Asthma can broadly be divided into extrinsic (allergic), intrinsic, drug-induced, exercise-induced, and infectious types. Each type is triggered by different stimuli, but all will result in an inflammatory response and bronchial constriction.
Demonstration of reversible airway obstruction is a clinical criterion for asthma.
- Extrinsic asthma is triggered by allergens, such as dust, mold, house mites, animal dander, and saliva.
- Intrinsic asthma may be triggered by stress.
- Drug-induced asthma can be triggered by aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), angiotensin converting enzyme (ACE) inhibitors, nuts, berries, and sodium metabisulfate, which is used as a food preservative.
- Exercise-induced asthma may be triggered by exertion and cold air.
- Infectious asthma can be triggered by bacterial, viral, and fungal infections.
The treatment goal for asthma therapy is to control symptoms with the least amount and number of medications. While control of inflammation is a long-term aim, bronchodilation will achieve immediate relief.
Mild to moderate asthma attacks can be treated with nebulized bronchodilators.
Acute exacerbations may require injection with 1:1,000 solution of epinephrine.
If relief cannot be achieved after a second dose of epinephrine, the patient needs emergent medical attention.
The types of medications will indicate severity, suggest if acute exacerbations have occurred, and indicate the need for glucocorticosteroid replacement therapy.
Corticosteroids - anti-inflammatory medication.
Cromolyn sodium and nedocromil - used to stabilize mast cells.
Immunomodulators - Omalizumab, a monoclonal antibody used to prevent binding of IgE to basophils and mast cells.
Leukotrine modifiers - Montelukast and zafirlukast,used to reduce inflammatory response.
Long-acting β2 agonists (LABA) - Salmeterol and formoterol, used to achieve bronchodilation.
Methylxanthines - Theophylline, used to achieve bronchodilation.
Anticholinergics - used to inhibit muscarinic cholinergic receptors and reduce intrinsic vagal tone of the airway.
Short-acting β2 agonists (SABA) - Albuterol, levabuterol, and pirbuterol, used to achieve bronchodilation.
Systemic corticosteroids - used to speed recovery and prevent recurrence of exacerbations.