Dr. Shyam P Lohani

The World Stroke Day is observed on October 29 every year to underscore the nature and high rates of stroke with the focus on prevention and treatment of the condition and ensure better care and support for the survivors. Stroke is one of the leading causes of death in Nepal, with about 3,000 people dying of it in the country annually.
Stroke occurs due to a decrease or blockage in the blood supply to the brain. Stroke follows when a blockage or bleed of the blood vessels either interrupts or reduces the supply of blood to the brain cells. The consequences of reduction or interruption of blood supply cause a lack of enough oxygen or nutrients to the brain, and brain cells start dying. In simple terms, stroke affects the blood vessels that feed oxygen to the brain. If the brain does not receive enough oxygen, damage may start to occur which ranges from mild, severe to deadly.
Worldwide, stroke is ranked as the second leading cause of death with an annual mortality rate of about 5.5 million. The burden of stroke seems to be shifting to the developing world where there are 4.85 million stroke deaths and 91.4 million disability-adjusted life years (DALYs) annually compared with 1.6 million deaths and 21.5 million DALYs in developed countries.

Threats
Generally, strokes are of two major categories: ischemic stroke and hemorrhagic stroke. On one hand, ischemic stroke is caused by interruption of the blood supply to a part of the brain resulting in a sudden loss of function, while hemorrhagic stroke is attributed to rupture of a blood vessel or an abnormal vascular structure, on the other hand. In general, ischemic stroke accounts for about 80 per cent of stroke cases while hemorrhagic stroke accounts for 20 per cent. But the actual proportions of stroke types depend on the population.
A wide range of stroke risk factors have been identified. They are important for both the primary and secondary prevention of stroke. The traditional risk factors of stroke can be classified into two, which include modifiable and non-modifiable. The modifiable risk factors of stroke include hypertension, diabetes mellitus, stress, obesity, high blood cholesterol level, cardiovascular diseases, sedentary lifestyle, atrial fibrillation, smoking, heavy alcohol consumption, and poor diet are responsible for about 90 per cent of all strokes. Thus, these risk factors that are predominantly traditional risk factors of stroke are modifiable, making stroke a highly preventable condition. The non-modifiable risk factors are, however, relatively few and include factors such as age, gender, and ethnicity.
The high burden of stroke is partly owing to poor community knowledge of its risk factors and associated warning signs. There have been pieces of evidence that increased awareness of stroke risk factors leading to improved compliance with stroke prevention practices while lack of recognition of stroke warning signs is an important causal factor of delay in receiving appropriate care at the hospital and increase in mortality.
Stroke is a medical emergency. Although the majority of strokes are treatable, some can lead to disability or even death. Each type of stroke has been associated with a set of potential causes. Generally, stroke is more likely to affect persons if they have overweight or obesity, who are 55 years of age or older, have a personal or family history of stroke or high blood pressure. Those who are suffering from diabetes, high cholesterol, heart disease, carotid artery disease, or another vascular disease, following a sedentary lifestyle, consuming alcohol excessively, and using illicit drugs are also at risk of stroke.
Prevention of the occurrence of new strokes is the key solution to the problem of the growing stroke burden worldwide. The WHO in its recent advice advocates a combination of population-wide and high-risk approaches to preventing stroke and other types of cardiovascular diseases (CVD). The high-risk prevention strategy involves the determination of the absolute risk of CVD to help identify people at high risk of developing acute CVD.
The population-wide prevention strategy targets several behavioural and lifestyle risk factors and it is important because even small favourable changes in the distribution of risk factors could lead to major reductions in stroke and CVD incidence in the population. Other primary prevention strategies of stroke include nationwide community-based education programmes on the identification of risk factors and prevention strategies. In the control of stroke, prevention of secondary vascular events becomes an important consideration. Appropriate control of blood pressure is of paramount importance as the reduction of which decreases the risk of subsequent strokes for both ischemic and hemorrhagic stroke.

Prevention
The best way to prevent a stroke is to address its underlying causes. Public health approaches can achieve this by making lifestyle changes such as eating a healthy diet, maintaining a moderate weight, exercising regularly, not smoking tobacco, avoiding alcohol, or only drinking moderately and eating a nutritious diet means including plenty of fruits, fresh vegetables, whole grains, nuts, seeds, and legumes.
It is important to limit the amount of red and processed meat in the diet, as well as cholesterol and saturated fats. Also, moderate salt intake to support healthy blood pressure levels is equally important. Other measures a person can take to help reduce the risk of stroke include managing diabetes and getting treatment for heart disease. As well as making these lifestyle changes, taking anticoagulant or antiplatelet medications can also reduce the risk of experiencing subsequent strokes.

(A Professor, Lohani is the founder and academic director of Nobel College. lohanis@gmail.com)