the financial burden of stroke in Nigeria has not been estimated. The size of the problem appears to be underestimated by the government as no actual publications or statements exist acknowledging the impact of stroke on the health of the nation. A more up to date and current information on the magnitude of the stroke problem in Nigeria is needed 66, 91. Majority of the stroke costs are borne by individual families. There is the need to evaluate the percentage of patients dependent on carers and the yearly expenditure on hospital stay, home rehabilitation as well as information on the loss of income for the patient and carers. The information required for more rational predictions of the burden of stroke in the community are as follows: 1) Number of new stroke cases per year (incidence), 2) Total number of existing stroke patients (prevalence), 3) Number of recurrent stroke, 4) Morbidity and mortality data.
EPIDEMIOLOGY OF STROKE IN NIGERIA
The actual incidence and prevalence of stroke have not been established in Nigeria. Previous reports detailed an increasing incidence but as these were hospital-based studies, they could be inaccurate and probably represent the tip of the iceberg (35, 51, 66, 69). The frequencies in hospital populations varied from 0.9% to 4.0% and stroke accounted for 0.5% to 45% of neurological admissions 69. At the Lagos University teaching Hospital, Stroke was the second commonest cause of neurological admissions and constituted 3.7% of all medical emergencies. At the Ogun State University Teaching Hospital (OSUTH), Sagamu, it accounted for 8.7% of medical admissions and was the third commonest cause of medical admissions. At the University College Hospital, Ibadan, and OSUTH, sagamu, stroke accounted for 4.6% and 17% of medical deaths respectively compared to 7.7% of all deaths at LUTH emergency(64). This therefore appears to be a huge problem in African Nigerians.
The population of Nigeria exceeds 126 million people. If we assume an average stroke incidence of 116 per 100,000 of the population in Nigeria, then 147,000 people suffer a stroke in Nigeria yearly. Using figures from Sagamu, Nigeria, it can be estimated that roughly 34% (n = 49,980) will die within a month and 60% (n=56,700) within six months(65).
THE MAJOR STROKE TYPES
There are 3 main types and over 100 underlying causes of stroke.
– Ischemic stroke or cerebral infarction (CI):
In CI, there is interruption of the flow of blood to part of the brain (17). This could be thrombotic, embolic or due to vasospasm, and the mechanical obstruction leads to ischemia of the affected area of brain tissue. Emboli can originate from the heart or the arteries in the neck. Thrombosis of intracranial or extracranial vessels is a major cause of cerebral infarction. Modifiable risk factors are hypertension, diabetes mellitus and cardiac diseases.
– Subarachnoid haemorrhage (SAH)
SAH is a type of stroke in which bleeding occurs in the Subarachnoid space alone or in conjunction with bleeding elsewhere in the central nervous system. Primary SAH is often due to the rupture of an intracranial aneurysm while secondary SAH is most commonly due to trauma. The major risk factors for SAH are increasing age, female gender and smoking (27, 39, 43, 45, 57, 92).
– Intracerebral haemorrhage (ICH)
ICH is a type of stroke in which the rupture of an intracranial blood vessel leads to the loss of blood into the brain tissue. It can be caused by a variety of conditions such as hypertension, arteriovenous malformation, intracranial aneurysms, blood dyscrasias, anticoagulation, chronic alcoholism, vasculitis and possibly tumors 80. The main cause of ICH is hypertension with frequency as high as 72-81% (31, 62).
Cerebral ischemia comprises over 80% of all strokes, with strokes caused by ICH occurring in 10-15% and SAH making up the rest (5-10%).(10, 16, 22, 49, 52, 58, 82). The percentages are highly variable in different communities and changing patterns have been reported in several communities including Nigeria (12,16). According to a clinical report from Ibadan, Nigeria, cerebral ischaemia (CI) occurred in 48% of patients, Intracerebral haemorrhage (ICH) in 15.7% and Subarachnoid haemorrhage (SAH) in 11.3%. The stroke type was undiagnosed in 24.2% (70). Clinical diagnosis is fraught with danger and a high degree of misdiagnosis has been previously highlighted (5, 51, 64, 66). There was confusion of stroke with surgically treatable conditions such as brain abscess, glioma and subdural haematoma in 8.6-13.5% of cases (35, 51, 66, 69).
HOW CAN WE IMPROVE THE MANAGEMENT OF PATIENTS WITH STROKE ?
Stroke is no longer an untreatable condition (24). The real challenge of stroke therapy at the outset of this millennium is how to translate basic pathophysiologic evidence of ischemic neuronal injury into novel neuroprotective therapies either independently or combined with thrombolysis (60). The management of stroke is changing rapidly as new ideas appear for acute treatment, rehabilitation and secondary prevention (24). Stroke care has therefore become a specialized field, requiring input from physicians interested in stroke, as well as a multidisciplinary rehabilitation team (3).
The care of patients in Nigeria must focus on preventive strategies and ways to harness local resources in the acute treatment of stroke patients. Rational treatment requires individual causes of stroke to be identified early and treatment targeted at the mechanism (33).
What follows now is an analysis of stroke guidelines from several different countries.(3, 4, 7, 8, 13-15, 28, 30, 32, 34, 38, 40, 41, 63, 71, 84, 85, 87). This has been organized into 4 main targets areas; 1) Population strategy in stroke care, 2) The role of the physician in preventive care, 3) Managing the acute stroke patient and 4) The place of rehabilitation and prevention of recurrence. We also evaluate strategies to enlist the support of politicians and the general public in stroke awareness (3, 11, 25, 63, 67, 73).
(1): Population strategy
Public awareness programs are important
Previously, a patient cannot be considered to have had a stroke until at least 24 hours have elapsed. This leads to patient apathy and physician inactivity for such a long time! It is important to emphasize that defining stroke in terms of time (24 hours) is no longer satisfactory (33). ‘Brain’ attack’ is a term used to describe the acute presentation of stroke which emphasizes the need for urgent action (33).
