THE MYSTERIES OF STROKE

Dr David G Smithard MD FRCP

Consultant in Stroke and Elderly Medicine, King’s College Hospital, London.

   

Dr Smithard has been a consultant in stroke and elderly medicine for 20 years. His main research interests are in stroke rehabilitation and dysphagia (Swallowing problems). He is the President of the UK Swallowing Research Group, a member of the British Association of Stroke Physicians and a the European Society for Swallowing Disorders.

Introduction

Stroke does not respect age, and occurs across the full age spectrum. In the West the stroke is predominantly a disease of old people, where as in Nigeria and other African countries, amongst the Black population, stroke is more likely to affect younger adults.

Age distribution of Stroke in Nigeria (Sokoto)

Stroke is a common problem across the world.  In 2010 17m people suffered a stroke, and there were 33million people who had suffered a stroke at some time. Stroke is a major cause of death across the world and worldwide, 10% (5 ½  million) deaths are due to stroke.  In recent years there has been a 25% increase in the number of people suffering a stroke in the 20-64 years age group. Stroke accounts for 3% of medical admissions to hospital.  Stroke is a medical diagnosis; a definitive diagnosis requires brain scans to exclude other neurological problems that might appear to be a stroke (brain tumour, dementia) and to help determine the type of stroke and exactly where in the brain a stroke has occurred.

      

   Stroke caused by a blocked                   Stroke caused by a burst blood vessel

What is a stroke?

Despite the many risk factors (reasons for a stroke occurring) for stroke, the one common final pathway is an interruption of the blood supply to an area of the brain. This may be due to a blockage of a blood vessel or the bursting of a blood vessel (see figure). The best way to tell the difference is by a CT scan of the brain. People have tried to tell the difference by using scoring systems based on the way the stroke occurred (speed of occurring, risk factors and conscious level) but these scoring systems are not accurate enough. The differences are important in that the treatment is different.

Stroke is a disease of the blood system, that results in neurological problems, secondary to damage to the brain. Stroke caused by a blocked blood vessel (ischaemic) causes most of the strokes in Europe and the USA, with only 20% being due to a burst blood vessel (or haemorrhage); in Nigeria, approximately 30% of strokes are caused by a burst blood vessel.  This damage to the brain is real and the physical consequences are real. Within the rural settings, some consider stroke to be a spiritual disease, and may therefore seek spiritual support over medical support.

In Nigeria and other areas in Africa, those of African descent are more likely to have a stroke than Caucasians, as are those of a lower social class.

Why do people have stroke?

There are many factors that increase the risk of stroke. Across the world the commonest cause is hypertension or high blood pressure (see box). Many people may not know that they have high blood pressure, may not be adequately treated or may not take their medication. High blood pressure does not cause any symptoms until it has caused damage. Very high blood pressure may result in brain swelling and fits, high blood pressure may result in stroke and kidney disease, and to a lesser degree, heart disease.

Other factors that can increase the risk of stroke (table 10 include alcohol, smoking, obesity, diabetes, sickle cell disease (7-10% of stroke in those <20), dehydration, malnutrition, drug abuse and HIV (7% of stroke in young people), poor diet and lack of exercise. Even after many investigations 35% of people will have no clear reason as to why they have had a stroke.

The use of drugs such as Acid, Heroin or Cocaine are all associated with a small but definite increase in stroke risk. This may be due to a rise in blood pressure, but at the same time could be due to an inflammation of the blood vessels resulting in a blood vessel becoming blocked secondary to this.

These factors in themselves do not cause stroke, but act via other mechanisms.  For instance, obesity will cause diabetes, and hypertension, alcohol affects the blood cells and can lead to  hypertension. HIV can increase the ability of the blood to clot and in general causes a stroke by a clot forming in the blood vessel or a clot coming from the heart. Sometimes stroke may occur in the context of lymphoma associated with HIV.

How does stroke affect me?

The treatment of stroke is not always easy and not everyone makes a good recovery. The medical treatments do not help everyone, and do not always prevent stroke occurring again (but may reduce the chance of it happening again)and may not prevent you dying. The best thing to do is to prevent stroke happening in the first place. Once the stroke has happened, it is about preventing complications (table 2); this involves many people other than doctors, the team will consist of physiotherapists, occupational therapists, dietitians, and nurses.

Recovery from stroke often takes a long time, in some cases many years and for others no recovery of any meaningful benefit will occur.

Stroke is important because of the effects it can have on your life. It is not just the physical problems, such as your arm and / or leg not working, but also the ability to swallow and in some people the ability to speak, think, to able to communicate and be understood.

The inability to communicate (talk or understand what is being said to you) can have a major impact on your ability to live independently. The less noticeable effects of stroke that can have a major impact on your social life are anger, depression, poor concentration and poor memory (forgetfulness). These can lead to isolation, break up of relationships and loss of work.

Stroke also kills; many young people die of stroke in the continent of Africa, Nigeria is no exception.

Prevention

The best thing to do is to reduce your risk of having a stroke. The simple things are the best. Eat sensibly, do not smoke, do not take illicit drugs, drink alcohol sensibly and take exercise.