Asthma

Asthma is a worldwide public health problem affecting people living in both developed as well as developing countries. According to the World Health Organisation, 15 to 20 million people in India are affected by asthma, and it is common in 10% to 15% of children in the age group of 5-11 years. Asthma affects all age groups and can disrupt the day to day activities of these people.

What is Asthma?

Asthma is a long-term (chronic) inflammatory respiratory condition that results from an increased sensitivity of the air passages in the lungs to various stimulants or allergens. When this inflammation persists for a long period, it leads to swelling. Also, a sticky mucous is released into the air passages. Continued or frequent exposure to the allergens causes further constriction of the muscles. Swelling, mucus in the air passages, and constriction of the muscles of air passages leads to narrowing of the air passages and results in shortness of breath, chest tightness, cough, and wheezing. Acute asthmatic attacks (flare-ups or exacerbations) appear when the airways are inflamed upon exposure to an allergen. The symptoms sometimes are mild and resolve with minimal treatment. However, when they are severe, you may require an emergency hospitalisation.

Asthma is divided into different types depending on the causes and the accompanying symptoms. These include:

• Allergic Asthma
  This type is commonly seen in babies. Children develop symptoms in response to indoor allergic stimulants, such as dust, mould, dust-mites, fur and feathers of pets, and cockroach droppings. Adults with allergic asthma are sensitive to pollens from trees and weeds, pollution, tobacco smoke, a strong smell of perfumes or paints, and dust in addition to the above-mentioned allergens. Children with allergic asthma also have other allergic symptoms, such as irritation in the nose, runny nose, and redness and itching in the eyes.
   
• Exercise-induced Asthma
  In some people, asthma is triggered by physical exertion such as exercise. Wheezing and breathlessness develop after 5 to 20 minutes of exercise and decrease on stopping it. The use of bronchodilators before exercise helps in preventing exercise-induced asthma.
   
• Cough-variant Asthma
  A dry cough without mucus production is the main symptom of cough-variant asthma. It ups in children and adults after exercise or upon exposure to environmental allergens, such as smoke, dust, and cold air. Occasionally, severe coughing can occur at night and disturb sleep. The risk of cough-variant asthma increases in people who have sinusitis. Certain medicines, such as beta-blockers, prescribed for high blood pressure, heart conditions, glaucoma (eye problems), and migraine, usually cause cough-variant asthma. Aspirin is another medicine that causes cough-variant asthma.
   
• Nocturnal Asthma
  Some people experience wheezing and breathlessness during sleep at night. The probable causes include high allergen exposure at night, accumulation of mucus in sinuses or post-nasal drip, night secretion of certain hormones, relaxed airways narrowing at night, cooling of airways due decreased humidity and moisture in the airways, and sleeping position of lying down. It is observed that deaths due to asthma occur maximally at night.
   
• Occupational Asthma
  Asthma occurring in those due to exposure to allergens at the workplace, for example:
  • Workers wearing latex gloves develop asthma.
  • Exposure to chemicals, such as ammonia, paints (shellac or lacquer), dyes, cotton, hemp dust (textile industry), grain dust, and coffee beans.
  • Soldering fumes of metals, such as chromium and platinum. These allergens induce asthma either due to irritation or allergic reaction in the airways or by the release of a chemical called histamine in the lungs.

The severity of asthma is divided into different stages that help the doctor to start an appropriate line of treatment.

• Intermittent
  There are very few symptoms for a maximum of 2 days a week with minor to severe flare-ups (acute exacerbations) at night. Usually, these flare-ups are not experienced more than twice in a month.

• Mild persistent
  Affects normal activities with symptoms more than twice a week and acute flare-ups more than twice in a month at night. Lung function tests reveal 80% of normal range values.

• Moderate persistent
  Asthma symptoms occur daily with severe wheezing. Flare-ups (acute exacerbations) occur more than once a week at night and last for longer periods. Lung function tests reveal 60% to 80% of normal values.

• Severe persistent
  It is the least encountered level of asthma. Symptoms of very severe intensity occurring daily at night. Lung function tests reveal less than 60% of normal values.

