Making the right asthma diagnosis

By Donya Betancourt

The signs and symptoms of asthma were discussed in last week's article. But making a conclusive diagnosis of asthma is not always easy, writes Dr. Donya Betancourt in the second of a three-part series on the respiratory condition.

SANUR, Bali (JP): Diagnosing asthma can be difficult because children with the condition can have very different patterns of symptoms. For example, some children cough constantly at night but seem fine during the day. Others seem to get frequent chest colds that don't go away. Asthma tends not to be an isolated event -- if your child coughs in spasms with each cold he or she catches, then it may possibly be asthma.

It is easiest to diagnose asthma if the child has symptoms of wheezing, repeated coughing that worsens at night, shortness of breath and tightness in the chest. Adult symptoms are often similar to other lung conditions such as emphysema, heart failure or laryngeal dysfunction (shortness of breath, wheezing, coughing and tightness of the chest).

When considering a diagnosis of asthma, a doctor rules out every other possible cause of the symptoms, such as emphysema, allergies and laryngeal dysfunction. Questions will mostly be asked about the family history of asthma and allergies, illnesses (how often the child gets a cold, how severe and how long they last) and triggers or other things that seem to lead to a flare- up. A physical exam and possible laboratory tests such as a chest X-ray, blood tests or skin tests to check for allergies will also help in the diagnosis.

If you see a pulmonologist (lung specialist) or allergy specialist, he or she can perform a breathing test. This definitive test uses a spirometer, a machine that performs a lung function test, an analysis of a child's airflow through both large and small airways. The test is usually done before and after taking a medication known as a bronchodilator, which opens the airways. If the airways open significantly after taking the medication, it is likely the child has asthma.

Children under the age of 5 are not given a breathing test. Instead, doctors look for the right constellation of symptoms -- cough and/or wheezing, and/or shortness of breath and the nature of the cough, like whether it occurs in a series or in spasms. If the symptoms have a history of recurrence, that suggests asthma.

One of the simplest lung function tests uses a peak-flow meter to measure the rate at which you expel air. The rate gives vital information about the current state of your asthma. If your asthma symptoms are under control, your airways are open and you can force more air into the peak-flow meter. But if your airways are inflamed and constricted, you will not be able to blow as hard into the meter, making your peak-flow rate lower. You can also use a peak-flow meter at home to help detect subtle airway obstructions before you notice any symptoms. This device is not meant for anyone below the age of 6.

Once asthma is diagnosed, the symptoms can be placed into four main categories, each of which requires different treatment approaches.

1. Mild intermittent asthma. Describes patients who have asthma symptoms two or fewer times a week and/or two or fewer times a month at night.

2. Mild persistent asthma. Refers to patients who have symptoms more than twice a week but not daily (three to six times/week) and/or three to four times/month at night, and the symptoms may affect normal physical activity.

3. Moderate persistent asthma. Daily symptoms and/or five times or more per month at night. The symptoms require daily medication and affect normal physical activity

4. Severe persistent asthma. Patients have symptoms continuously, the asthma is poorly controlled and limits physical activity.

Every patient needs to follow an asthma management plan to control their symptoms. The severity of symptoms can both worsen and improve over time, and placement in a new asthma category will require different treatment.

Once a child is diagnosed with asthma, the family can begin learning how to control asthma so it no longer controls the family.

The writer is a pediatrician based in Sanur, Bali. Next week -- what everyone should know about asthma control.