The faces of childhood asthma are many:
Your child who complains about shortness of breath after running. Your infant with her fourth episode of "bronchitis" this season. The child who always seems to be coughing and whose colds seem to last forever. Your 7-year-old brought to the doctor's office just as it opens, having been up all night gasping for breath. The 2am trip to the emergency room with your child who is having severe breathing troubles and will need to be admitted to the hospital...AGAIN!
Childhood asthma, always a common problem, seems to be the disease of the new millennium. More and more children are diagnosed and they seem to be getting sicker, despite a whole new arsenal of treatments and an improved understanding of the disease. No one really knows why this is happening. Speculation ranges from exposure to environmental toxins such as cigarette smoke to allergies related to insects to an increasing genetic predisposition to the disease.
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Whatever the cause, the results are clear. Asthma is a major problem for our children that must be aggressively treated. Treatment of childhood asthma cannot be successful unless parents become involved and educated about the causes, classification and treatment options for this chronic disease.
What's in a Name?
Before we can talk about this illness, we must decide just what to call it. This is not as easy as it may sound. The word "asthma" means different things to different people. It can be a frightening label to place on a child.
As a result, doctors are now trying to avoid using the word "asthma" in favor of another name: reactive airway disease. Doctors like this name since it more accurately describes what is happening in our young patients. The problem, in my experience, is that when I tell parents that their child has reactive airway disease, they have no idea what I'm talking about. The word asthma, however, seems to be clear to everyone.
No matter what words are used, it is of the utmost importance that the child and his/her parents understand the disease and its ramifications. Patient education is the key to the successful treatment of asthma. Unfortunately, this education can be complicated and it takes time, a commodity often in short supply in many pediatric offices.
Does My Child Have Asthma Or Not?
This is a simple question with a not-so-simple answer. Making the diagnosis of asthma can be very easy in a child with repeated classic episodes of wheezing that respond to standard treatment and a strong family history of asthma. But what about children without a family history who only have occasional, mild and/or less obvious symptoms? Unfortunately, in these cases the diagnosis of asthma is not always easy and can be missed.
Pulmonary function tests
In adults and older children, pulmonary function tests can be used to help make the diagnosis. These tests, which are painless and involve various breathing maneuvers, measure various aspects of lung function that become abnormal in people with asthma. Because patient cooperation and understanding are required to obtain good results, pulmonary function tests are less useful in younger children. They are often more useful in monitoring your child's progress than they are in making the diagnosis.
A clinical decision
Even in the modern era, the diagnosis of asthma in the majority of children requires a clinical decision by the pediatrician. Your child's doctor will require your help in making this decision. You will need to give a good history of your child's illness. When did the symptoms begin? What exactly are the symptoms: wheezing, cough, breathing distress, or blueness of the lips? Does anything seem to bring the symptoms on, such as exercise, illness, or exposure to smoke or animals? Do symptoms occur in one season of the year or all year round? Do other family members have similar illnesses, particularly asthma, eczema, or seasonal allergies? These are just some of the questions you may be asked.
In its classic form, asthma will be suspected when your child has repeated episodes of wheezing that are reversible with treatment. I always ask what parents mean when they say their child is wheezing. Parents often mean that their child has noisy breathing or has croup or is congested. It is important to understand that "wheezing" has very particular characteristics. Wheezing is a high-pitched, whistling kind of noise that comes from the lower airways in the chest, not from the nose or neck. It is usually worse when your child breathes out (expiration) rather than when he/she breathes in (inspiration), although in severe cases it can occur at both times. Parents may confuse noisy breathing or congestion with wheezing, though these are separate entities. Another important thing to understand is that not all people with asthma have wheezing. In its mildest form, there is only a lengthening of the breathing out phase that requires a stethoscope to hear.
Other signs and symptoms
Some patients do nothing but cough. Their cold symptoms, particularly their coughing, last for weeks without responding to cough medicine or antibiotics. This is especially true of younger children in whom mild asthma symptoms are commonly misdiagnosed as "bronchitis" and treated with repeated courses of antibiotics. In my opinion, a child with multiple episodes of "bronchitis" and "pneumonia" is often an undiagnosed asthmatic who is not being treated for his underlying problem. Some people only have asthma symptoms in very specific settings, such as after exercise or when exposed to irritants such as cigarette smoke, chemical fumes or animals.
What Is Asthma, Anyhow?
Here's where we get back to 'reactive airway disease'. Asthma is one of a family of diseases known as atopic diseases. These include the skin disease eczema and hay fever, or seasonal allergies.
