Asthma is a common disorder of airways which is chronic. It is complex and is characterized by inconsistent and recurring symptoms like inflammation and spasm of the bronchi and air flow obstruction due to narrowing of the airway.
The causes of asthma are not well understood but the pathogenic mechanism is similar in all the asthma patients. More than 300 million people suffer from asthma worldwide. The incidence of asthma ranges from 3.5 percent to 20 percent of population in every country.
Family history of asthma is one of the most important factors for asthma. High exposure to in-house allergens in infancy and childhood may cause asthma. Lesser exposure to infectious diseases increases the risk of asthma. Viral infections of the lower respiratory tract may cause asthma however viral infections of upper respiratory tract are found to be protective against asthma. Other causes for asthma include exercise induced asthma and occupational asthma.
The possibility of asthma in an individual depends on genetic, social and environmental factors. Tobacco smoke polluted air, high ozone levels in air, use of antibiotics in early life and psychological stress are also found to be causes of asthma. Presence of specific genes (more than 100 genes have been identified) is responsible for development of asthma.
Asthma as a result of – or worsened by – workplace exposure is the world's most commonly reported occupational respiratory disease. Estimates by the American Thoracic Society (2004) suggest that 15–23 percent of new-onset asthma cases in adults are work related. Animal proteins, enzymes, flour, natural rubber latex, and certain reactive chemicals are commonly associated with work-related asthma. When recognized, these factors can be controlled, dropping the risk of disease.
An interesting theory for asthma occurrence is the hygiene hypothesis. It suggests that the rise in the prevalence of allergies and asthma is a direct and unintended result of the success of modern hygienic practices in preventing childhood infections. Studies have shown repeatedly that children coming from environments expected to be less hygienic (e.g. families from low socio-economic strata with many children) tended to result in lower incidences of asthma and allergic diseases.
These may range from mild, moderate to severe. Typically these are:
Shortness of breath on exertion or breathlessness even at rest depending on the severity.
Coughing during night and a chronic ‘throat clearing’ type of cough.
Feeling of tightness in the chest.
A respiratory wheeze (a continuous whistling sound) occurs ranging from moderate to loud.
The respiratory rate is increased along with a rapid heart rate.
Prolonged expiration is seen and a coarse rattling (rhonchus) lung sounds are audible through a stethoscope.
The symptoms may be acute or chronic. In severe cases the patient may become blue due to lack of oxygen, may complain chest pain and may also become unconscious.
Asthma can be diagnosed based on clinical history, physical examination and improvement of symptoms on inhalation of broncho dilating medication. A chest x-ray or CT scan may be required to exclude the possibility of other lung diseases. Lung function tests may be done to confirm the clinical diagnosis. Peak flow meter test is to find out the severity of the disease. Capnography, pulse oximetry and breath test are some more tests to find out severity of the disease.
Asthma treatment includes treatment for prevention, relief, and treatment in emergency. In the conventional treatment the symptoms are treated by controlling the inflammation of bronchial airways. Inhalable corticosteroids are the mainstay of Asthma management. This technique makes it easy to distribute the medicine where it is needed and this has no side effects. Mild asthma can be treated with inhalers but the severe, chronic or the recurrent asthma needs treatment with anti-inflammatory drugs, inhalable corticosteroids and bronchodilators.
Severe asthma attacks require hospitalization. Inhalers, asthma spacers and nebulizers are some of the devices used in treatment of asthma. Treatment to relive the symptoms includes use of selective Beta2 adrenergic agonists, less selective adrenergic agonists, anticholinergics and glucocorticoids.
Other medications include leukotriene modifiers, mast cell stabilizers, antimuscarinics/ anticolinergics or methylxanthines helps in preventing the asthma attack. The other therapies are hyposensitization, use of IgE blockers or medications to treat gastro esophageal reflux disease. Trigger identification and avoidance is also a very important aspect of overall asthma management.
Rate of mortality due to asthma is very low so prognosis of asthma is good. About half the number of children diagnosed with asthma recover from the disease in a decade’s time. Some may have mild symptoms later in life but that can be managed using corticosteroids.
If the symptoms of asthma get worse than usual then it is called as asthma attack. In this situation the vital organs of the body that get supply of oxygen and as a result appear blue. If the symptoms of asthma are severe than normally experienced, immediately contact your doctor.
