Asthma

MEDICAL ANIMATION TRANSCRIPT: Asthma is a chronic inflammatory disease that obstructs airflow in and out of the bronchial tubes. Normally, as the diaphragm contracts and relaxes, air moves freely in and out of the trachea and bronchi to the bronchioles and then to the alveoli, where gas exchange takes place. During this process, carbon dioxide will diffuse out of the bloodstream into the alveolus, while oxygen will diffuse from the alveolus into the bloodstream. Smooth muscle in the bronchial walls is controlled by the autonomic nervous system. Sympathetic stimulation relaxes smooth muscle and produces bronchodilation when the air is warm, moist, and free of irritants. Parasympathetic stimulation contracts smooth muscle and produces bronchoconstriction when the air is cold, dry, or contains irritants. People with asthma have chronically inflamed and swollen airways that are hyperreactive to irritants that can trigger an asthma attack. Asthma triggers include outdoor irritants and allergens, such as pollen, smoke, pollution, and cold weather; indoor irritants and allergens, such as mold, pet dander, dust mites, and cockroach droppings; food allergens, such as fish, shellfish, eggs, peanuts, and soy; physiological conditions, such as respiratory infections, stress and strong emotions, and exercise. During an asthma attack, these triggers can induce mast cells and leukocytes to release chemical substances, such as histamine, kinins, prostaglandins, and leukotrienes. These substances are chemical mediators of inflammation that can precipitate a bronchospasm. Suddenly, the bronchial smooth muscle tightens, and the bronchial wall becomes more swollen. Goblet cells in the mucosa produce thicker mucus, further obstructing the airway. This combination of factors slows normal gas exchange. The symptoms of a bronchospasm include coughing, wheezing, shortness of breath, and chest tightness. Medicines that treat asthma affect the inflammation of the airway wall, the constriction of the bronchial muscles, or mucus secretion. The most important asthma medications are long-acting anti-inflammatory drugs, such as corticosteroids, leukotriene inhibitors, and cromolyn sodium. These drugs keep asthma under control by preventing or reducing inflammation of the bronchial wall. This makes the airways less sensitive to bronchospasm triggers. Regular use of maintenance medications makes it less likely that an asthma flare-up will take place. Bronchodilators are either quick relief rescue medications, such as short-acting beta-agonists, or long-acting maintenance medications, such as theophylline and anticholinergics. These drugs cause the bronchial smooth muscle to relax quickly or gradually over a longer period of time. Regular use of long-acting maintenance medication is critical in keeping your airways open and less inflamed. This reduces the likelihood of asthma flare-ups. When flare-ups do happen, it is important for patients to work with their licensed healthcare professional to develop an action plan for the correct use of short-acting rescue medication. Rescue medication opens airways quickly, providing symptom relief within minutes.