In these diseases, the body's immune system tends to overreact to irritants. When an irritant is encountered, instead of a measured reaction to "fight off" the threat, the immune system goes into overdrive, causing inflammation. The inflammation causes many of the symptoms of these diseases. For example, in hay fever the "twitchy" lining of the nose and eyes overreacts to pollen, causing sneezing, runny nose and watery eyes. In eczema, the "twitchy" skin becomes red, itchy and may develop a rash in response to irritation. In asthma, the excess inflammation of the airways results in wheezing, coughing, and difficulty breathing.
Anatomy Of The Small Airways
In order to fully understand asthma, you have to know how the small airways inside your lungs are put together. These small airways are tubes that carry the air in and out of our lungs. They are composed of a supportive layer of fibrous tissue, a layer of muscle and an inside lining. The lining is like the lining in your nose and is called a mucus membrane. Mast cells, special immune cells present in the lining, are the body's early warning system for invaders. They are covered with little triggers (receptors) that, when stimulated, cause the mast cell to release its contents.
Mast cells on the move
The mast cells' contents include chemicals that signal the "troops" of the immune system to fight invaders and prepare the body for battle. Some of the released chemicals are well known, such as histamine (the rationale for using anti-histamine medication for allergies), while others are less well understood. These chemicals are responsible for most asthma symptoms. For example, they make the muscle layer of the small airways contract, causing narrowing of the airways (known as bronchospasm) and wheezing or difficulty breathing. They also make the mucus membrane "leaky" which causes congestion inside the airway.
The body's inflammatory reaction was designed to protect the airways. Unfortunately, due to some sort of genetic predisposition, children with asthma have overly reactive airways. The inflammatory process is triggered by minor irritants that would not cause a response in a child without asthma. In addition, the response is often excessive and the resulting inflammation and bronchospasm cause the symptoms of an asthma attack.
Anatomy Of An Asthma Attack
Your child is going about her business, when suddenly she is challenged with an asthma trigger. The mast cells release their chemicals and all sorts of things transpire. These reactions are generally divided in two categories: the early phase and the late phase.
The early phase
The early phase of an asthma attack is caused mostly by bronchospasm. It occurs within minutes, and lasts up to several hours. When the layer of muscle around the airways contracts, the airways narrow and bronchospasm occurs. Due to the physics of airflow, as the airways narrow, it is harder for the air that you breathe to get out of your lungs. This results in coughing, with or without the expiratory wheezing, that often occurs with an asthma attack.
The late phase
The late phase of an asthma attack is caused by inflammation of the airways and occurs over days, sometimes lasting for weeks if left untreated. It occurs because immune cells continue to release inflammatory chemicals. These chemicals cause the mucus membranes to leak, allowing fluid and more immune cells to enter the airways, clogging them up. The end result is further worsening of airflow.
Asthma: a chronic inflammatory disease
This leads us to the main take-home message for treating asthma. Asthma is a chronic inflammatory disease. If you treat only the sudden episodes of bronchospasm and inadequately treat the chronic inflammatory response (or late phase), then all but the mildest forms of asthma will not respond well to treatment over time. Even more alarming is the increasing evidence that chronic inflammation, if not adequately treated, may cause an actual change in the physical structure of the airway (airway remodeling). This remodeling may be permanent, causing an increased susceptibility to asthma symptoms in the future.
What Causes Asthma?
Asthma is multi-factorial. This means that it has not one cause, but many causes.
It is clear that there is definitely an underlying genetic tendency to have an overly reactive immune system. There are over 30 genes that scientists currently suspect are involved in the process. While science may eventually find a gene-based therapy for asthma, a family history of atopic disease currently means that your children are more likely to suffer from asthma.
Triggers and viral infections,br> Different people have different trigger factors that precipitate an asthma attack. It is like walking up a flight of stairs. When you get to the top, you have asthma symptoms. The first step in the staircase is your family history and your genetic predisposition. The next step up is exposure to specific environmental triggers. These include many factors such as cigarette smoke, pets, dust, insects, pollen, mold and fumes. The most common final step for many is viral infections, which kids get all the time. The irritation caused by these common infections may trigger a much more dangerous asthma attack. If one could remove an environmental irritant step, particularly smoking, dust and pets, perhaps some of our children might not reach the level of a severe attack of asthma.
How About Treatment?
When people talk about treating asthma, the focus seems to always be on the use of medical therapies like medications or allergy shots. A discussion of medical therapy is an entirely separate and lengthy topic. What must be remembered is that while vigorous and often chronic use of medications may be necessary, neglecting other forms of treatment is a huge mistake. Control of the environment around your asthmatic child is as important as medication. If one eliminates as many triggers as possible, less aggressive medical therapy will be needed.
The treatment of any chronic disease, particularly one in children, is a complicated task. There are many different ways to approach it. It is my responsibility as a doctor to explain the disease and treatment options in a way that you understand. All of the treatment options require a partnership between your child's pediatrician and you. Only when you understand and cooperate in a treatment plan, agreed upon with your doctor, can your child with asthma receive the best of care.