Asthma is a condition in which the airways are narrowed because hyper-reactivity to certain stimuli, produces inflammation; the airway narrowing is reversible.
I have been asked donkey times by asthma patients ; “Doc What actually causes asthma”? Before I could even ramble through the mumbo-jumbo of the medical jargon, of what causes asthma, both the patient and I will become more confused. Okay, let me try to break down the causes of asthma into a b c for the uninitiated.
Asthma affects 22 million people in Nigeria, according to research work in University of Jos by Prof Iheme, between 1982 and 1992-(10-year-study), the number of people with asthma increased by 42 percent.
The condition also seems to be becoming more serious, requiring more people to be hospitalized. Between 1982 and 1992 according to the study, the death rate from asthma in Nigeria increased by 35 percent.
Remember that a former Vice Chancellor, a Professor and a Physician died of acute asthmatic attack, when he visited his village and forgot his asthma drugs. When the attack occurred, he died before he could be rushed to the nearest health facility for help.
Most of my patients, often require intra-venous administration of aminophylline and hydrocortisone, during attacks before they could get better. Imagine a situation where an asthmatic has an acute attack and neither aminophylline nor a nebulizer could be assessed. Death becomes the ultimate, like the Vice Chancellor. God forbid.
A note of warning. If you are an asthmatic, please get to your doctor now, let him pack an emergency bag for you, which you must carry whenever you are traveling to areas where it will be difficult to assess medical facilities. Now shall we discuss asthma.
What causes asthma?
1. In a person with asthma, the airways narrow in response to stimuli, that do not affect the airways in normal lungs – science has not actually proven why this is so.
2. The narrowing can be triggered by many stimuli such as – pollens, dust mites, animal dander, smoke, cold air newly painted buildings, exercise, etc etc.
3. In an asthmatic attack, the smooth muscles of the bronchi go into spasm, and the tissues lining the airways swell from inflammation and secrete mucus into the airways (a condition called bronchoconstriction), the narrowing requires the person to exert more effort to move air in and out.
4. Certain cells in the airway, particularly the mast cells, are thought to be responsible for initiating the airway narrowing. Mast cells through out the bronchi release substances such as histamine and leukotrienes, that cause smooth muscle to contract, mucus secretions increase and certain white blood cells to migrate to the area. Mast cells can be triggered to release these substances in response to something they recognize as foreign(an allergen), such as pollen etc.
5. However asthma is also common and severe in many people without defined allergies.
6. When someone with asthma exercises or breathes cold air, a similar reaction occurs.
7. Stress and anxiety also can trigger Mast cells to release histamine and leukotrienes. Eosinophils, another type of cell found in the airways of people with asthma, release additional substances including leukotrienes and other materials contributing to airways narrowing. Most students develop frequent asthmatic attacks when their examinations are near due to anxiety and stress.
Is asthma hereditary?
Asthma can be caused by both hereditary and inherited factors. Just because you have a parent with asthma or an allergy does not mean you will have it too.
Researchers in Oxford University have found that the gene responsible for asthma, hay fever and other allergy-type illnesses is active only when inherited from the mother. If inherited from the father, the offspring is less likely to suffer from these illnesses.
Does asthma run in the family?
Asthma often runs in the family, although not every one in the family will have it. Only those that inherited the gene from their mother. Many people with asthma may also have hay fever or eczema, and a family history of these conditions. A child is more likely to have asthma if these other conditions exist in the family.
Today I concentrated oly on causes of asthma. Next week we shall discuss symptoms and management of asthma. Always be medically guided.
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