Asthma is a chronic inflammation of the bronchial airways that causes bronchospasm and narrowing of airways. This condition primarily affects the bronchi. According to the Global Initiative for Asthma, 300 million people are affected by this condition. The prevalence of asthma nowadays is increasing especially in children. Luckily, asthma can be treated and air obstruction caused by this condition is reversible.
Extrinsic - also called allergic asthma. This type of asthma is triggered by allergies. Usually patients who have this type of asthma have a family history of allergies. This type accounts for 90% of all asthma cases and usually develops during childhood.
Intrinsic - the other 10% of asthma cases fall under this category. The onset of intrinsic asthma usually develops after the age of 30. Some cases of this type are preceded by respiratory infections.
When a person is exposed to risk factors such as allergens and stress, airways narrow. Narrowing of airways is caused by these three factors: inflammation, bronchospasm and hyperactivity
When inflammation happens, bronchial wall thickens leading to edema and eventually a smaller passageway of air.
Bronchospasm occurs when inflamed airways react to triggers or factors leading to tightening of bronchial muscles therefore narrowing the air passageways.
Chronic exposure to these risk factors results to more inflammation and spasm leading to hyperactivity.
The airways of asthma patients are very sensitive to certain triggers also known as stimuli. In response to the exposure from different stimuli, the bronchi react by spasm followed by inflammation leading to hyperactivity. When prolonged exposure to stimuli happens, there will be more spasm, inflammation and excessive mucus production. This can lead to airway obstruction and death. Once the bronchial airways are exposed to stimuli, a re-exposure will cause a reaction leading to an attack.
The triggers of stimuli of asthma fall under two categories. These are the allergens (the specific type) and the non allergens (the non specific type). Triggers that belong to the allergen type are pollens, dust mites, insects, molds, and pets. There are also certain foods that can trigger asthma like peanuts and egg. Triggers that belong to the non allergen type are usually irritants. These factors are respiratory infections, medications, smoke, weather changes, chemicals, gases, emotional factors, and hormonal factors.
The four most common symptoms of asthma are shortness of breath especially at night, wheezing upon exhaling, coughing that worsens at night and the early morning, and chest tightness that occurs with or without the previous mentioned symptoms. The symptoms vary from person to person, and some symptoms become worse in cold weather, at night, or early morning.
GERD or Gastroesophageal Reflux Disease coexists in 80% of the people with asthma. This is due to increased lung pressures, chronic aspiration and the promotion of bronchoconstriction. Sleeping disorders and altered sleep pattern also happen to people with asthma especially those who are experiencing asthma attacks at night.
Medications for treatment of asthma are for relaxing bronchospasm and reducing inflammation. Bronchodilators and glucocorticoids are the treatments of choice for this condition. Inhaled medications (also known as metered dose inhalers) are preferred over oral medications because it acts faster in controlling attacks. Inhaled medications act directly on airway surfaces.
Beta 2 adrenergic agonist (such as salbutamol) is the first treatment of choice for asthma. It acts by relaxing the bronchial muscles and reducing asthma symptoms. Like the Beta 2 adrenergic agonist, anticholinergics are also bronchodilators used in treating asthma.
Glucocorticoids are the treatment of choice for long term control. Leukotriene antagonists (such as zafirlukast) and mast cell stabilizers (such as cromolyn sodium) are alternatives used for glucocorticoids.
Prevention should involve avoiding stimuli that trigger asthma attack. Avoiding stimuli may include lifestyle change such as quitting smoking, minimizing strenuous activities, and regular intake of medications.