U.S. studies have shown that deaths from asbestosis have been on the rise. This is in stark contrast from the mortality trends pegged by the other forms of pneumoconioses, which have been on a steady decline. Worse, these mortality numbers are expected to further increase in the coming years. In the four – year period (from 2001 to 2005), U.S. studies have pegged the estimated life years lost before the age of 65 that is attributable to asbestosis to be 7,267. With the aforementioned dismal figures, the prompt recognition of asbestosis symptoms and subsequent institution of treatment is highly desirable.

Investigation into a possible exposure to asbestos in the patient’s past is pertinent. Symptoms of asbestosis usually appear after a latency period of 20 or so years. Dyspnea upon exertion is the most common and prominent symptom exhibited by patients. Patients may also report a non-productive cough, wheezing, and nonspecific chest pain. Fatigue and weight loss are also common complaints. As the disease progresses, the dyspnea worsens as well.

Rales or crackles heard during the end-inspiratory phase on physical examination are telltale signs of asbestosis. Rales may sound as fine as hair rubbing against each other, or coarse like snapping a Velcro open. Using a stethoscope, these rales are best heard over the bases of the lungs, in the postero-lateral chest wall. Physicians should maintain a high level of suspicion once rales are documented on physical examination, as these usually precede the characteristic pleural plaques seen on chest radiographs and abnormalities in pulmonary function tests. About a third of patients with asbestosis however do not manifest with rales. As the disease progresses, finger clubbing as well as restricted chest expansion are also evident. As asbestosis worsens, rales can now be heard all throughout the entire inspiratory phase.

Typical findings of asbestosis seen on chest radiographs include diffuse reticulonodular infiltrates seen in the bases of the lungs that obscure the heart border. Pleural thickening can also be seen, usually along the middle lung fields. Calcified pleural plaques are also found and are commonly located at the bases of the lungs, including the diaphragmatic pleura. Linear interstitial markings are commonly seen in the early stages of asbestosis. During its more advanced stages, honeycombing, which consists of cystic spaces surrounded by lung fields and interstitial infiltrates, is the more characteristic finding. In cases where in chest radiographic findings are not diagnostic, a high resolution computed tomography scan maybe used to help detect structural abnormalities consistent with asbestosis. Typical CT scan findings include subpleural linear opacities that are parallel to the pleura and fibrosis.

The patient's pulmonary function tests should also be investigated. The earliest abnormality seen with asbestosis is exertional hypoxemia. The lung’s diffusing capacity reduces. A reduction of the lung’s total capacity and vital capacity are also seen, which are consistent with other restrictive lung disease patterns. The FEV1/FVC ratio however remains unchanged. Monitoring of the patient’s oxygenation status should also be done employing pulse oximetry readings during cardiopulmonary stress tests and arterial blood gas analysis from timely arterial blood punctures. Invasive procedures such as broncheoalveolar lavage and biopsy are not necessary for diagnosing asbestosis.

The diagnosis of asbestosis is mainly clinical. A heightened index of suspicion armed with the knowledge of characteristic findings from physical, laboratory examinations and imaging studies on the part of physicians go a long way in helping to save people’s lives.