Asbestosis Diagnosis

Diagnosis

Asbestosis is an aggressive pulmonary disease that can be challenging to diagnose since symptoms resemble those of less serious conditions like asthma and pneumonia. The disease develops in the lung tissue of people who have experienced heavy asbestos exposure. Most cases are marked by scarring of the lungs and if asbestosis is diagnosed early, prognosis and treatment options can improve.

A complete medical evaluation is needed before a proper asbestosis diagnosis can be made. This includes reviewing potential asbestos exposure, work history, symptoms and undergoing various tests and imaging scans that can detect lung abnormalities. Most cases are diagnosed late because symptoms do not develop until the condition has reached a more developed stage. However, early detection is possible if those previously exposed to asbestos receive annual medical exams that check for asbestos-related disease.

Asbestosis is similar to other asbestos-related conditions in that it is a terminal illness. According to the most recent data available, more than 1,400 asbestosis-related deaths were recorded in the United States in 2005. If you have experienced exposure to asbestos and are feeling chest pain or any other respiratory symptoms, it's important to schedule an appointment with your doctor.

How to Recognize Symptoms

Symptoms

Symptoms of asbestosis generally consist of respiratory problems. The two most common symptoms are coughing and shortness of breath, followed by chest pain and clubbing of the fingers. In the early stages of the disease, people experience shortness of breath and fatigue during physical activity. As the condition progresses, being short of breath even while doing very little becomes an issue. This is usually enough to encourage someone with asbestosis to take the first step in the diagnostic process and schedule an appointment with their primary care physician.

Diagnostic Process

Diagnosing asbestosis is not simple, and it can mean a number of visits to the doctor and a variety of tests. It's possible or even likely that a primary care physician may not be able to diagnose or detect asbestosis because its early symptoms are like those of so many other conditions. For this reason, patients may be sent to an oncologist or pulmonologist for additional testing. An oncologist or pulmonologist can determine which tests or imaging scans are needed and how to evaluate each of them.

An oncologist or pulmonologist are also more familiar with the criteria for confirming a diagnosis of asbestosis and ruling out other asbestos-related diseases like mesothelioma or lung cancer. Before asbestosis can be considered as a probable cause of symptoms, several indicators must be present, including a history of asbestos exposure, a latency period between the exposure and the onset of symptoms, evidence of structural changes to the lungs and evidence of cause.

  • Asbestos Exposure History

    For someone to be at risk for developing asbestosis, there has to be a time during their life of consistent and extended exposure to asbestos, often for more than five years. All sources of asbestos exposure should be discussed during the evaluation and if possible, identify the duration, intensity and circumstance under which the exposure occurred.

    Any history of asbestos exposure should start with a work history. Most people diagnosed with asbestos-related diseases, including asbestosis, come into contact with the mineral while on the job, so a job history is an important factor. Previous occupations should be questioned.

    There is no such thing as an occupation that is most at risk, but several of them are: welders, shipyard workers, miners, insulators, roofers, floor installers, drywall installers and auto mechanics. In addition, those who served in the military are considered high-risk for developing an asbestos-related disease.

  • Latency Period

    Latency – the amount of time between excessive exposure to asbestos and the time someone is confirmed to have the disease – is an integral part of the diagnostic process. If fibrosis is detected within only a few years since exposure, doctors are likely to look at other lung diseases before confirming asbestosis. Depending on the level of exposure, asbestosis usually takes 20 years or more from the time of initial exposure to present symptoms. Although clinical signs of asbestosis development can be seen in imaging scans as early as five years after exposure, such early detection is rare.

  • Evidence of Structural Changes

    An asbestosis diagnosis cannot be confirmed until imaging scans demonstrate structural changes to the lungs. Signs of pleural thickening, pleural effusion and scarring are all indicators that asbestosis may be present.

  • Evidence of Causatin by Asbestos

    Even though asbestos exposure may have occurred, it does not mean someone will develop lung problems as a result. Having occupational or environmental history as a probable source for exposure is necessary before asbestosis is even considered. In addition, the presence of pleural plaques or asbestos fibers in the lung tissue is the kind of evidence that often leads to an absolute diagnosis.

    To accurately diagnose and confirm asbestosis, one or more tests may be required. Evaluating a series of imaging scans is the most common technique used to diagnose asbestosis.

  • Asbestosis Tests and Imaging Scans

    One of the first tools a doctor will use in the diagnostic process is a stethoscope, which allows them to listen to the lungs. If the lungs are affected, the doctor will likely hear a dry, crackling sound while the patient breathes. After the preliminary physical examination, doctors will perform a range of tests and imaging scans before an asbestosis diagnosis can be confirmed.

    Tests for asbestosis will analyze lung function or collect a lung sample for lab testing. A series of imaging scans are also required to detect locations where asbestos fibers have caused scarring of the lungs. While evaluating the results of these imaging scans, an oncologist will look for dark spots or pleural thickening as signs of asbestosis.

    Some of the most common tests and imaging scans used to diagnose asbestosis include:

    • Pulmonary Function Test: This test, which can be used for people suspected of having asbestosis, determines how well lungs are functioning. It is designed to test the air capacity of the lungs (how much air they can hold) and determine how well air flow is going in and out. The most common way of measuring these functions is by blowing into an instrument called a spirometer. Some reports have indicated the occurrence of abnormal pulmonary function tests in 50 to 60 percent of asbestosis patients. One of the key signs of the disease is a reduction in forced vital capacity, or the most air a patient can force from their lungs after a full inhalation.

