Article: Asbestosis

Chest X-ray in asbestosis shows plaques above diaphragm

Asbestosis is a chronic inflammatory medical condition affecting the parenchymal tissue of the lungs. It occurs after long-term, heavy exposure to asbestos, e.g. in mining. Sufferers have severe dyspnea (shortness of breath) and are at an increased risk regarding several different types of lung cancer.

As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to the World Health Organisation (WHO), these may defined as; asbestosis (the subject of this article), lung cancer, and mesothelioma (generally a very rare form of cancer, but increasing in frequency as people exposed to asbestos age).

Signs and symptoms

The primary symptom of asbestosis is generally the slow, insidious onset of shortness of breath on exertion. In severe, advanced cases, this may lead to respiratory failure. Coughing is not usually a typical symptom, unless the patient has other, concomitant respiratory tract diseases.

People with extensive occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. There is also an increased risk of lung cancer and mesothelioma. Asbestosis and lung cancer require prolonged exposure to asbestos. However, cases of mesothelioma have been documented with even 1-3 months of exposure, and only indirect exposure (through air ventilation system.)

Pathogenesis

Asbestosis is the scarring of lung tissue (around terminal bronchioles and alveolar ducts) resulting from the inhalation of asbestos fibers. When such fibers reach the alveoli (air sacs) in the lung, where oxygen is transferred into the blood, the foreign bodies (asbestos fibers) cause the activation of the lung's local immune system and provoke an inflammatory reaction. Macrophages phagocytose (ingest) the fibers and stimulate fibroblasts to deposit connective tissue. The result is interstitial fibrosis. The fibrotic scar tissue causes alveolar walls to thicken which reduces elasticity and gas diffusion, reducing oxygen transfer to the blood, as well as the removal of carbon dioxide. The total lung capacity (TLC) may be reduced through the alveolar walls thickening. In the more severe cases, the drastic reduction in lung function due to the stiffening of the lungs and reduced TLC may induce heart failure (cor pulmonale).

Treatment

There is no curative treatment. Close monitoring (routine X-rays or even pleural biopsy) for mesothelioma is mandated. Oxygen therapy at home is often necessary to relieve the shortness of breath. Supportive treatment of symptoms includes respiratory treatments to remove secretions from the lungs by postural drainage, chest percussion, and vibration. Aerosol medications to thin secretions may be prescribed.

Legal issues

Main article: Asbestos and the law

The first lawsuits against asbestos manufacturers were in 1929. Since then, many lawsuits have been filed against asbestos manufacturers and employers, for neglecting to implement safety measures after the link between asbestos, asbestosis and mesothelioma became known (some reports seem to place this as early as 1898). The liability resulting from the sheer number of lawsuits and people affected has reached billions of dollars. The amounts and method of allocating compensation have been the source of many court cases, and government attempts at resolution of existing and future cases.