Stroke evaluation must be performed within hours as delays lead to loss of brain tissue. Studies have shown that delays in presentation are caused mostly by lack of awareness of stroke (84). All patients within the age range and with a high stroke risk should know the symptoms of stroke. The need to present early for evaluation, treatment and prevention of further attacks must be discussed at various levels. Information about stroke should be made widely available to the public (67). The local press, celebrities and television personalities should be educated on the risks of stroke and the importance of wide public awareness. Stroke issues should be introduced in schools, churches, mosques, plays on television, in the theater and brought to national attention. Health talks as well as the use of posters and radio jingles would assist in re-education of relatives of stroke patients and the community at large.
Life style modification is a key move
High blood pressure and high blood cholesterol are closely related to excessive consumption of fatty, sugary and salty foods. They become an even more lethal combination when combined with tobacco and excessive alcohol consumption. Cigarette smoking should be avoided by all and especially by patients following a stroke or TIA (14, 15). Excessive alcohol should also be eliminated. Eating fruits and vegetables can help prevent cardiovascular diseases. Physical inactivity causes about 15% of diabetes and heart disease. The American Heart Association recommends 30-60 minutes of exercise 3-4 times per week 7.
Reduction of salt in food and drink
Reduction of salt intake is an important message for the population at risk of a stroke. Salt reduction leads to reduction in high blood pressure and risk of stroke (37, 59, 74).
(2): Doctors’ strategy for managing risk factors
Stroke study groups and development of local guidelines
We need to organize into stroke study groups and produce guidelines to assist physicians at different health care levels in stroke care. The purpose of stroke study groups is to increase the capacity for all hospitals to treat stroke patients according to standards of care, recognizing that levels of involvement will vary according to the resources of hospitals and systems (3). The major aim of clinical guidelines is to assist clinicians in producing local protocols for the prevention, diagnosis and management of stroke (3). This leads to improved management of risk factors and improved training of junior doctors. Further, guidelines assist in developing methods for implementation and audit of practice.
Physicians must identify patients at risk
The key must be to evaluate patients from the 4th decade for their stroke risk. This risk assessment include taking a good history of risk factors, a thorough clinical examination and simple tests such as measurement of BP, pulse (ECG if concerned), and cholesterol level, level of C-reactive protein (CRP) and calculate the body mass index. Currently, research suggests that CRP levels in apparently normal individuals may prove to be a better indicator of stroke and heart attack risk than the level of cholesterol 29. Body mass index should be between 18.5-24.9 in healthy individuals. An individual patients’ percentage risk of stroke can be calculated online via the website of the American Heart Association (http://www.americanheart.org/presenter.jhtml?identifier=3003500).
Identifying patients with hypertension and diabetes.
Age, gender and heredity are non-modifiable risks of stroke, and they should serve as risk markers to alert the clinician as to patients at risk (7). Undiagnosed hypertension and diabetes remain significant problems in many communities (66, 90). This is partly because of ignorance and lack of funds to afford the cost of medical screening. Hypertension is the single most important cause of stroke and the one, which is eminently reducible by treatment (90, 97). It has been estimated that between 52-70% of stroke patients have hypertension (35, 69, 68). Up to 60% of patients have undiagnosed high blood pressure (BP) prior to presentation (6, 90). Reduction in both systolic and diastolic pressures substantially reduces stroke risk (7, 14, 15, 37, 63, 74). The recent British Hypertension Society guidelines recommend a target blood pressure of 140/85 mmHg 75. Rodgers et al. deduced that each 5mmHg reduction in diastolic pressure reduced stroke risk by 34%, and each 10mmHg reduction of systolic pressure reduced stroke risk by 28%. It is the duty of every clinician or nurse to at least check the BP of all adults they are reviewing for any health problem (66).
Management of hypertension
Treating hypertension with drugs is the most cost-effective way to reduce this important risk factor for cardiovascular disease and stroke (87). Population attributable risks (or fractions) indicated that up to 22% of premature all-cause, and 45% of stroke mortality could be reduced by appropriate detection and treatment. It is, however, important to determine absolute risk, and thereby estimate indication for drug treatment, in order to maintain a cost-effective drug treatment. The elderly patient (most especially) should be treated starting in most cases with a simple Thiazide diuretic (87).
One crucial problem is the lack of control of BP for many patients despite medications. In Nigeria, unavailability of essential drugs, cost and sometimes fake medications are also huge problems that require concerted efforts from the government.
Diabetes is a modifiable risk factor for stroke
In view of the high prevalence of undiagnosed diabetes among stroke patients and the increased morbidity and mortality associated with diabetes mellitus, screening for diabetes is recommended especially in those with ischaemic stroke (58, 56). Diabetics should avoid refined simple sugars and excessive weight gain. Care of the feet and prompt treatment of infections should also be emphasised
Management of atrial fibrillation
The detection of atrial fibrillation and its proper treatment are essential in prevention of embolic strokes (40, 46, 71, 94). Patients suitable for anticoagulation should be treated (14, 15, 63). Cardiac medications for the control of abnormal rates may also be of value.
Treatment of hyperlipidaemia with statins is essential.
Risk factor management should be part of general health care and should begin in childhood, with emphasis on nutrition, exercise, weight control, and avoidance of tobacco. Health screening and early treatment of hypercholesterolemia has decreased the incidence of stroke and heart disease (44). Clinical trials in the 1990s using HMG-CoA reductase inhibitors (statins) showed that cholesterol-lowering treatment significantly reduces cardiovascular events including strokes in the primary and secondary prevention of myocardial infarction (MI) (9). After these observations, it is now generally accepted that lipid-lowering treatment should be considered in all stroke patients with a history of CHD/MI (9). The anti-inflammatory effect of statins and the stabilization of atherosclerotic plaque are additional benefits
Treatment of transient ischemic attacks
It is important to recognize and diagnose a patient with TIA. Confusion, blurring of vision, speech impairment, difficulty walking and weakness of an arm or a leg are possible pointers to impending major stroke. TIA could be caused by cardioemboli or from stenosis of the carotid arteries in the neck. In areas without access to Doppler Ultrasound, MR or CT, as applicable to most medical centers in Nigeria, some clinical parameters may indicate possible carotid stenosis. In one study, stepwise logistic regression showed that there were significant positive associations between severe carotid stenosis and an ipsilateral bruit, diabetes mellitus, and previous TIA 61. The strategy with the highest sensitivity (99%) was to use one or more of the four features, but specificity was only 22%.61. When access to carotid imaging is severely limited as the case in many areas in Nigeria, simple clinical features may be of some use, but access to carotid imaging should be improved.
