The word "asthma" brings to mind different thoughts for different people. If you suffer from asthma, this word may mean not being able to breathe freely and easily. Or if you are a family member, it may mean that a loved one is uncomfortable, ill, or living a disrupted life where he or she misses school or work. Any one can feel the loss in the quality of life brought about by asthma.
Some people think of asthma as really just a "breathing problem"—it may at times cause people to see a doctor or go to the emergency room, but the symptoms usually aren't too bad. However, to physicians who treat asthma, asthma is a serious medical condition—one in which their patients have trouble breathing and that must be relieved through their patients' avoidance of the causes of their asthma or by their patients taking specific medication.
But is it an "allergic" condition? Not always, but in most patients many of the triggers for their asthma are allergic in nature. The most common include dust mites, cockroaches, molds, and pollens such as ragweed, grass and trees. Numerous scientific studies have shown that avoidance of specific allergens in patients with asthma who have been previously sensitized will result in improved asthma symptoms and decreased medication requirements.
How Is Asthma Recognized?
Medically, asthma is a name assigned to a group of symptoms that typically include shortness of breath, wheezing, coughing, and chest tightness. Symptoms can occur in various combinations (one, several, or all) and may range from mild to severe. Symptoms are usually intermittent, perhaps happening only on rare occasions but may occur seasonally or monthly, weekly, or even daily. In the most severe cases, symptoms are present continuously.
Asthmatic symptoms are usually quite variable; someone with asthma may go for periods of time without symptoms, and then suddenly have severe episodes for days at a time. The most common symptom recognized by both physicians and patients is wheezing. Wheezing is a whistling or rumbling sound that comes from the chest expiration. It may be very loud or barely audible.
The wheezing sound occurs when the bronchial tube — through which we breath — goes into spasm and narrows, causing air coming out of the lungs to set up vibrations as the air tries to squeeze through narrower airways. This narrowing of the bronchial tubes also prevents air from moving in and out of the lungs easily, which gives the feeling of shortness of breath (called dyspnea by physicians). Mucus, which normally forms in the bronchial tubes, cannot easily get cleared from the spastic and constricted bronchial tubes. The mucus accumulates and sets off a cough reflex as the body attempts to clear the extra mucus out of airways. Spasm by the bronchial tubes also triggers coughing. Unfortunately, each of these underlying changes eventually contributes to and aggravates other changes and symptoms.
Are There Different Types of Asthma?
There are various different types of asthma, some of which are difficult to readily diagnose. Further complicating accurate diagnosis is that, at times, and in certain individuals, there are very specific symptoms (or patterns of symptoms) unique to any one person.
Cough-variant asthma
Coughing can occur alone, without the other symptoms of asthma that are usually present and recognized by the physician or patient. Cough variant asthma causes great difficulty for the physician to accurately diagnose the true underlying cause of the cough as being asthma because it can be easily confused with other conditions, such as chronic bronchitis and post nasal drip due to hay fever or sinus disease. Coughing can occur day or night. Nighttime coughing is most disruptive, interfering with sleep.
Nocturnal asthma
Nocturnal or nighttime asthma may occur without any daytime symptoms recognized by the patient. This is called "nocturnal asthma." The patient may have wheezing or short breath when lying down or may not notice these symptoms until awoken by them in the middle of the night, usually between 2 and 4am. Nocturnal asthma may occur only once in a while or frequently during the week. Nighttime symptoms may also be a common problem in people who have daytime asthma as well, but then its true nature is more readily recognized. When there are no daytime symptoms to suggest asthma is an underlying cause of the nighttime cough, this type of asthma will be more difficult to recognize and usually delay proper therapy. The cause (or causes) of this phenomenon is unknown, although many possibilities are under investigation.
Exercise-induced asthma
Shortness of breath and/or wheezing occurring after strenuous exercise is called exercise-induced asthma. Although this phenomenon happens in up to 80% of people with recognized asthma, it frequently takes place as an isolated event without any other symptoms of asthma at any other time. This complicates any diagnosis of asthma as an underlying cause because frequently this form of asthma is confused with poor physical conditioning or possible heart problems. Nevertheless, asthma should always be suspected as a possible cause of exercise-induced wheezing or shortness of breath, especially when the person is otherwise healthy.
What Causes Asthma?
Up until 15 years ago, asthma was considered by physicians to be simply a spastic disease of the bronchial tubes which in turn led to all the other symptoms discussed above. Starting in the 1980s with our ever-increasing information and knowledge about asthma, bronchial tube inflammation was considered by most authorities as the basic underlying problem.
Inflammation is our body's response to foreign or toxic substances that enter or come in contact with the body. Inflammation is caused by the arrival of blood and protective cells into the area involved. When a bacterial infection occurs somewhere in our body, white blood cells blood rush to the infected site and try to either destroy the bacteria or isolate and neutralize their harmful effects.
This also happens in asthma, where the foreign agent is an allergy-causing substance (called an allergen), such as pollen, house dust mites, and animal dander. With asthma, the allergen triggers an unwanted and harmful inflammatory reaction which, like our response to an infection, signals the body to summon blood and white blood cells into the irritated area. The "inflammatory cells" produce and release chemical substances called mediators which attack the foreign agents or, in this case, the allergen. And in the process of the body trying to defend itself, some damage and changes occur in the tissues of the bronchial tubes.
This damage results in the development of easily irritated bronchial tubes, which is called hyper-responsiveness. This condition is then causes the lungs to become excessively "twitchy" and to react (or overreact) to previously non-allergic stimuli, such as cold weather, pollution, dry air, and chemical odors. The also-twitchy bronchial tubes will react by going into spasm, which leads to the symptoms of shortness of breath, coughing, wheezing, and chest tightness. This entire process is possibly reversible if caught early in its onset by establishing preventive measures or treating with appropriate medication.
In summary, we now recognize asthma as a condition which begins with inflammation of the bronchial membranes, which results in changes that bring about bronchial hyper-reactivity, which in turn cause the physical findings and symptoms of wheezing, coughing, shortness of breath, and chest tightness, i.e. the classic symptoms of asthma. By learning to recognize the underlying factors and symptoms of asthma, we as physicians and patients can more adequately control and better treat both the causes and effects of asthma.
