How Bronchitis is Diagnosed: Bronchitis Tests

While a husky cough may be symptomatic of the common cold, it can also indicate that you may suffer from bronchitis. If you suspect that you have bronchitis, your doctor will perform a series of tests to make the official diagnosis. In some cases, he may call for further testing to evaluate whether or not you suffer from any other underlying condition so he can determine the proper course of treatment.

Understanding Bronchitis

Bronchitis is a condition marked by the irritation of the bronchial tubes, the passageways that allow oxygen from the windpipe to enter the lungs. The interior of each bronchus contains a mucus lining and tiny hairs, known as cilia. Although the nasal entry traps most viruses and debris, when these molecules escape and travel toward the lungs, they can create negative health consequences.

Coughing is the body's natural reaction to this invasion. While the bronchitis virus generally lasts for only a few days, smokers (or those exposed to secondhand smoke or other irritants) are more likely to suffer from a long-term form of inflammation, known as chronic bronchitis.

Making a Bronchitis Diagnosis

When making a bronchitis diagnosis, your doctor will ask basic questions about whether or not you suffer from the following symptoms:

• a cough that worsens throughout the day
• breathing difficulties
• flu-like symptoms, including mild chills, headache and fever
• mucus when coughing, often thick with white or yellow-green coloration
• tight sensation in the chest area
• wheezing.

If your doctor suspects chronic bronchitis, he may ask the following questions about lifestyle to determine the reasons you suffer from this condition:

• Are you exposed to secondhand smoke?
• Do you have trouble breathing under exertion, such as when climbing stairs?
• Do you smoke?
• Do you suffer from asthma?
• Do you work around chemicals or other pollutants?
• Have you been diagnosed with a lung ailment, such as COPD (chronic obstructive pulmonary disease)?
• Have you recently been exposed to someone who suffers from a cold?

Tests for Bronchitis

After asking the above questions, a physician will place a stethoscope on your chest and listen for breathing abnormalities. The presence of rasping sounds could indicate blockage in your lungs. While doctors don't need to take your blood, they often need to perform the following (listed in order of frequency performed, from most often to least often) to diagnose bronchitis:

• By tapping on your chest with two fingers, known as percussion, your doctor can locate the areas that are blocked.
• You may be asked for a sputum sample, a test in which the phlegm is microscopically viewed to determine if it is affected by the bronchitis virus.
• A routine chest X-ray can give the doctor better imaging of the pulmonary area, including the lungs, bronchial tubes and blood vessels. During a chest X-ray, you'll wear a hospital gown after removing clothing from the waist up. Standing in front of a metal plate, you will first face the front of machine and then rotate 90° so the machine can take images from the side. A beam of radiation focuses briefly on the chest area to create film, similar to a negative. This painless procedure doesn't exposure patients to harmful levels of radiation. Once the test is completed, you'll be asked to wait before dressing. A radiation technologist will review the film to be sure the images are clear and readable.
• The peak flow meter test judges the extent of bronchial blockage by measuring the amount of air a patient exhales. During the test, you're required to breathe out as quickly and as hard as possible. A special device determines the flow rate in percentages referred to as PEFR (peak expiratory flow rate). An 80 percent or higher reading means lung function is generally manageable. Peak flow meter tests can be administered in a doctor's office or at home for those with chronic bronchitis who need to take regular readings. Standing or sitting, the test requires that you force-breathe three times in a row. The highest number is your final reading for that session.
• Spirometry is another breathing test that incorporates PEFR with inhaling to measure lung capacity. The additional measuring points are VC, or FEV6/FVC, in which VC refers to volume and FEV1 reflects the highest level or flow of air exhaled within a specified timeframe. During the test, patients are asked to inhale as much air as they can and then exhale as quickly and forcefully as possible for up to six seconds. The results will help determine the extent of pulmonary disease or irritation that is potentially blocking the lungs.
• If, at this point in the diagnostic bronchitis testing your doctor is still unsure of whether or not you have bronchitis, he will use the arterial blood gas (ABG) test. While the previous tests for bronchitis are non-invasive procedures, the ABG test is invasive. The ABG test pinpoints respiratory difficulties and also measures the effect of medications or treatments following a bronchitis diagnosis. During this test, a nurse inserts a needle into an artery, rather than a vein, at the wrist to collect blood gases. The results will show the level of carbon dioxide and oxygen present in the blood. Because arteries lie deeper than surface veins, this procedure generally causes some pain. The nurse may anesthetize the area before performing an ABG test.

Once your physician makes a proper bronchitis diagnosis, treatment may proceed in a variety of ways depending on the precise causes of the condition and your medical history.

Resources

Chidekel, Aaron, S., M.D. (2004). What is Bronchitis? Retrieved July 26, 2007, from the KidsHealth Web site: http://www.kidshealth.org/teen/infections/common/bronchitis.html.

Ehealthmd.com (2002-2005). What are the Symptoms of Bronchitis? Retrieved July 26, 2007, from the EhealthMD web site: http://www.ehealthmd.com/library/bronchitis/BCH_symptoms.html.

Lungusa.org (2007). Spirometry and Other Lung Function Tests Fact Sheet. Retrieved July 26, 2007, from the American Lung Association Web site: http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E