Asthma is a chronic lung condition characterized by difficulty in breathing. People with asthma have extra sensitive or hyperresponsive airways. The airways react by narrowing or obstructing when they become irritated. This makes it difficult for the air to move in and out. This narrowing or obstruction can cause one or a combination of symptoms such as wheezing, coughing, shortness of breath and chest tightness.When is Asthma really bad?
1. If the wheezing was audible periodically suddenly stops and the patient is still feeling severely out of breath.
2. If the muscles of the neck and those above the collar bone stand out in effort with every act of respiration.
3. If the attack is continuing unabated for several hours or even days with no symptom free periods in between.
Asthma attack
Asthma attacks occur when the bronchi and bronchioles become inflamed, reducing the space through which air can travel through the lungs. This causes the asthmatic to work harder to move air in and out of the lungs. Asthma attacks usually begin with mild chest pressure and a dry cough. As an attack intensifies, wheezing develops and increases in pitch; breathing becomes difficult; and coughing produces thick, stringy mucus. As the airway inflammation prevents some of the oxygen-rich air from reaching the alveoli, the cells of the body start to burn oxygen at a higher rate, actually increasing the body’s demand for oxygen. The frequency of asthma attacks varies considerably among asthma suffers. Some people have daily attacks, while others can go months or even years without having an attack.
Inflammation of the airway occurs when an irritant—such as pet hair or cigarette smoke—comes into contact with the airway walls. Upon detecting the irritant as a harmful invader, the body’s immune system sends special cells known as mast cells to the site of irritation, in this case the airway walls. The mast cells release histamine, a chemical that causes swelling and redness in a process called the inflammatory response. Histamine also causes bronchospasms, in which the muscles lining the airway walls contract repeatedly, causing the airways to narrow even more. In addition, cells that lubricate the airways with mucus—called goblet cells—overreact to the inflammatory response by secreting too much mucus. This mucus clogs the bronchioles, resulting in wheezing and coughing. Causes...
Asthma attacks are caused by airway hyperresponsiveness—that is, an overreaction of the bronchi and bronchioles to various environmental and physiological stimuli, known as triggers. The most common causes of asthma attacks are extremely small and lightweight particles transported through the air and inhaled into the lungs. When they enter the airways, these particles, known as environmental triggers, cause an inflammatory response in the airway walls, resulting in an asthma attack.
For some people the environmental triggers are allergens. Allergens are usually natural substances, such as plant pollen and mold spores, animal dander (tiny pieces of animal hair and skin), and fecal material from dust mites and cockroaches. Allergens produce an exaggerated response of the immune system in which a specific antibody, immunoglobulin E, initiates the inflammatory response. These same allergens may cause little or no reaction in nonallergic people.
Asthma also occurs in people who do not have allergies. In these people, chemical irritants trigger an inflammatory response that is initiated in a different way than in allergen-triggered asthma. For example, some people are sensitive to certain common chemical irritants, such as perfume, hairspray, cosmetics, and household cleaners. Other chemical irritants include industrial chemicals and plastics, as well as many forms of air pollution, such as exposure to high levels of ozone, car exhaust, wood smoke, and sulfur dioxide. Current research seeks to determine whether indoor pollutants also contribute to the development of asthma.
Not all triggers are environmental. Aggravations from within the body are known as physiological triggers and include exercise and infections, such as the common cold. Sometimes substances that asthmatics eat or drink bring on attacks. Chemicals found in food or medicine—such as food sulfites found in beer and wine—and medications such as aspirin and ibuprofen are especially problematic for many asthma sufferers. Intense emotion, such as crying, shouting, or laughing, may provoke hyperventilation, a rapid inhalation of oxygen that causes the airway to narrow. In asthmatics, hyperventilation often results in an attack. Many asthmatics are especially sensitive to physical exercise in cold weather.
Research suggests that genetic factors may increase the risk of developing the disorder. Children with a family history of asthma are more likely to develop asthma than other children. Despite this apparent genetic link, many people without a family history of asthma develop the disorder, and scientists continue to investigate additional causes.
