Asbestosis

– A diffuse, interstitial pulmonary fibrosis resulting from inhalation of asbestos.

Causes and Incidence

The cause is prolonged exposure to airborne asbestos particles. Susceptibility increases with increasing length and intensity of exposure. The incidence is greatly increased by chronic occupational exposure. Families of workers are also at risk from fibers carried home on clothing. The general public is at risk from long-term exposure to asbestos dust in old buildings in which asbestos was used as insulation, or from asbestos in shingling or building material.

Disease Process

Asbestos particles are deposited on bronchiole or alveolar walls and are ingested by cells, leading to an edematous process in the wall that results in nonnodular alveolar and interstitial fibrosis, reduced lung volume and compliance, and impaired gas transfer.

Symptoms

Symptoms begin with exertional dyspnea and decreased exercise tolerance. As the disease progresses, dyspnea is chronic even at rest and a dry cough may develop.

Potential Complications

Asbestos is a cocarcinogen with tobacco, and asbestos workers who smoke are 90 times more likely to develop lung cancer than smokers who are not exposed to asbestos.

Diagnostic Tests

Clinical examination
History of long-term exposure to asbestos.

Radiology
Interstitial markings in lower lung, thickening, plaques, calcification.

Pulmonary function
Early: normal; later: reduced lung capacity and compliance.

Arterial blood gases
Early: normal; later: decreased PO2, increased PCO2.

Treatments

Surgery – None.

Drugs – None.

General – Eliminate exposure; chest physiotherapy, increased fluids, and steam inhalation to loosen secretions; oxygen therapy.

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