Carotid endarterectomy is a safe preventive procedure
Severe narrowing (or stenosis) of the carotid artery in the neck is an important cause of ischemic stroke. Carotid endarterectomy (CEA) is the gold standard for the management of carotid artery disease (CAD) and the appropriateness of CEA for symptomatic and asymptomatic patients has emerged from 7 randomized trials (2, 23). Carotid endarterectomy is a safe and effective way of reducing the risk of stroke in patients with TIA (33). It is also helpful in patients with amaurosis fugax, and may benefit selected patients with acute stroke or those with asymptomatic but hemodynamically. significant stenosis (83).
(3): Treatment of first ever stroke needs to be expedient
Acute stroke treatment aims to preserve the ischaemic penumbra, protect neurons against further ischaemia and enhance brain plasticity to maximise recovery. There is a strong evidence base supporting the routine use of aspirin, but not heparin, in acute ischaemic stroke. There is also convincing evidence supporting intravenous thrombolysis using recombinant tissue plasminogen activator in selected patients within 3 hours of stroke onset.(4, 7, 8, 14, 30, 63, 71, 79, 84, 81). Although, its use in Nigeria is not feasible because of late presentation and lack of neuro-imaging facilities. Neuroprotective drugs have proved disappointing and active neuroprotection in acute stroke should include control of blood pressure within certain limits, antipyretic therapy, maintenance of blood glucose, early feeding and fluid replacement 33.
Admission to a dedicated stroke unit’ is important
To enable patients to benefit from the early active approach outlined in the article, the following are needed: the development of acute stroke units; affordable imaging facilities; and education of patients, general practitioners and the ambulance services. There is good evidence that the best way to enhance recovery from stroke is to admit the patient to a stroke unit (33, 36, 38, 73). Treatment in a stroke unit raises the proportion of stroke patients who are able to live at home, improves functional outcome, reduces the need for institutional care, and brings down mortality 18, 36.
Clinical assessment should be thorough
A full medical assessment should be undertaken to define the nature of the stroke event. Is it a stroke or a TIA? Is it ischemic or haemorrhagic ? What part of the brain is affected ? What specific problems do the patients have ? What other medical problems coexist and need to be managed ? And finally, what facilities are available for the care of the patient. The use of the WHO criteria is thought to be better than the Siriraj stroke tool in clinical classification of stroke subtypes 65.
Cranial imaging is essential
Investigations that are important should be agreed locally. Many accept that a CT scan is mandatory within 48 hours of a stroke event. A cranial CT scan is important to accurately diagnose CI, ICH or SAH. The differentiation of an ICH from a SAH is not always possible on clinical grounds alone and indeed they often coexist on CT scan. Clinical evaluation without CT scan is practiced in many areas in Nigeria. This is due to shortage of imaging facilities and cost. However, increase in referral for CT scans may bring down the costs for each individual patient and may stimulate the establishment of more facilities in the private sector. The need for such critical investigations must be stressed to local community leaders, councilors and local business entrepreneurs.
Immediate management can save lives
There is not enough evidence reliably to evaluate the effect of altering BP on outcome after acute stroke. However, high BP should not normally be lowered in the acute phase as the stroke may worsen. Stroke-in-progression occurs in about 30% of patients with acute stroke and negatively affects the prognosis and mortality. The underlying causes are thought to be clot propagation, cerebral haemorrhage, oedema or decrease in BP.
Many advocate withholding antihypertensive therapy during the acute phase of focal cerebral ischaemia. The main idea is that, to assure sufficient collateral flow to the damaged part of the brain, a high perfusion pressure must be maintained. Routine use of drugs such as steroids, plasma volume expanders and streptokinase are of unproven benefit and should be discouraged.
Management of raised intracranial pressure
First, maintenance of respiration and an adequate airway are of prime concern. Adequate oxygenation of the brain will prevent or ameliorate secondary ischemic insults. Sedation with ventilation, if necessary, mannitol and diuretics are useful in controlling raised intracranial pressure (20). Surgical hemicraniectomy should be considered in patients with malignant cerebral oedema (19, 20, 33, 54). Hemicraniectomy appears most promising as a method of avoiding death from brain compression, but the optimum timing and manner of patient selection vital (54, 60). Urgent neurosurgical care must be made available to selected patients such as those with large cerebellar infarcts, severe brain oedema and patients with SAH or ICH. In this regard, there should be close communication and early discussions with the neurosurgeon in patients with depressed level of consciousness. There is an important role for the neurosurgeon in acute stroke management in patients with CI, SAH or ICH. However, in Nigeria, the role of neurosurgeons in the management of stroke is minimal. This is partly because majority of our patients with stroke have involvement of the deep penetrating end arteries consequent of lipohyalinosis and development of Charcot-Bouchard aneurysms in long standing hypertensive .
Swallowing assessment should be undertaken as part of the initial evaluation of stroke patients. Dysphagia leads to aspiration pneumonia and complicates recovery. It is however unclear how dysphagic patients should be fed and treated after acute stroke. Further research is required to assess how and when patients are fed, and the effect of swallowing or drug therapy on dysphagia (26). Percutaneous Endoscopic Gastroscopic feeding may improve outcome and nutrition as compared with Naso Gastric Tube feeding (26).
Thrombolysis may be a problem in Nigeria
The use of thrombolytic therapy represents one of many recent developments in the management of acute ischemic stroke. The development of stroke teams and protocols has been driven by these new demands for an urgent response to ischemic stroke. The short time window of 3 hours for therapy with intravenous recombinant tissue plasminogen activator requires efficient evaluation and treatment of stroke patients and also necessitates a rigorous approach to blood pressure management, electrolytes, fluids, and temperature. At the present time, thrombolysis appears to be impractical in Nigeria because of time delay and scarcity of neuro-imaging facilities.
