Sunday, 11 October 2015

WHAT IS A STROKE, AND WHAT CAN YOU DO TO PREVENT IT?

By: Rohit Bhattacharjee, Rita Krishnamurthi, Valery Feigin



National Institute for Stroke and Applied Neurosciences, AUT University, Auckland, New Zealand

Stroke is one of the biggest causes of disability and death in the world. In Nigeria, it is estimated that strokes are responsible for between 5 to 17% of all medical deaths per year. In addition to this, strokes have enormous economic, psychological and social burden for patients, families and caregivers. However, despite the huge impact of stroke, very few people outside the health sector are aware of what a stroke is, how to identify a stroke, what the risk factors of stroke are and how they can reduce their chances of having a stroke. This article will aim to answer some of those questions, and give people the information needed to prevent them from suffering a stroke.


What is a stroke?

A stroke is a medical emergency where blood circulation in the brain is disrupted, due to either a blockage in the blood vessel (ischaemic stroke) or if the blood vessel ruptures or bursts (haemorrhagic stroke). This results in a part of the brain not receiving adequate blood supply, which leads to the death of brain cells in the affected part. The severity of symptoms is related to where in the brain the disruption occurs, as this affects how much of the brain (and which area of the brain) is affected.
Sometimes, the blockages can be temporary. If symptoms last for less than 24 hours, the event is called a Transient Ischaemic Attack (also known as TIA or mini-stroke). These may be warnings for more severe strokes in the future and one should always seek medical attention – even if the symptoms go away quickly.
However, the impact of stroke can be greatly minimised if people act quickly and seek medical attention as soon as possible.


How can you tell if someone is having a stroke?

The F.A.S.T. is an easy way to detect some sudden signs and symptoms of a stroke and prompt immediate actions:

Face drooping: Does one side of the face droop? Ask the person to smile. Is the face symmetrical?

Arm weakness: Is one arm weak or numb? Ask the person to raise both arms. Does one arm drift downward?

Speech difficulty: Is speech slurred, are they unable to speak or understand? Ask the person to repeat a simple sentence.

Time to call: Time to call an ambulance if the person shows any sign of these symptoms, even if the symptoms go away very quickly

Although two thirds of strokes occur without any warning signs, approximately one third of strokes do have warning signs, including transient ischaemic attack (TIA or mini stroke). An ambulance should be called immediately if any of the following symptoms occur (especially symptoms with sudden onset):
·         loss of strength (or sudden clumsiness – such as being unable to stand up, or dropping items) in some part of the body, espeically on one side, including the face, arm or leg;
·         numbness (sensory loss) or other unusual sensations in some part of the body, especially if one-sided;
·         complete or partial loss of vision on one side;
·         inability to speak properly or to understand language;
·         loss of balance, unsteadiness or an unexplained fall;
·         any other kind of transient spells (vertigo, dizziness, swallowing difficulties, acute confusion, or memory disturbances);
·         headache that is unusually severe, abrupt, or of unusual character (including unexplained change in the pattern of headaches);
·         sudden alterations of consciousness or convulsions/seizures etc.
These warning signs may occur alone or in any combination. They may last a few seconds or up to 24 hours and then disappear (TIA), or as a single episode during a day or repeated. During the first 24 hours it is impossible to know for sure if symptoms are due to stroke or due to TIA. However, symptoms can indicate a hidden problem with blood flow in the brain, which, if ignored, could result in a severe stroke.


What are the risk factors of stroke?

While stroke is a serious health issue, current research suggests that upto 80% of strokes are preventable.
The main risk factors for stroke are:
  • High blood pressure (hypertension): The lower your blood pressure, the lower your risk of stroke. The usually recommended target for blood pressure reduction is blood pressure below 140/90 mm Hg (or below 130/80 mm Hg in diabetics). 
  • Heart disease: People with heart disease, atrial fibrillation and left ventricular hypertrophy are at significantly higher risk of stroke. Regular medical advice on controlling these conditions are essential in reducing stroke risk.
  • Diet and lifestyle: A healthy lifestyle and well balanced diet can significantly reduce your chances of having a stroke. What you eat and how often you exercise should be balanced to maintain a healthy body weight.
  • Smoking and alcohol: Smoking tobacco makes you 4 times more likely to have a stroke. Smoking constricts and hardens the arteries throughout the body, thus reducing the blood flow, and makes the blood more likely to clot. Even second hand smoking (being in the same room as someone smoking) can increase your risk of stroke significantly.

There are some risk factors for stroke that we cannot control. Your age, sex, ethnicity and genetics can influence your risk of stroke, but the effects of these factors is greatly reduced if you the controllable risk factors are well managed.


How high is your risk?

Unfortunately, even if someone is trying to manage the risk factors, it is very hard to determine what their actual risk of stroke is. Until recently, the only way to determine if you were at risk of stroke was if your doctor told you. However, the National Institute for Stroke and Applied Neurosciences has recently developed an app that can calculate your risk of stroke. The Stroke Riskometer™ is available for both Android and iPhone platforms, and assesses both absolute risk (i.e. how likely you are to have a stroke in the next 5 or 10 years) as well as relative risk (i.e. how likely you are to have a stroke compared to someone your age and sex with no risk factors). Relative risk is particularly important in trying to determine whether you need to make any changes to your lifestyle, as the absolute risk (particularly for young people) can often be quite low. In addition to your risk factor, the app also lets you see what your risks are, and in the Pro version, gives you guidance on what you can do to minimise these risks. More information is available at www.strokeriskometer.com

Having a stroke is a serious incident with potentially devastating consequences. However, you can greatly lower your risk of having a stroke by being aware of what your risk factors are, and taking the correct steps to maintain a healthy lifestyle.




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