Lt Col Reynolds
Diagnosing asthma can be difficult because signs and symptoms can range from mild to very severe and are often similar to those of other conditions, including emphysema, early heart failure, or a type of vocal cord dysfunction. Dr. Green, can you tell us how asthma is diagnosed?
Definitely, Dr. Reynolds. A complete physical exam is usually required in order to rule out other conditions. The provider will probably ask about periods of coughing, wheezing, shortness of breath, or chest tightness that come on suddenly, occur often, or seem to happen during certain times of the year or season. Patients may also be asked about colds that seem to "go to the chest" or take more than 10 days to get over, medicines they’ve used to help their breathing, family history of asthma and allergies, and things that seem to cause or increase symptoms.
The provider will then listen to the patient’s breathing and look for signs of asthma or allergies. Often a device called a spirometer will be used to check how the lungs are working. The test is called spirometry, and it measures how much air a person can blow out of their lungs after taking a deep breath, and how fast they can do it. The results will be lower than normal if the airways are inflamed and narrowed, or if the muscles around the airways have tightened up.
As part of the spirometry test, the provider may give the patient a medicine that helps open narrowed airways to see if the medication changes or improves test results.
If spirometry results are normal but a patient has asthma symptoms, the provider may suggest additional tests to determine the cause of the symptoms. These other tests may include:
- Allergy testing to determine the existence of any allergens
- A peak airflow test, in which the patient uses a peak flow meter every day for one to two weeks to check their breathing
- A methacholine challenge or bronchial challenge test, more commonly used in adult patients, to measure how much the lungs narrow in response to inhaled methacholine
- A test to see how the patient’s airways react to exercise
- Tests to check for gastroesophageal reflux disease, or GERD
- A test for sinus disease, or
- Other tests, such as a chest x-ray or an electrocardiogram, to rule out other lung or heart diseases that could be causing the symptoms