Patients on anticoagulant therapy demand urgent correction of the coagulation defects. Aspirin should be discontinued in patients with haemorrhagic stroke.
(4): Prevention of stroke recurrence is crucial
Transient ischemic attacks are associated with a 30 to 35 percent risk of stroke within five years of the initial episode. Every patient who has experienced a noncardioembolic stroke or TIA should be started on an antiplatelet agent. Aspirin is also the recognized treatment for acute ischaemic stroke (ICH having been excluded), and can be continued for secondary prevention (24, 33). It should be started as soon as possible and within 48 hours (40, 71, 46, 94). Aspirin dose as low as 25mg per day is effective in stroke prevention. The combination of Aspirin and extended release Dipyridamole 200mg is more effective than Aspirin alone.
Long-term oral anticoagulation should be prescribed for patients with atrial fibrillation who have suffered a recent stroke. Biological follow-up is based on control of the international normalized ratio (INR) 55. The target INR should be 2.5. Clinical and biological follow-up is necessary for patients on anticoagulants; minor bleeding complications may be the prelude to major haemorrhage 55. Control of hypertension, hyperlipidaemia and cessation of smoking are paramount and should be encouraged following the acute event.
Rehabilitation is a key step in management
This is of value in returning the patient to as close as possible to the pre-morbid level. It should be started early and be patient centred. Relatives need to be involved and taught to carry out certain procedures as necessary. We also need to assist in lifting the phobias and stigma surrounding the disabled stroke patient.
Overall, the management of stroke patients in Nigeria is sub-optimal. Stroke units are not yet developed. Neuro-imaging centers are very few and assess limited by cost and distance. Lack of facilities to monitor coagulation profiles limits the use of anti-coagulants in cardioembolic stroke in most centers in the rural areas. Most patients settle for intravenous infusion of hypertonic / isotonic infusion, medical decompression with steroid or mannitol, use of free radical scavengers, folate supplement, statins, anti-platelets and antihypertensives when indicated.
A significant proportion is seen by non-Neurologist and general practitioners who inadvertently bring down the blood pressure and compromise cerebral perfusion with its attendant poorer prognosis. There are very few neurologists, and fewer neurosurgeons, in Nigeria (membership register of the Nigerian Society of neurological Sciences) with a projected population ratio of 1:10 million population. Furthermore, multidisciplinary rehabilitation team management is difficult because of dearth of paramedical staff, physiotherapists, occupational therapists and stroke nurses.
What do our patients deserve?
Our patients deserve timely access to quality services appropriate to their needs. There are significant deficiencies in the provision of services such as diagnostic, treatment, rehabilitation and support services. Patients and their care givers want to be looked after by knowledgeable staffs that understand the full range of their needs. The diagnosis and treatment should be explained to patients and relatives by competent staff. There should be provision for regular communication and sharing of information should be encouraged between staff and patients and their relatives through constant health talks, radio jingles and use of flyers. Patients need to be closely involved in development of local services and lobbying of government officials for assistance.
No one person can claim to understand the full requirements of the patient and multidisciplinary care is of importance. Medical personnel should seek information and advice from colleagues and other staff without prejudice.
RESEARCH AND FURTHER STUDIES
Knowledge of stroke and stroke risk factors is generally low in many communities (76). The level of awareness of the Nigerian public need to be evaluated and more tests applied for continuing learning. Enduring stroke registers need to be established in defined populations in the country. This will provide a firm basis for future statistical analysis and help to define the heterogeneity of stroke. The value of such a register has been highlighted previously (22, 48, 66, 86, 97). Critical information on all aspects of stroke care is also lacking and needs to be updated. Collaboration with experts from resource-rich nations with experts in Nigeria will be of tremendous benefit in generating much needed data on the extent of cardiovascular and cerebrovascular diseases in the country. This is particularly important when attempting to validate any developed guidelines (97).
The most important strategy for stroke treatment is modification of risk factors. Effective treatment of hypertension, control of blood sugar, treatment of hyperlipidaemia, and exercise are undoubtedly effective but underused (36).
RE – APPRAISAL OF RISK FACTORS FOR STROKE IN NIGERIAN AFRICANS – A PROSPECTIVE CASE – CONTROL STUDY
The existing evidence strongly implies that good care of patients with stroke starts with organization of the entire stroke chain; from the prehospital scene, through the emergency room, to the stroke unit. Most patients need immediate evaluation and the seriousness of the condition recognized (3). Without structured stroke services no pharmacological or intervening therapy is likely to improve the outcome of the patient with a stroke (60).
Thrombolysis apart, our patients deserve better care from the moment they have their first TIA. Patients with mild stroke should be managed in a specialist stroke/TIA clinic. Those needing admission should be managed on an acute stroke unit for stabilization, CT scanning and other investigation, and diagnosis, and then referred, if possible, to a specialist stroke rehabilitation unit. Attention should be paid to risk factors to prevent recurrence. This is the ideal that requires modification for the situation in Nigeria.
Stroke is one of the major challenges facing medicine with a frightening statistics of being the second leading cause of death and the leading cause of physical disability worldwide. Identification and management of risk factors remains the key to reducing morbidity and mortality from stroke.
Eighty patients with clinical presentation of stroke were recruited consecutively from the Emergency Departments of the University Teaching Hospital and Specialist Hospital – both situated in Benin City, Nigeria. The patients were followed up for a two year period (June 2000 – June 2002) and risk factors analysis was done on all patients. The patients were compared with eighty age and sex matched subjects without stroke (controls).
Hypertension remained the dominant risk factor with an odds ratio of 2.68 (95% CI 1.29 – 5.59). Diabetes mellitus independently conferred a risk of 3.23 (95% CI 1.09 – 5.71) and in combination with hypertension enhanced stroke risk (odds ratio 7.21; 95% CI 5.79 – 13.27; p<0.05).
Cigarette smoking, obesity, atrial fibrillation and physical inactivity significantly increased stroke risk (p<0.05). On the other hand, dietary habits, alcohol consumption and serum cholesterol were not important risk factors in Nigerians.
