Bronchitis - Diagnosis

To diagnose bronchitis, the doctor first takes the patient's health history and observes his or her symptoms. The doctor then listens to the patient's chest with a stethoscope. Certain sounds indicate narrowing of the airways. These sounds include moist rales, crackling, and wheezing. Moist rales is a bubbling sound caused when fluids are present in the bronchial tubes.

A sputum culture may be performed, especially if the sputum is green or has blood in it. The culture allows the doctor to determine what kinds of bacteria are present in the sputum. He or she can then decide what kind of drugs to use in killing the bacteria.

The first step in taking a sputum culture is to have the patient cough up a small amount of sputum (material from the lungs). The sample is then placed in a warm environment for two to three days. Under these conditions, bacteria grow rapidly and are easy to identify. Sputum can also be collected by means of a bronchoscopy. In this procedure, the patient is first given a local anesthetic. A tube is then passed down the airway to collect a sputum sample.

Another step in diagnosing bronchitis is a lung function test. This step requires the use of a spirometer, which is a device that measures the amount of air entering and leaving the lungs. The test is performed by having the patient breathe into the spirometer, first normally and then with force. The test is quick, easy, and painless. It is usually done in the doctor's office. A lung

The American Lung Association estimates that 80 to 90 percent of all cases of chronic bronchitis are caused by smoking. (Reproduced by permission of

AP/Wide World Photos

)

function of less than 80 percent can be the sign of bronchitis or a related lung disease.

Many lung diseases have similar symptoms. To tell them apart, a doctor may order other tests, such as a chest X ray, electrocardiogram (ECG; pronounced ih-LEK-tro-KAR-dee-o-gram), or blood tests. An ECG measures electrical activity in the heart. Other tests may be used to measure how effectively oxygen and carbon dioxide are being exchanged in the lungs.