Asthma is chronic inflammatory disease of the airways. In those susceptible to asthma, this inflammation causes the airways to narrow periodically. During asthma attacks (exacerbations of asthma), the smooth muscle cells in the bronchi constrict, and the airways become inflamed and swollen. This, in turn, produces wheezing and breathlessness, sometimes to the point where the patient gasps for air. Obstruction to air flow either stops spontaneously or responds to a wide range of treatments, but continuing inflammation makes the airways hyper-responsive to stimuli such as cold air, exercise, dust mites, pollutants in the air, and even stress and anxiety.
Asthma usually begins in childhood or adolescence, but it also may first appear during adult years. While the symptoms may be similar, certain important aspects of asthma are different in children and adults.
Child-onset asthma
When asthma does begin in childhood, it often does so in a child who is likely, for genetic reasons, to become sensitized to common "allergens" in the environment (atopic person). When these children are exposed to house-dust mites, animal proteins, fungi, or other potential allergens, they produce a type of antibody that is intended to engulf and destroy the foreign materials. This has the effect of making the airway cells sensitive to particular materials. Further exposure can lead rapidly to an asthmatic response. This condition of atopy is present in at least one-third and as many as half of the general population. When an infant or young child wheezes during viral infections, the presence of allergy (in the child itself or a close relative) is a clue that asthma may well continue throughout childhood.
Adult-onset asthma
Allergenic materials may also play a role when adults become asthmatic. Asthma can actually start at any age and in a wide variety of situations. Many adults who are not allergic do have such conditions as sinusitis or nasal polyps, or they may be sensitive to aspirin and related drugs. Another major source of adult asthma is exposure at work to animal products, certain forms of plastic, wood dust, or metals.
SYMPTOMS
Because of the spectrum of severity within asthma, some people with asthma only rarely experience symptoms, usually in response to triggers, where as other more severe cases may have marked airflow obstruction at all times.
Asthma exists in two states: the steady-state of chronic asthma, and the acute state of an acute asthma exacerbation. The symptoms are different depending on what state the patient is in.
Common symptoms of asthma in a steady-state include: nighttime coughing, shortness of breath with exertion but no dyspnea at rest, a chronic 'throat-clearing' type cough, and complaints of a tight feeling in the chest. Severity often correlates to an increase in symptoms. Symptoms can worsen gradually and rather insidiously, up to the point of an acute exacerbation of asthma. It is a common misconception that all people with asthma wheeze—some never wheeze, and their disease may be confused with another Chronic obstructive pulmonary disease such as emphysema or chronic bronchitis.
An acute exacerbation of asthma is commonly referred to as an asthma attack. The cardinal symptoms of an attack are shortness of breath (dyspnea), wheezing and chest tightness. Although the former is "often regarded as the sine qua non of asthma, some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard. When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, breathing becomes difficult, and wheezing occurs (primarily upon expiration, but can be in both respiratory phases). It is important to note inspiratory stridor without expiratory wheeze however, as an upper airway obstruction may manifest with symptoms similar to an acute exacerbation of asthma, with stridor instead of wheezing, and will remain unresponsive to bronchodilators.
TREATMENT
The goal of treatment is to avoid the substances that trigger your symptoms and to control airway inflammation. The patient and the doctor should work together as a team to develop and carry out a plan for eliminating asthma triggers and monitoring symptoms.
There are two basic kinds of medication for the treatment of asthma:
- Long-acting medications to prevent attacks
- Quick-relief medications for use during attacks
Long-term control medications are used on a regular basis to prevent attacks, not to treat them. Such medicines include:
- Inhaled corticosteroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent inflammation
- Leukotriene inhibitors (such as Singulair and Accolate)
- Long-acting bronchodilators (such as Serevent) help open airways
- Omilizumab (Xolair), which blocks a pathway that the immune system uses to trigger asthma symptoms
- Cromolyn sodium (Intal) or nedocromil sodium (Tilade)
- Aminophylline or theophylline (not used as frequently as in the past)
- Sometimes a single medication that combines steroids and bronchodilators are used (Advair, Symbicort)
Quick relief, or rescue, medications are used to relieve symptoms during an attack. These include:
- Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, Xopenex, and others
- Corticosteroids, such as methylprednisolone, may be given directly into a vein (intravenously), during a severe attack, along with other inhaled medications
People with mild asthma (infrequent attacks) may use quick relief medication as needed. Those with persistent asthma should take control medications on a regular basis to prevent symptoms. A severe asthma attack requires a check up by a doctor and, possibly, a hospital stay, oxygen, and medications through a vein (IV).
A peak flow meter is a simple device to measure how quickly the patient can move air out of yhis/her lungs. It can help him/her see if an attack is coming, sometimes even before any symptoms appear. Peak flow measurements can help show when medication is needed, or other action needs to be taken. Peak flow values of 50-80% of a specific person's best results are a sign of a moderate asthma attack, while values below 50% are a sign of a severe attack.
PREVENTION
Asthma symptoms can be substantially reduced by avoiding known triggers and substances that irritate the airways.
Bedding can be covered with "allergy proof" casings to reduce exposure to dust mites. Removing carpets from bedrooms and vacuuming regularly is also helpful. Detergents and cleaning materials in the home should be unscented.
Keeping humidity levels low and fixing leaks can reduce growth of organisms such as mold. Keep the house clean and keep food in containers and out of bedrooms -- this helps reduce the possibility of cockroaches, which can trigger asthma attacks in some people.
If a person is allergic to an animal that cannot be removed from the home, the animal should be kept out of the patient's bedroom. Filtering material can be placed over the heating outlets to trap animal dander.
Eliminating tobacco smoke from the home is the single most important thing a family can do to help a child with asthma. Smoking outside the house is not enough. Family members and visitors who smoke outside carry smoke residue inside on their clothes and hair -- this can trigger asthma symptoms.
Persons with asthma should also avoid air pollution, industrial dusts, and other irritating fumes, as much as possible.
