STROKE





STROKE :

The term " stroke" ( syn: apoplexy) is applied to acute severe manifestations of cerebrovascular disease. It causes both physical  and mental crippling .WHO defined stroke as " rapidly  developed  clinical signs of focal disturbance  of cerebral function; lasting more than 24 hours or leading  to death, with no apparent cause other than vascular  origin". The 24 hours threshold in the definition excludes transient ischaemic  attacks ( TIA).


 The disturbance  of cerebral function is caused by three morphological  abnormalities,  i.e., stenosis, occlusion or rupture of the arteries.Dysfunction of the brain ( " neurological deficit") manifests itself by various  neurological  signs and symptoms that are related to  extent and site of the area  involved  and to the underlying  causes. These include coma, hemiplegia, paraplegia, monoplegia, multiple  paralysis,  speech disturbances , nerve persist, sensory important, etc.Of these hemiplegia constitutes  the main somatoneurological  disorder  in about 90 per cent of patients. 

    
 Stroke includes a number of syndromes with differing  aetiologies,  epidemiology,  prognosis and treatment. These are listed below: 

(a) Subarachnoid haemorrhage 

(b) Cerebral haemorrhage 

(c) Cerebral thrombosis or embolism 

(d) Occlusion of pre_ cerebral arteries 

(e) Transient cerebral ischemia ( of more than 24 hours)

(f)  III_ defined cardiovascular disease (i.e., the underlying  pathology in the brain is not determined).






1.Risk Factors 

  Epidemiological studies have indicated  that stroke doe not occur at random, and there are factors ( risk factors) which precede stroke by several years. These are : 

(a) Hypertension  : This is considered  the main risk factor for cerebral thrombosis as well as cerebral haemorrhage; 


(b) Other factors : Additional  factors  contributing to risk are cardiac abnormalities  (i.e., left ventricular hypertrophy, cardiac dilatation), diabetes, elevated blood lipids, obesity, smoking,  glucose intolerance,  blood clothing  and viscosity,  oral contraceptives,  etc. Although the risk factors  for stroke are similar  to those for CHD, their relative importance differs.


2. Transient ischaemic attacks  ( TIA) 

  One phenomenon  that has received  increasing  attention  is the occurrence of TIA in a fair proportion  of cases. These are episodes  of focal, reversible , neurological  deficit of sudden  onset and of less than 24 hours  duration. This is result of temporary disruption  of circulation  to part of the brain. They show a tendency  to recurrence.They are due to microemboli, and are a warning sign of stroke.


HOST FACTORS 

(i) Age : Stroke  can occur at any  age. Usually  incidence  rates steeply  with age.In developed countries , over 80 per cent   of all stroke deaths occur in persons over 65 years. In India, about one_ fifth of all strokes occur below the age of 40 ( called " stroke in the young"). This is attributed  to our " young population ", and shorter life expectancy  ( about 65 years)'.


(ii) Sex : The incidence rates are higher in males than females  at all ages.

(iii) Personal  history  : The WHO Study showed that nearly three  _ quarters of all registered smoke patients  had associated diseases,  mostly  in the cardiovascular  system or of diabetes.  This supports the view that in  most cases stroke is merely  an incident in the slowly  progressive  course of a generalised  vascular  disease. 





Stroke control  programme:

  The aim of a stroke  control  programme  is to  apply at community  level effective  measures for the prevention  of stroke. The first priority  goes to control of arterial hypertension  which is a major cause of stroke. As transient ischaemic attacks (TIA) may be one of the earliest manifestations of stroke, their early detection and treatment is important  for the prevention  of stroke. Control of diabetes, elimination of smoking , and prevention  and management  of other risk factors  at the population  level are new approaches. Treatment  for acute stroke is largely the control of complications. Facilities for the long_ term follow_ up of patients  are essential. The education  and training  of health personnel  and of the public form an integral part of the programme. For any such programme, reliable knowledge of the extent of the problem in the community  concerned is essential. 


  In summary, control of stroke that was once considered  an inevitable accomplishment to ageing is now being approached through primary prevention. It has generated the hope that stroke can be tackled  by community  health  action. 





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