Asthma is a major noncommunicable disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. Symptoms may occur several times in a day or week in affected individuals, and for some people become worse during physical activity or at night. During an asthma attack, the lining of the bronchial tubes swell, causing the airways to narrow and reducing the flow of air into and out of the lungs. Recurrent asthma symptoms frequently cause sleeplessness, daytime fatigue, reduced activity levels and school and work absenteeism. Asthma has a relatively low fatality rate compared to other chronic diseases.
Facts about asthma
- WHO estimates that 235 million people currently suffer from asthma. Asthma is the most common noncommunicable disease among children.
- Asthma is a public health problem not just for high-income countries; it occurs in all countries regardless of the level of development. Most asthma-related deaths occur in low- and lower-middle income countries.
- Asthma is under-diagnosed and under-treated. It creates substantial burden to individuals and families and often restricts individuals’ activities for a lifetime.
The causes
The fundamental causes of asthma are not completely understood. The strongest risk factors for developing asthma are a combination of genetic predisposition with environmental exposure to inhaled substances and particles that may provoke allergic reactions or irritate the airways, such as:- indoor allergens (for example, house dust mites in bedding, carpets and stuffed furniture, pollution and pet dander)
- outdoor allergens (such as pollens and moulds)
- tobacco smoke
- chemical irritants in the workplace
- air pollution.
Urbanization has been associated with an increase in asthma. But the exact nature of this relationship is unclear.
Pathophysiology
Asthma is the result of chronic inflammation of the conducting zone of the airways (most especially the bronchi and bronchioles), which subsequently results in increased contractability of the surrounding smooth muscles. This among other factors leads to bouts of narrowing of the airway and the classic symptoms of wheezing. The narrowing is typically reversible with or without treatment. Occasionally the airways themselves change. Typical changes in the airways include an increase in eosinophils and thickening of the lamina reticularis. Chronically the airways' smooth muscle may increase in size along with an increase in the numbers of mucous glands. Other cell types involved include: T lymphocytes, macrophages, and neutrophils. There may also be involvement of other components of the immune system including: cytokines, chemokines, histamine, and leukotrienes among others.Reducing the asthma burden
Although asthma cannot be cured, appropriate management can control the disease and enable people to enjoy a good quality of life. Short-term medications are used to relieve symptoms. Medications such as long-term inhaled steroids are needed to control the progression of severe asthma.People with persistent symptoms must take long-term medication daily to control the underlying inflammation and prevent symptoms and exacerbations. Inadequate access to medicines is one of the important reasons for the poor control of asthma in many settings.
Medication is not the only way to control asthma. It is also important to avoid asthma triggers - stimuli that irritate and inflame the airways. With medical support, each asthma patient must learn what triggers he or she should avoid.
Although asthma does not kill on the scale of chronic obstructive pulmonary disease (COPD) or other chronic diseases, failure to use appropriate medications or to adhere to treatment can lead to death.
Key facts
- Asthma is one of the major noncommunicable diseases. It is a chronic disease of the the air passages of the lungs which inflames and narrows them.
- Some 235 million people currently suffer from asthma. It is a common disease among children.
- Most asthma-related deaths occur in low- and lower-middle income countries.
- The strongest risk factors for developing asthma are inhaled substances and particles that may provoke allergic reactions or irritate the airways.
- Medication can control asthma. Avoiding asthma triggers can also reduce the severity of asthma.
- Appropriate management of asthma can enable people to enjoy a good quality of life.
WHO strategy for prevention and control of asthma
WHO recognizes that asthma is of major public health importance. The Organization plays a role in coordinating international efforts against the disease. The aim of its strategy is to support Member States in their efforts to reduce the disability and premature death related to asthma.WHO's programme objectives are:
- surveillance to map the magnitude of asthma, analyse its determinants and monitor trends, with emphasis on poor and disadvantaged populations;
- primary prevention to reduce the level of exposure to common risk factors, particularly tobacco smoke, frequent lower respiratory infections during childhood, and air pollution (indoor, outdoor, and occupational exposure); and
- improving access to cost-effective interventions including medicines, upgrading standards and accessibility of care at different levels of the health care system.
Global Alliance against Chronic Respiratory Diseases:
The Global Alliance against Chronic Respiratory Diseases (GARD) contributes to WHO’s work to prevent and control chronic respiratory diseases. It is a voluntary alliance of national and international organizations and agencies from many countries. It focuses on the needs of low- and middle-income countries and vulnerable populations, and fosters initiatives that are tailored to local needs.Also read: Bronchial asthma vs Cardiac asthma
Reference(s):
1). World Health Organization: Asthma - Media Center. Accessed 26 September 2016. Available here: http://www.who.int/mediacentre/factsheets/fs307/en/
2). Centers for Disease Control: Asthma. Accessed 26 September 2016. Available here: https://www.cdc.gov/asthma/
3). Wikipedia, The Free Encyclopedia: Asthma. Accessed 26 September 2016. Available here: https://en.wikipedia.org/wiki/Asthma
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