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Symptoms of asthma chiefly arise due to narrowing of the air passages in the lungs. These include;

• Breathlessness or Shortness of Breath
  People with asthma usually experience breathlessness, feeling out of breath or gasping for breath, especially during flare-ups of asthma.
• Wheezing
  This is a high-pitched sound caused due to resistance to the airflow through narrow air passages. In the mild form of asthma, wheezing usually occurs while a person breathes out. In the severe form of asthma, wheezing is also present when a person breathes in. In very severe and intense cases, there is so much obstruction and narrowing of air passages that wheezing is completely absent.
  Wheezing is present in other health problems, such as cystic fibrosis, heart failure, and vocal cord dysfunction. Hence, it is essential to diagnose asthma through different investigations.
• Cough
  Coughing is one of the main symptoms of asthma, especially in exercise-induced asthma and nocturnal asthma. It is dry and non-productive. 
• Chest Tightness
  A feeling of tightness in the chest or pain in the chest is sometimes the only presenting symptom of asthma, particularly in nocturnal asthma and exercise-induced asthma.

Causes

There are no specific causes associated with asthma. However, research studies have shown that people suffering from allergic conditions are more likely to suffer from asthma due to an increased sensitivity of the airways to the stimulants.

• Genetic link and inheritance are strongly associated in those who have asthma.
• Certain viral infections and other respiratory infections in the childhood in association with a positive family history of asthma are chief indicators of asthma.
• Asthma is mainly caused by exposure to allergens, such as dust, pollution, smoke, strong odour, pollens, blood pressure medicines, aspirin, and sulphites in food and drinks.

Risk factors

Although asthma affects all age groups, children are more prone to it. 

• Children with a wheezing problem and recurrent respiratory infections (such as pneumonia, bronchiolitis) are at a higher risk of developing asthma after 6 years. 
• Children suffering from different allergies or skin conditions, such as eczema, or having a family history of asthma carry a risk of asthma to a significant extent.
• In children, boys suffer more than girls do, whereas in the case of adults, women are at higher risk of asthma than are men.
• Asthma and different other forms of allergies usually co-exist in most people.
• People who work in places where there is high exposure to allergens are at high risk of occupational asthma.

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Although It is difficult to prevent asthma completely, some measures can help in keeping the disease under control.

• Know your triggers. Information about the triggering factors helps in avoiding exposure to them.
• Monitor your symptoms of asthma with the help of your doctor and follow regular health check-ups.
• Although exercise triggers asthma in many people, do not stop simple exercises such as walking. If you want to opt for more intense exercises, ask your doctor for medicines that can help in preventing exercise-induced asthma.
• Take medicines incorrect doses as prescribed by the doctor.
• Maintain and follow an asthma action plan for the use of medicines at the right time to control the acute symptoms.

Various tests are used for diagnosing asthma. Few tests among many others are commonly conducted in daily practice to diagnose asthma. However, breathing tests are essential components of the diagnostic tests of asthma.

• Medical history
  Detailed History of symptoms, family history, and clinical examination help in the diagnosis of asthma before investigations.
• Pulmonary Function Tests or Lung Function Tests
  • A spirometry test is used to analyse the lung size and the rate of airflow in the lungs. This test is useful in evaluating the beneficial effects of the treatment given for asthma.
  • Broncho-provocation test consists of exposure of lung air passages to different agents and evaluation of the bronchial response (constriction of air passages) to them. These agents include methacholine, cold or dry air, exercise, inhalation of allergen, and mannitol.
• Peak Flow Monitoring
  It is the most commonly used monitoring device to assess the airflow in response to the therapy used to treat asthma.
• Fractional Exhaled Nitric Oxide Test
  This test measures nitric oxide exhaled in your breath. This helps to analyse the amount of inflammation in the airways caused due to an allergic reaction in response to allergens.

• Other tests
  These include:

  • Chest X-ray.
  • X-ray for sinuses.
  • Tests for acid-reflux.
  • Allergy tests, such as skin prick test, intradermal skin test, immunoglobulin E (IgE)-specific blood test, and skin patch test.

The treatment is aimed at providing immediate relief from an acute attack and providing a long-term management that prevents frequent acute attacks.

Quick Relief (Reliever Medications)

These are also known as rescue medications and are used to provide instant relief from the distressing symptoms of acute episodes of asthma. Doctors commonly advise these to be taken before exercising, as an acute flare of symptoms commonly occurs after exercises (exercise-induced asthma), such as running or cold weather activities (skiing, ice skating, ice hockey). Quick-relief medications rescue from the distress by quickly opening the constricted airways by relaxing the smooth muscles in and around them.

Short-acting beta-agonists are the first choice of rescue medicines to give quick relief from the discomforting symptoms of acute asthma attack. These are inhalable medicines that cause dilatation of airways (bronchodilation) instantly. Doctors prescribe albuterol, levalbuterol, and pirbuterol. Medicines of long-term asthma management should not be stopped while you are taking reliever medicines. It essential to notify the doctor if you need to take quick-relief medicines for more than twice a week.

