Diagnosing asbestosis is complex, because it is a rare disease. When patients go to their primary care physician complaining of a persistent cough or shortness of breath, the doctor must first rule out more common illnesses such as asthma and pneumonia. Patients are then usually referred to a lung specialist or pulmonologist for additional testing.
However, even when a specialist sees the symptoms of asbestosis and signs of tissue scarring on imaging scans, this is only enough evidence to suggest some kind of lung scarring disease, referred to as pulmonary fibrosis or interstitial lung disease.
Many things can cause scarring in the lungs besides asbestos — radiation exposure, air pollutants and various autoimmune diseases — and in many cases, doctors never determine the exact cause.
Pinpointing asbestosis depends on the patient providing thorough medical and occupational histories that suggest high levels of asbestos exposure. A patient must report a history of asbestos exposure.
Testing for Asbestosis
One of the first tools a doctor will use in the diagnostic process is a stethoscope, which allows them to listen to the lungs. Scarring causes the lungs to make a dry, crackling sound when the patient breathes.
The doctor typically also has the patient perform a pulmonary function test to determine how the lungs are functioning. The patient blows into an instrument called a spirometer, which measures how much air the lungs can hold and how well air flows in and out.
Not all patients with asbestosis have abnormal pulmonary function test results, but one of the key signs of the disease is evidence of restrictive lung disease, which includes a reduction in forced vital capacity, or the most air a patient can force from their lungs after a full inhalation. Pulmonary function tests often reveal reduced lung function because of restriction caused by scarring.
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- Chest X-Ray
- Scarred lung tissue appears more opaque on an X-ray. In advanced cases of asbestosis, lung tissue may have a honeycomb-like appearance.
- CT Scan
- Doctors use computerized tomography (CT) scanning when X-ray results are unclear. CT scanning can also be used to regularly screen asbestos-exposed individuals, as these scans can sometimes detect asbestosis sooner than chest X-rays.
While evaluating imaging scans, the doctor can also check the pleural lining around the lungs for signs of asbestos exposure. Inhaling asbestos may lead to the formation of pleural plaques, which can support a diagnosis of asbestosis.
It is possible to examine a sample of lung tissue under a microscope to help confirm a diagnosis of asbestosis, but this is uncommon. Extracting a tissue sample requires an invasive bronchoscopy procedure, so doctors usually only recommend it as a last resort.
Establishing a History of Asbestos Exposure
Asbestosis is caused by inhaling asbestos. For a patient to be diagnosed with this disease, the patient’s history must reveal consistent exposure to asbestos for more than five years or a shorter period of extremely intense exposure. During their medical evaluation, the patient must discuss all sources of asbestos exposure with their doctor and identify the duration, intensity and circumstances under which the exposure occurred.
The long latency period of asbestosis is a key factor in diagnosing the disease. Depending on the level of exposure, asbestosis usually takes 20 years or more from the time of initial exposure to cause symptoms. If a patient develops symptoms within only a few years of being exposed to asbestos, doctors are likely to suspect other lung diseases.
Grades of Asbestosis Severity
- Grade 0
- Scarring affects the walls of some of the passageways (bronchioles) leading to the lungs’ air sacs (alveoli).
- Grade 1
- Scarring affects the walls of most bronchioles and some alveoli.
- Grade 2
- Scarring affects most bronchioles and alveoli.
- Grade 3
- Scarring is advanced and some alveoli are completely damaged.
- Grade 4
- Lung has a honeycomb-like appearance because of pervasive scarring.
6 Cited Article Sources
- Mayo Clinic Staff. (2017, August 12). Asbestosis Diagnosis and Treatment. Retrieved from: http://www.mayoclinic.org/diseases-conditions/asbestosis/diagnosis-treatment/drc-20354643
- U.S. National Library of Medicine. (2017, May 21). Asbestosis. Retrieved from: https://medlineplus.gov/ency/article/000118.htm
- Varkey, B., and Varkey, A. (2015, December 31). Asbestosis Workup. Retrieved from: https://emedicine.medscape.com/article/295966-workup
- Dodson, R., and Hammar, S. (2011). Asbestos: Risk Assessment, Epidemiology, and Health Effects. Boca Raton: Taylor & Francis.
- Roggli, V. et al. (2010, March). Pathology of Asbestosis—An Update of the Diagnostic Criteria: Report of the Asbestosis Committee of the College of American Pathologists and Pulmonary Pathology Society. Retrieved from: http://www.archivesofpathology.org/doi/full/10.1043/1543-2165-134.3.462
- American Lung Association. (n.d.). Diagnosing and Treating Asbestosis. Retrieved from: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/asbestosis/diagnosing-treating-asbestosis.html
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Last Modified December 18, 2018