    • Bronchoscopy: Your doctor may recommend a bronchoscopy, where a thin fiber-optic scope is inserted into the lungs. This procedure is performed to obtain fluid or tissue samples from the lung area. A patient whose diagnosis is difficult to confirm may undergo this procedure so that fluid and tissue samples can be tested to ensure a correct diagnosis.

    • Chest X-Ray: Diagnosing asbestosis may also involve undergoing a chest X-ray, which is used to detect any abnormalities present in lung tissue. On an X-ray, scarred lung tissue developing from asbestos exposure appears as dark, opaque areas, meaning light has a difficult time passing through it. In advanced cases of asbestosis in which an entire lung is affected, the area may have a honeycomb-like appearance in the upper lobe. Bilateral interstitial fibrosis, meaning both lungs exhibit fibrosis, may also be present.

    • CT Scan: A computerized tomography (CT) scan may be recommended by the doctor to confirm a diagnosis of asbestosis. A CT scan can also be used for screening purposes, as these scans can sometimes detect asbestosis sooner than chest X-rays. In most cases though, a CT scan is used when doctors cannot get a confirmation from a chest radiograph.

Grades for Diagnosing Asbestosis

Doctor with Patient

Determining the extent of asbestosis is not an easy task for doctors. Few tests can recognize the early lung changes associated with the disease and imaging scan results often resemble signs of other asbestos-related conditions. When diagnosing asbestosis, the three grades often used include A, B and C. At Grade A, an occasional bronchiole is affected. For a Grade B diagnosis, patients must show signs of having more than the occasional bronchiole affected. A Grade C diagnosis occurs when more than half of the bronchioles are affected.

Histologic Grades of Asbestosis

Grade of Severity

  • Grade 0

    Early fibrosis involving walls of at least one respiratory bronchiole, with or without extension into nearby tissue. Fibrosis is confined to alveolated walls of respiratory bronchioles and ducts and not present in more distant alveoli. Inflammation similar to that caused by cigarette smoking may be observed.

  • Grade 1

    Early fibrosis involving walls of at least one respiratory bronchiole, with or without extension into nearby tissue. Fibrosis is confined to alveolated walls of respiratory bronchioles and ducts and not present in more distant alveoli. Inflammation similar to that caused by cigarette smoking may be observed.

  • Grade 2

    More severe fibrosis involving alveolar ducts and/or two or more layers of adjacent alveoli. Normal lung tissue remains in an area between adjacent bronchioles.

  • Grade 3

    Fibrosis is advanced and involves alveolar ducts and all layers of adjacent alveoli. All lung tissue between at least two adjacent bronchioles is affected. Some alveoli are completely damaged.

  • Grade 4

    Honeycomb-like appearance and large (up to 1 cm) dilated spaces largely visible in lung parenchyma, or the alveolar tissue.

Grade of Extent

  • Grade A

    Only occasional bronchioles are involved. Most appear normal.

  • Grade B

    More than occasional but less than half of bronchioles are involved.

  • Grade C

    More than half of bronchioles are involved.

Developed in 1980 by a committee of the College of American Pathologists.

Steps After an Asbestosis Diagnosis

Once asbestosis is confirmed, the next step is learning about treatment options. Available treatments will largely depend on how far the disease has progressed. If the condition is caught early enough, treatments like surgery and lung medications can be effective. When diagnosed in later stages of development, medications and oxygen can provide symptom relief.

Additional Resources

  1. Dodson, R. and Hammar, S. (2011). Asbestos: Risk Assessment, Epidemiology, and Health Effects. Boca Raton: Taylor & Francis.
  2. Dugdale, D., Hadjiliadis, D., & Zieve, D. (2011, June 10). Asbestosis. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/000118.htm
  3. UCSF Medical Center. (2011, Aug. 17). Asbestosis Diagnosis. Retrieved from http://www.ucsfhealth.org/adult/medical_services/pulmonary/old/conditions/asbestosis/diagnosis.html
  4. National Institute for Occupational Safety and Health. (2008, Jun. 23). Asbestosis: Number of Deaths, Crude and Age-Adjusted Death Rates, U.S. Residents Age 15 and Over, 1968-2005. Retrieved from http://www2a.cdc.gov/drds/WorldReportData/FigureTableDetails.asp?FigureTableID=488&GroupRefNumber=F01-01
  5. Agency for Toxic Substances and Disease Registry. Transcript for ATSDR’s Environmental Medicine Grand Rounds: Asbestos Toxicity. Retrieved from http://www.atsdr.cdc.gov/csem/asbestos/grand_rounds/asbestos_grand_rounds_transcript.pdf
  6. Agency for Toxic Substances and Disease Registry. Asbestos Toxicity: What Tests Can Assist with Diagnosis of Asbestos Toxicity? Retrieved from http://www.atsdr.cdc.gov/csem/csem.html
  7. Interstitial Lung Disease – Mayo Clinic. (July 2011) Retrieved from http://www.mayoclinic.org/diseases-conditions/interstitial-lung-disease/basics/definition/CON-20024481

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