This study emphasized the significance of optimal blood pressure and glycemic control in stroke prevention. The message for all is to exercise, maintain a healthy weight, avoid smoking and monitor blood pressure and glucose levels regularly.
En étant la deuxième cause de mortalité et l’une des causes majeures de handicap dans le monde entier, les accidents vasculaires cérébraux (AVC) représentent un défit médical majeur. L‘identification et la maîtrise des facteurs de risque restent la clé de la réduction de la mortalité et de la morbidité.
Materiel et Methode
80 patients présentant des signes vasculaires cérébraux ont été recrutés consécutivement au niveau du service des urgences et du service de neurologie du centre hospitalier universitaire ; Benin (Nigeria). Les patients ont été suivis pendant une période de deux ans (juin 2000 – juin 2002) et les facteurs de risque ont été analysés chez tous les patients . Les patients ont été comparés avec un groupe témoin de 80 personnes sains, sans notion d’AVC.
L’hypertension artérielle reste le facteur dominant avec un odds ratio de 2,68 (95 % CI 1,29 – 5,59) le diabète sucré confère indépendamment un risque de 3,23 (95 % CI 1,09 – 5.71) et en combination avec l’hypertension artérielle le risque de survenu d’un AVC est plus élevé (odds ratio 7,21 ; 95% CI 5,79 – 13,27 ; P inférieur à 0,05, la consommation de cigarette, l’obésité, la fibrillation auriculaire et l’inactivité physique augmentent de manière significative le risque d’AVC (P inférieur à 0,05) Par ailleurs, les habitudes diététiques, la consommation d’alcool et l’hypercholestérolémie n’était pas un facteur de risque important.
Cette étude insiste sur la nécessité de contrôler la pression artérielle et la glycémie dans le cadre de la prévention des AVC. Il importe dans cette optique de veiller également au poids, à éviter la consommation de tabac avec pratique d’un exercice physique. La pression artérielle et la glycémie devront être contrôlés régulièrement.
Keywords: Africa, Nigeria, risk factor, stroke, Afrique, Nigeria, facteur de risque, accidents cardio-vasculaires cerebraux
Cerebro-vascular accident or stroke has remained a major challenge to physicians worldwide. It is still the third leading cause of death in the United States[4,9] and the leading cause of serious long – term disability[7,14]. It is estimated that 700,000 American residents experience a new or recurrent stroke, with an estimated 500,000 having their first stroke. This disease was believed to be rare in the black Africans five decades ago, but is now as common in developing countries such as Nigeria and other African countries as in the Western world. Recently, there are reports indicating that stroke is the leading cause of neurological admissions in most tertiary hospitals in Nigeria, taking over from central nervous system infections reported in earlier studies[29,32]. This is an indication that it is assuming a significant dimension among the non-communicable diseases in African countries, including Nigeria. It accounted for 0.92 – 4% of hospital admissions and 2.83 to 4.52% of total deaths[28,33]. Though the actual incidence of stroke in Nigeria has not been established but reports indicate that the incidence is likely to be high and the mortality increasing, as in other African countries[13,27].
Stroke accounted for 10 – 12 percent of all deaths in industrialized countries and about 88% of the deaths attributed to stroke are among people over 65 years. In 1999, a total of 167,000 deaths from stroke occurred in the United States; of these approximately half occurred out of hospital. Though it appeared death rates from stroke have fallen dramatically in recent decades in most industrialized nations, with Japan experiencing the most precipitous fall. Yet these trends in stroke mortality cannot be fully explained but they are not unlikely to be related to the changing risk factor levels over time.
The modification and treatment of risk factors such as hypertension, diabetes mellitus, hyperlipidemia and atrial fibrillation directly influence incidence and indirectly affect case fatality of stroke, as the natural history of the disease is altered. The identification and understanding of the magnitude of these risk factors will go a long way in stroke prevention, notwithstanding reports of lack of risk factors in young Africans.
In Nigeria, however, there are very few reports that have adequately addressed this issue in recent times. Studies in Nigerian Africans have shown that hypertension is the dominant risk factor for stroke8,16,26,33-35 and its control has been associated with reduction in risk in other populations[10,44]. Diabetes mellitus[33,35] and homozygous sickle cell disease (in children only)[1,16] have also been reported as major risk factors, though the latter has not been shown to be important in more recent reports.
Other identifiable risk factors reported in most western countries have not been investigated extensively among Nigerians, though some reports have mentioned obesity, anemia, dehydration, infections (including HIV infection[16,24]), under-nutrition and congestive heart failure. Smoking has not been reported as a major risk factor for stroke in Nigerians.
This analytical case – control study was designed to re-evaluate the risk factors for stroke in Nigerians with the objective of determining their significance and relative magnitude, and thus improving our understanding of the roles of these factors in our stroke patients. This will, in turn, aid in prevention of this disease.
Eighty consecutive patients with clinical diagnosis of stroke and above 14 years of age were recruited from the Emergency departments of the University Teaching Hospital and State Specialist Hospital in Benin City, Nigeria and followed up between June 2000 and June 2002. Eighty consecutive age- and sex- matched subjects without clinical evidence of stroke were recruited within the study period as controls. Informed consent was sought from subjects and/or relatives when necessary, and approval was received from the Hospital Ethics committees.
All newly admitted cases of stroke were seen, interviewed, clinically evaluated and investigated using a questionnaire and management plan by authors. The questionnaire was designed to obtain information on demographic data (age, gender marital status), social factors (level of education, occupation, income, smoking, alcohol consumption, physical exercise and dietary habits), clinical factors (blood pressure; past history of hypertension, stroke, and diabetes mellitus; family history of hypertension, diabetes mellitus and stroke, presence of heart disease, obesity (body mass index (BMI) calculated and waist circumference measured), carotid artery bruit, cardiomegaly, cardiac murmurs and fundoscopic changes; neurological status (level of consciousness, pattern of deficit) and investigation outcomes (fasting blood sugar, serum cholesterol, hemoglobin levels, hemoglobin genotype, erythrocyte sedimentation rate and CT brain scans).