Long-term Control (Controller Medications)

• Inhaled corticosteroids
  These are the first option for the long-term treatment of asthma. They reduce the inflammation in the airways and consequently the swelling that narrows the air passages (e.g., fluticasone, budesonide, mometasone, beclomethasone, and prednisolone).
• Inhaled corticosteroids and long-acting beta-agonists 
  Long-acting beta-agonists (LABA) relax the smooth muscles and keep the airways open. Sometimes, they are used in treating nocturnal asthma and exercise-induced asthma. However, the doctor will always prescribe LABA in combination with an inhaled steroid for the long-term treatment of asthma. This combination is also used when short-acting beta-agonists and inhaled steroids fail to relieve symptoms of an acute attack. Fluticasone and salmeterol, fluticasone and vilanterol, budesonide and formoterol, are some examples of the combination.
• Long-acting anticholinergics
  These are inhaled medicines and are used as maintenance medicines to keep the smooth muscles in the airways relaxed. These include tiotropium and ipratropium. Doctors sometimes also prescribe a combination of two anti-cholinergic medicines to increase the effectiveness of the medicines.
• Methylxanthines
  Methylxanthines such as theophylline, are used for preventing episodes of nocturnal asthma.
• Leukotriene receptor antagonists or leukotriene modifiers
  These are oral medications that help in relieving bronchospasm, inflammation, and swelling in the airways. These include montelukast and zafirlukast.
• Mast-cell stabilisers
  They help in decreasing the inflammation and thereby control the acute asthma episodes due to exposure to cold air and exercise (e.g., cromolyn sodium).
• Immunotherapy or immunomodulators
  These are injectable medicines that help in preventing asthma due to exposure to allergens, such as pollens, moulds, dust mites, and dander from animals. Omalizumab consists of anti-IgE monoclonal antibodies that control the body’s allergic reaction to an allergen. Other examples are reslizumab and benralizumab.
• Bronchial thermoplasty
  This is a recent FDA-approved procedure for treating a severe form of asthma in adults who do not benefit from the medical treatment. Controlled radio waves are delivered into the air passages to generate heat energy and destroy the smooth muscles in the airways. This reduces constriction of airways due to modification in the immune system caused by the destruction of smooth muscles in the airways.

Lifestyle management

Asthma remains an incurable disease with a major cause of anxiety among those who have it as there is an irregularity in the episodes of breathlessness and distressing symptoms of tightness in chest and shortness of breath. Therefore, the normal routine of people with asthma can get disrupted leading to a decrease in the work output, and a significant financial loss. The aim of the management, therefore, is to reduce the intensity and frequency of acute episodes and prevent future adverse effects, such as lung damage, infections, or death.

• Self-care is the chief component in the management of asthma. Having an adequate understanding of the disease and information about the triggers helps in preventing the acute attacks. Knowledge about how to effectively control an acute attack (such as the use of flow charts of medicines) helps people with asthma to deal with an emergency effectively. Also, maintaining an action plan ready for your child after discussing with the doctor, which can be executed in situations of acute episodes is also very helpful.
• Anxiety is a behavioural change that is consistently observed in those diagnosed with asthma. It is an important contributing factor triggering the acute episodes of asthma. Breathing exercises, meditation, yoga, and other mind relaxing techniques help in the long-term management by overcoming fear and anxiety related to asthma. Training in various breathing techniques, such as breathing–control techniques, help in normalising the breathing patterns and overcome the psychological stress of unpredictable acute episodes of asthma.
• Moderate regular exercises, such as walking, complete avoidance of smoking, and healthy nutritious dietary habits, are few other lifestyle moderation practices that can be incorporated in the management program of asthma.

Prognosis

Different research studies have shown that the outcome of asthma treatment depends on the severity of the disease. The chances of milder symptoms going into remission are much more than the asthma symptoms of severe form. Frequent hospitalisations and permanent lung damage are commonly associated with severe acute exacerbation episodes of asthma and are the chief reasons for death. Inhaled steroids and bronchodilators play a key role in minimising lung damage and chances of death.

Complications

Reduced efficiency at workplace, frequent absenteeism at school, and disturbance in day-to-day activities are common complications encountered in those suffering from asthma. Repeated acute flare-ups can result in permanent narrowing of air passages and lung damage. There are high-risk side effects of medications (corticosteroids) used in the long-term management of asthma, such as growth retardation in children and decrease in the density of bones. Death is an extremely rare complication of asthma.