The first step in making a diagnosis of asbestosis, a disease caused by scar tissue in the lungs, is the medical and occupational history a doctor takes when first consulting with a patient. Since asbestosis is caused exclusively by inhalation of asbestos fibers, the doctor will want to know whether there is a chance that the patient’s current symptoms may be related to past asbestos exposure. Asbestosis can have a latency period of between 10 and 20 years, so the patient will likely need to give an occupational history that covers several decades.
Pulmonary Function Tests
If the doctor suspects asbestosis, there are several tests that can determine the nature of the lung problem. Pulmonary function testing measures airflow and volume of air in the lungs, and requires the patient to perform various activities that may include forced or rapid breathing or breathing in a gas such as nitrogen or helium. Measurements of amount and rate of breath are made using an instrument called a spirometer, so this process is also called spirometry.
Spirometry can alert the doctor if lung function is compromised, but it cannot always pinpoint the specific problem. Noninvasive imaging tests are often used to give the doctor a better look at the patient’s lungs. Simple chest X-rays are useful for this purpose, as lung scarring will appear as patches of excessive whiteness. Computed tomography (CT) scans also make use of X-rays to create an image of the inside of the body, but provide a more detailed image than a standard X-ray machine and are especially useful in diagnosing asbestosis in its earlier stages. Depending on the available equipment, the doctor may order a high resolution CT (HRCT) scan.
Finally, a bronchoscopy may be necessary to get a better picture of the patient’s airways and collect samples of lung or other tissue for analysis. A bronchoscope is a long, thin tube that is inserted into the patient’s nose or mouth and down the windpipe. Flexible bronchoscopes may be used with patients who are awake, but larger, rigid bronchoscopes require the patient to be under general anesthesia. The doctor may take a tissue sample either by injecting saline through the tube and collecting it again or by passing special brushes or needles through the tube to biopsy small pieces of the lung tissue.