Controls were recruited from the general outpatient department and these were patients without stroke or past history of stroke. They were similarly interviewed, clinically assessed and investigated. Benin City is a cosmopolitan region in southern Nigeria with a population representative of Nigerian ethnic groups.
Clinical Case Definition
The diagnosis of stroke was made based on the abrupt onset of focal neurological deficit (hemiparesis, hemiplegia, aphasia, facioparesis, or homonymous hemianopia with or without alteration in level of consciousness)45. Hypertension is defined as systolic blood pressure of > 140mmHg and /or diastolic pressure > 90mmHg or a blood pressure below this figure in previously diagnosed individuals on therapy37. Diabetes mellitus is defined as fasting blood sugar > 119mg% or previous history of diabetes with or without therapy37. Obesity was defined as Body Mass Index > 30kg/m2 and/or waist circumference > 40 cm. Smoking was graded as light < 10 Sticks/ day; moderate 10 - 40 sticks/ day and heavy > 40 sticks/day.
Alcohol consumption was categorized as (i) Heavy > 100gm ethanol / day; (ii) Moderate 50 – 100gm ethanol /day; (iii) Light < 50 gm ethanol/day and (iv) Non - drinker.
Socio-economic stratification was based on income and occupation .
This was done with the aid of the Epi – Info software version 6.04, using the Mantel-Haenszel chi-square test for matched analysis and the odds ratios (OR) to express the level of significance and magnitude of risk factors. The multivariate logistic regression analysis was used to measure the relative contributions of various risk factors.
A total of 160 subjects comprising eighty stroke patients and eighty controls were studied. The mean ages of the patients and controls were 60.58+ 12.42 years and the male/female ratio was 1.2:1 for both groups to ensure one to one matching. Every stroke patient was matched for age and sex with a control (individual matching). The age group 51 – 60 years accounted for majority of stroke patients (33.70%) followed by 61 – 70 years (30%) refer figure 1.
The stroke types were classified using the clinical indices (i.e. level of consciousness, headaches, vomiting, nuchal rigidity, presence of Kernig’s sign and presence of atherosclerosis) and the CT brain scan findings. Majority of the patients had ischemic type (73.75%) while intra-cerebral hemorrhage was found in 23.50% and sub-arachnoid hemorrhage in 3.75%.
RISK FACTOR ANALYSIS
There was no statistical difference between the patients’ and the controls’ levels of education (p > 0.05). Most of the patients belonged to the low socio – economic group (63.75%) but this factor, when compared with the controls, was not a strong factor in predisposing to stroke (OR = 1.37; 95% CI 0.87 – 3.18).
Hypertension was more common in the stroke group (82.50%) than the control group (63.75%). This same trend was observed for diabetes and other risk factors (table I). Thirty four patients, comprising 23% of all patients with both hypertension and diabetes, had both risk factors while only 5 (3%) of the controls had both.
Twenty four (30%) of the patients took alcohol in appreciable amounts compared to fourteen (17.15%) control subjects. This difference did not reach statistical significance (OR=1.9, 95% CI 0.96 – 4.27; X^2= 2.84: p> 0.05). Cigarette smoking was a strong risk factor with odds ratio of 10.01 (95% CI 1.23 – 81.06, X^2=5.23; p< 0.05), though only 11.25 percent of the patients smoked compared to 1.25 percent of the controls. Thirty four (42.50%) of the patients admitted to sedentary life style (with little or no physical exercise) and this increased the risk of stroke about three fold compared to controls (OR 3.2, 95% CI 1.57 - 6.55 ; X^2 =10.62, p < 0.05).
The dietary habit of the patients was not a significant risk factor (OR 1:3, 95% CI 0.78 - 3.09; X^2 = 0.66, p>0.05). Hypertension and diabetes independently increased the risk for stroke by three fold (OR 2.68; 95% CI 1.29 – 5.59 and 3.23; 95% CI 1.09 – 5.71 respectively, p < 0.05) and the presence of both further increased the risk seven fold (OR 7.21; 95% CI 2.61 - 19.75). Obesity, present in 30% of the stroke patients, was associated with eight fold risk (OR 8.53, 95% CI 2.02 - 13.80; X^2 =16.9, p < 0.05).
Though the presence of atrial fibrillation increased the risk of stroke in these patients (OR 2.74; 95% CI 0.60 - 26.16), the observation was not statistically significant, but family history of stroke was significantly associated with increased risk (OR 3.0, 95% CI 1.01 - 5.37; X^2 =6.25, p < 0.05). Furthermore, significant differences were observed in the means of the fasting blood sugar (means for stroke patients and controls were 126.42±67.47mg/dl and 93.20±30.10mg/dl respectively) and the hematocrit levels (means for the stroke patients and controls were 38.49±6.23 and 33.87±9.09 respectively) of the two groups (p< 0.05) but the serum cholesterol levels (means for stroke patients and controls were 174.64±47.75mmol/l and 172.55±34.15mmol/l respectively) were not significantly different (p>0.05). None of the patients or controls had received treatment for hypercholesterolemia. Using multivariate regression analysis, hypertension was the most potent risk factor (p = 0.003) followed by cigarette smoking (p = 0.017), obesity and diabetes mellitus (p=0.023 and p=0.035 respectively).
Fig 1 – AGE DISTRIBUTION OF STROKE PATIENTS
| Risk factors
|| 66 (82.5%)
|| 51 (63.75%)
|| OR 2.68; (95% CI 1.29 – 5.59) p<0.05
|| 21 (26.25%)
|| 10 (12.5%)
|| OR 3.23; (95%CI 1.09 – 5.71) p<0.05
|| 24 (30%)
|| 6 (7.5%)
|| OR 8.53 (95%CI 2.02 – 13.80) p<0.05
| Atrial fibrillation
|| 5 (6.25%)
|| 1 (1.25%)
|| OR 2.74 (95% CI 0.60 – 26.16) p>0.05
| Family history of stroke
|| 20 (25%)
|| 10 (12.5%)
|| OR 3.0 (95% CI 1.01 – 5.37) p<0.05
| Cardiac lesion (1 cardiomyopathy, 1 rheumatic valvular disease)
|| 2 (2.5%)
|| 0 (0%)
|| P >0.05
Despite significant advances in the understanding of its underlying pathophysiology and the development of more effective methods of its management, stroke continues to be a leading cause of mortality and physical disability worldwide [4,7,9,34,41,42]. The basic risk factors for stroke are well known; they include age hypertension, diabetes mellitus, family history of stroke, racial-ethnicity, obesity and hyperlipidemia (dyslipidemia). Most of information on risk factors has been from developed countries.
