Asthma is a common condition that can occasionally threaten life.

ASTHMA is common worldwide. It is a complex condition in which there is obstruction of the airflow in the lungs, increased sensitivity and responsiveness of the bronchi, and an underlying inflammation, which are recurrent.

The increased bronchial irritation leads to inflammation and swelling, which causes narrowing of the muscles surrounding the bronchi. This leads to recurrent coughing, wheezing, breathlessness and tightness in the chest. The airflow obstruction is usually widespread and variable but is often reversible, either spontaneously or with treatment.

Airflow interrupted: A doctor attending to a patient who had an asthma attack. Asthmatic attacks can be mild, moderate, or severe. The mild attacks can be treated on an outpatient basis. The severe attacks may require hospitalisation as they may be potentially life-threatening.

The severity of the symptoms is variable, even in the same person. If the asthma is longstanding (chronic), it may result in irreversible obstruction of the airways, a condition called chronic obstructive airway disease. Asthmatic attacks can be mild, moderate, or severe. The mild attacks can be treated on an outpatient basis. The severe attacks may require hospitalisation as they may be potentially life-threatening.

The National Health and Morbidity Survey 2006 reported that 4.3% of adults had asthma. It was more common in Indians (6.7%) and Malays (5.57%). Other risk factors included lower income groups, lower education level, and unemployment.

There was no difference in its prevalence between males and females, and between those living in rural and urban areas. About 32.11% of asthmatics reported school/work day loss with a mean of six days, 21% reported limited sleep, 16.88% had limitation in normal physical exertion, and 15.63% had limitation in keeping up with housekeeping chores.

The overall prevalence in children was 7.14%, with the highest among Malays (8.8%) and Indians (7.35%). About 82.06% of the asthmatics attended clinics due to attacks in the preceding year, 32.22% attended hospital emergency departments, and 14.29% were hospitalised.

Causes

The genesis of asthma is complex. It is believed to result from an interaction between genetic and environmental factors. Asthma often occurs in families. It has an inherited component, but the genetics involved are complex. The development of a person’s immunity in early life affects the body’s immune response to infections. When the immune response is dominated by certain immune cells, it predisposes the person to allergic conditions and asthma.

There are two main environmental factors that affect the development, persistence, and, possibly, the severity of asthma. They are airborne allergens and viral respiratory infections. Other environmental factors are thought to be associated with the onset of asthma, but the jury is still out on these factors.

There are several conditions that are associated with the development of asthma, viz: a family history of asthma, or other related allergic conditions like eczema, allergic rhinitis, or allergic conjunctivitis; history of bronchiolitis, a lung infection in childhood; exposure to tobacco smoke in childhood, especially if there was maternal smoking during pregnancy; premature birth; and low birth weight.

The triggers of an asthmatic attack include airborne allergens, e.g. house dust mites, animal fur, pollen; respiratory infections which are usually viral, although bacterial, fungal, and parasitic infections may be involved; airborne irritants, e.g. tobacco smoke, chemical fumes, and atmospheric pollutants; medicines, e.g. nonsteroid anti-inflammatory drugs (NSAIDs); emotional factors, e.g. stress; foods that contain sulphites, e.g. wine, shrimp, and many processed foods; and weather conditions, e.g. cold weather.

Clinical features

A diagnosis of asthma is considered when the following clinical features are present:

> Wheezing, which are high-pitched whistling sounds when breathing out, particularly in children

> History of recurrent wheeze, difficulty in breathing or tightness in the chest, or cough that is worse at night

> Coughing, especially at night

> The symptoms occur or are worsened by airborne allergens, respiratory infections, airborne irritants, emotional factors, weather changes, or exercise

> The symptoms occur or are worse at night, awaking the person from sleep

The severity and duration of the symptoms are frequently unpredictable and variable. They are occasionally worse at night or with exercise. Severe asthmatic attacks take up to 36 hours to develop.

The doctor will take a history and perform a physical examination, which is focused on the upper respiratory tract, lungs, and skin.

Spirometry is an objective test used to establish the diagnosis of asthma. It is done to check whether there is obstruction of the airflow and assess the reversibility of the condition in all patients aged five years and above.

Additional investigations are usually not necessary but may be done if other diagnoses are suspected. They include lung function tests, imaging tests, blood tests, etc.

Asthma can lead to serious respiratory complications, which are life-threatening. They include pneumonia, which is an infection of the lungs; collapse of the lung or part of it; respiratory failure, which is a situation in which the blood oxygen levels are very low or the blood carbon dioxide levels are very high, both of which are dangerous; and status asthmaticus, i.e. severe attacks that are not responsive to treatment.

Management

Although there is no cure for asthma, there are treatments available that are of value in the management of the condition.

The management goals are assessment and monitoring the severity of asthma; patient and parental education in the provision of care; control of environmental factors and associated conditions; and prescription of medicines to treat the condition.

When a diagnosis of asthma is confirmed, an assessment will be made of the pattern and severity of the symptoms, identification of possible triggers, and treatment.

The patient will be assisted in putting together an asthma plan. This involves keeping a record of symptoms, the recognition of worsening symptoms and taking appropriate measures, and the provision of information about the medicines prescribed and on what needs to be done when there is an asthma attack. A flow meter may have to be obtained to monitor the symptoms and the effects of treatment.

The treatment of asthma follows a step-wise approach in which the treatment prescribed will be in accordance with the severity of the symptoms. A patient moves up the steps if the symptoms become worse, and down the steps when they are better.

The goal is to find the lowest possible step that will successfully manage a patient’s asthma.

The objectives of treatment are twofold, i.e. to reduce harm and risk. The former include the prevention of chronic and trying symptoms, maintain near normal lung function, and maintain normal daily activities.

The latter include prevention of recurrent attacks and minimising the need for visits to the emergency department or hospitalisation, preventing loss of lung function, and providing medicines with minimal or no side effects.

The medicines used to treat asthma include beta 2 agonists, corticosteroids, leukotriene receptor antagonists, and theophyllines, depending on the step the patient is at. For example, short acting beta 2 agonists are used at the first step and long acting or slow release ones at a higher step; inhaled corticosteroids are used at a step higher than long acting beta 2 agonists. Oral corticosteroids are used at the highest step.

There are side effects if oral corticosteroids are taken for more than three months, or often, e.g. three or four courses per year. The side effects include high blood pressure, diabetes, weight gain, osteoporosis, and muscular weakness.

Traditional and complementary medicines have been promoted by certain quarters for the treatment of asthma. They include acupuncture, ionisers, homeopathy, and supplements. There is no evidence that any of these modalities are effective.

Asthmatic attacks can be prevented by a combination of medicines, adherence to lifestyle changes, and identification and avoidance of triggers.

The lifestyle changes include smoking cessation, avoidance of secondhand smoke, and maintaining a healthy weight by taking healthy foods and regular exercise. As allergic rhinitis and sinusitis are known to aggravate asthma, it is important that they are treated early. Although the asthma may not get better, the treatment of either condition will prevent the asthma from worsening.

Source: Dr Milton Lum