Asthma is a condition whereby the airways are inflamed and hyperresponsive to various stimuli. This results in constriction of the airways, often producing characteristic wheezing sounds, and excessive mucous secretion adding to airflow limitations.
The symptoms of asthma, including wheezing, shortness of breath, atypical chest pain and cough can be more prominent at night and in the early morning hours but can also occur with exposure to various allergens, or triggers, that start the inflammation cascade. This reaction includes many types of cells, including eosinophils that release chemicals that cause bronchoconstriction or narrowing of the airways. This is also the stimulus for excessive mucous production that can cause blockage of the smaller airways resulting in shortness of breath and cough.
The diagnosis of asthma is based on a complete history and physical exam, along with a chest x-ray and pulmonary function testing. Occasionally, testing with Methacholine inhalation will stimulate the asthma response and confirm the diagnosis. There are several diagnostic subcategories including Aspirin-induced asthma, exercise-induced asthma, allergic bronchopulmonary aspergillosis, and occupational asthma.
The treatment of asthma involves patient education, control of the environment, and various drug therapies that interrupt the release of chemicals that lead to airway inflammation. Of these, patient education is pivotal because recognizing and treating an asthma attack early on can prevent hospitalization and serious morbidity and mortality. Drug therapy is tailored to each patient based on their clinical reaction to various environmental triggers and can include “controller” and “rescue” medications along with immunotherapy and occasional steroid use.
Figure A shows the location of the lungs and airways in the body. Figure B shows a cross-section of a normal airway. Figure C shows a cross-section of an airway during asthma symptoms.
Source: National Heart, Lung and Blood Institute