Studies among Nigerians and other populations in developed countries have shown that of the various modifiable risk factors for stroke, hypertension is one of the most powerful and prevalent factors for first stroke and also an independent risk factor for recurrent stroke and stroke after TIA [8,26,28,30,31,34,35,41-43]. The risk of stroke is strongly related to both systolic and diastolic blood pressure[31,42]. Hypertension and diabetes mellitus are independently associated with increased risks in our patients. Hypertension is the most prevalent risk factor, but the presence of both conferred higher risk than the two factors separately. The relationship between blood pressure and risk for first stroke or recurrent stroke appears to be log-linear throughout normal range, with a 10mmHg rise in mean arterial pressure conferring about 20% to 30% increase in stroke risk [6,42]. It is established that stroke risk is reduced with optimal control of blood pressure, especially of the hemorrhagic type.
Increasing age has been reported to be the strongest risk factor for cerebral infarction, primary intracerebral and subarachnoid bleed [5,14]. The risks of stroke increased from 3 per 100,000 by third and fourth decade to 8 – 9 per 100,000 in the eight and ninth decade . Most of our patients were in the sixth and seventh decade with a slight male preponderance. This result confirmed the observations in most other African studies [30,33-35]. Cigarette smoking was reported to be insignificant in earlier studies among Nigerians [30,34] but our study revealed that it is a strong risk factor. This result is consistent with the findings from the MRFIT  study in developed western countries. The earlier Nigerian studies had fewer numbers of patients and were retrospective, and it is possible that more Nigerians now indulged in cigarette smoking than before.
Elevated serum cholesterol which has been strongly associated with increased mortality from ischemic stroke in western countries has not been a significant factor among Africans [11,42]. The role of diet is not important in our study and has also not been substantiated in the past. This may be responsible for the relatively lower levels of serum cholesterol of the stroke patients and the controls.
Furthermore, obesity, the presence of atrial fibrillation and sedentary life style (physical inactivity) were all associated with increased risk of stroke in our study as has been previously documented . The family history of stroke was also associated with an increased risk in our study. This may be related to inherent biological traits like gender, physical characteristic, and also the presence of familial risk factors like hypertension, obesity and non-insulin dependent diabetes mellitus.
Though we did not evaluate the role of gender, more males were noted to have suffered stroke during the study period. Earlier studies from developed countries also reported slight preponderance of males, especially in middle-age[2,5,6] similar to our observation. The male sex is a risk factor especially for thrombotic stroke, until the eight and ninth decades when gender plays no role in enhancing risk [2,3,29] but the reason for this is not quite obvious. It may be that the female sex hormones are protective before menopause or that the females tolerate hypertension better than the males. The other possibilities include the influence of cultural factors, like the ready accessibility of males to health care and the greater life expectancy found in women. It is also possible that the sex preponderance may be real.
Significant differences were observed in the hematocrit levels of the patients and controls. The direct relevance of this is unclear, though the hypercoagulable states like polycythemia is a risk factor for stroke, the levels noted in our patients did not reach polycythemic levels.
There are other hypercoagulable states like homocysteinuria and primary coagulopathies (antithrombin III, protein S and C deficiency, factor V Leiden and prothrombin 202A gene mutation)25 that predispose and contribute to pathophysiology of stroke, most of which are not routinely screened for in many developing countries, including Nigeria. The presence of antiphospholipid antibodies is relatively a well established, novel risk factor for ischemic stroke in young females , but the extent to which these antibodies augment risk is not well characterized. We lack facility for detecting anti-phospholipid and anti-cardiolipin antibodies in our patients.
It is now recognized that transient ischemic attacks (TIAs) are frequent and important precursors of stroke and other vascular ischemic events [18,40,42]. Coronary heart disease, peripheral vascular disease and presence of carotid bruits have not been shown to be very important[31,42], but there are reports of cases in Africans with obliterative arteritis [2,12]. More recently, high fat and sodium diets 38 have been linked to stroke as well as hypokalemia .
This prospective, case control study has shown that hypertension is still the dominant risk factor for stroke among Nigerian Africans with significant enhancement of risk in the presence of diabetes mellitus. Cigarette smoking, physical inactivity and obesity were important risk factors as well, but hypercholesterolemia, alcohol ingestion and dietary habits were not important risks.
HEMATOME SOUS DURAL, COMPLICATION DU TRAITEMENT CHIRURGICAL DES HYDROCEPHALIES. NOTRE EXPERIENCE A DAKAR
Fig 1 – AGE DISTRIBUTION OF STROKE PATIENTS
L’hématome sous dural est une complication observée lors du traitement chirurgical de l’hydrocéphalie. Avant l’avènement de la tomodensitométrie à Dakar, une incidence de 0,8 % était trouvée.
L’objectif de notre travail est de réévaluer cette incidence à la lumière de cet examen et de déterminer les divers facteurs étiologiques.
Patients et Methode
Nos patients ont été opérés par dérivation ventriculo-péritonéale et sont âgés de 8 à 30 ans au moment du diagnostic. Quatre sont de sexe féminin. Le signe le plus fréquent est l’hypertension intra-cranienne. La tomodensitométrie a établi le diagnostic dans tous les cas. Elle montrait dans 4 cas, un hématome unilatéral et dans deux cas, une forme bilatérale. D’importantes calcifications sont retrouvées dans deux cas. Cinq patients ont été opérés et nous notons deux décès. Les valves utilisées sont à débit de drainage fixe.
Il existe une augmentation de l’incidence par rapport à notre première série datant de 12 ans.
Par rapport aux autres systèmes de drainage, nous ne notons pas de différence significative. Aucun facteur étiologique déterminant n’est retrouvé.
Cette complication pouvant pauci-symptomatique, la réalisation d’examens tomodensitométriques systématiques permettrait de constater une plus grande fréquence de cette complication.
Subdural hematoma is a complication which can occur seen after setting a shunt for hydrocephalus. Prior to CT scan installation in Dakar, the incidence was 0,8%.
Our aim is to consider twelve years later this complication and others causal factors. Six patients were observed, between 8 and 30 years. Four of them were female. The main sign is increased intra cranial pressure. CT scan shows the hematoma : two bilateral and two calcified.Two patients deceased after surgical treatment.
The frequency is not due to shunt type or any specific cause.
The complication may occur without clinical complain and CT scan for all surgically treated patient is mandatory.
Mots cles : Afrique, dérivation ventriculo-péritonéal, hématome sous dural, hydrocéphalie, valve, Sénégal, Africa, subdural hematoma, hydrocephalus, shunt, Senegal
L’hématome sous dural est une complication observée lors du traitement des hydrocéphalies. La fréquence varie considérablement d’une série à l’autre (1, 5, 8, 10). Avant la disponibilité de la tomodensitométrie à Dakar, BADIANE (3) a rapporté une incidence de 0,8 %. Notre objectif est, douze ans plus tard de réévaluer la fréquence et les facteurs étiologiques de l’affection.
PATIENTS ET METHODES
De 1994 à 2003 six patients porteurs d’hématome sous dural au décours d’un traitement chirurgical de l’hydrocéphalie ont été recensés. Durant la même période, 430 patients ont été recensés et opérés. La dérivation ventriculo-péritonéale(DVP) a été utilisée dans tous les cas Ils ont tous bénéficié d’une preuve tomodensitimétrique de l’hématome sous dural et été opérés. Le suivi a été de deux à six ans.
Nos observations sont résumées dans le tableau ci-dessous:
La survenue d’un hématome sous dural au décours du traitement chirurgical de l’hydrocéphalie est rapportée par plusieurs auteurs. La fréquence varie cependant de façon importante : de 1 à 10 % (2, 4, 6). L’incidence observée dans notre série est de 1,4 %. Par rapport à la première série, il existe une nette augmentation. Il est à signaler cependant que les moyens diagnostiques notamment tomodensitométriques deviennent de plus en plus accessibles aux populations pouvant ainsi expliquer cette hausse.
Il existe une nette prédominance des branches d’âge de 0 à 15 ans (9,13). La majorité de nos patients se situe dans cette tranche d’âge (5/6). Notre pays se caractérise par la jeunesse de sa population dont plus de la moitié a moins de 18 ans. Les hydrocéphalies de l’enfant représentent plus de 80 % des hydrocéphalies.
La constitution de l’hématome résulte à un phénomène hydrostatique d’élévation du flux dans le shunt, favorisé par la position orthostatique (10).
La plupart des valves sont des régulateurs de pression. Elles remplissent la tête grâce à un mécanisme de trajet unidirectionnel taré à une pression d’ouverture donnée. Les basses pressions sont inférieures à 40 mm H20, les moyennes de 40 à 80 mm d’eau et les hautes pressions sont supérieures à 80 mm d’eau. Nous avons le plus souvent utilisé des valves de type moyenne pression fixe. L’hématome sous dural a été cependant constaté dans tous les types de valve : 10 % dans les valves moyenne pression, 16 % dans les valves en haute pression et 13 % dans les valves en basse pression (7,13).
L’étiologie n’a également pas d’incidence notable dans la survenue de la collection
L’espoir a résidé un temps sur les valves à pression ajustable qui offrent deux avantages : la possibilité de procéder à l’ajustement de la pression d’ouverture dès le début des signes d’alarme la possibilité d’obtenir un débit de drainage proche de l’équilibre hydrodynamique.
Les hématomes sous duraux ont également été observés dans ces types de valve. L’ajustement de la pression d’ouverture n’a pas toujours permis d’éviter l’intervention chirurgicale (7,15).
Les valves munies d’un système antisiphon ont pour avantage de n’être sensibles qu’aux pressions d’amont, maintenant de ce fait une PIC toujours positive . Elles sont freinées en position orthostatique, pour éviter les hyper débits. L’incidence respective de l’hématome sous dural dans ces cas varie de 2 à 3 % (15).
Le diagnostic tomodensitométrique de l’hématome ne pose guère de problème. Dans les formes vues tardivement, les calcifications sont visibles à la radiographie standard.
L’indication de l’évacuation chirurgicale de l’hématome sous dural doit être posée sur des critères de tolérance clinique (15). Tous nos patients ont été reçus porteurs de signes de souffrance neurologique. Elle consiste en une évacuation de l’hématome après trou de Trépan. Bret y associe une membranectomie lorsqu’il persiste une collection. La double trépanation est effectuée dans les formes bilatérales. Elle peut être suivie de réglage de la valve ou ligature du cathéter distal (12).
Dans les formes asymptomatiques, les examens tomodensitométriques répétés permettent de suivre l’évolution de la collection qui peut rester stable, se résorber ou s’accroître (8). Du fait de l’impossibilité de pratiquer cet examen de façon répétée pour la plupart de ces patients, nous sommes adeptes de l’intervention systématique.
Le shunt idéal n’est pas encore disponible puisqu’il doit obéir à deux conditions : prévention de l’hyperdrainage et correction immédiate des volumes modifiés par les variations de position du corps. Malgré l’utilisation quasi systématique de valves à débit de drainage fixe, l’incidence des hématomes sous duraux consécutifs à une dérivation interne n’est pas supérieure à celles rapportés dans la littérature. L’existence de formes asymptomatiques doit cependant inciter à réaliser des examens tomodensitométriques systématiques à distance de l’intervention chirurgicale. L’augmentation de l’incidence depuis l’avènement de la tomodensitométrique à Dakar nous conforte dans cette conviction.