Asbestosis

From Wikipedia, the free encyclopedia

**Asbestosis**
*Classifications and external resources*
Image:Early Asbestosis in a Retired Pipe Fitter.jpg
Chest X-ray in asbestosis shows plaques above diaphragm
ICD-10	J61
ICD-9	501
DiseasesDB	928
MedlinePlus	000118
eMedicine	med/171 radio/52

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).

1 Signs and symptoms
2 Pathogenesis
3 Treatment
4 Legal issues
5 References
6 External links

[edit] Signs and symptoms

The primary symptom <ref name="Roggli1">Pathology of Asbestos-Associated Diseases, Victor L. Roggli, Tim D. Oury and Thomas A. Sporn, Springer, ISBN 0-387-20090-8</ref> 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 <ref name="Becklake">Becklake MR. Asbestos-related diseases of the lung and other organs: Their epidemiology and implications for clinical practice. Am Rev Respir Dis 1976;114:187-227</ref> . 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 <ref name="Burdorf">Occupational Characteristics of Cases with Asbestos-related Diseases in The Netherlands, ALEX BURDORF, MOHSSINE DAHHAN, and PAUL SWUSTE, Ann. Hyg., Aug 2003; 47: 485 - 492.</ref><ref name="Gilson">HYGIENE STANDARDS FOR AIRBORNE AMOSITE ASBESTOS DUST: BRITISH OCCUPATIONAL HYGIENE SOCIETY COMMITTEE ON HYGIENE STANDARDS, Committee on hygiene standards:, J. Glover, J. M. Barnes, D. Turner, S. A. Roach, D. E. Hickish, Sub-committee on asbestos:, J. C. Gilson, C. G. Addingley, G. Berry, S. Holmes, R. Hunt, H. C. Lewinsohn, S. G. Luxon, W. J. Smither, and S. A. Roach, Ann. Hyg., April 1973; 16: 1 - 5.</ref> , and only indirect exposure (through air ventilation system.)

[edit] Pathogenesis

Asbestosis is the scarring of lung tissue (around terminal bronchioles and alveolar ducts) resulting from the inhalation of asbestos fibers <ref name="Icon Guide">Asbestosis: A Medical Dictionary, Bibliography, And Annotated Research Guide, Icon Health Publications, ISBN 0-597-84339-2</ref> . 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. This inflammatory reaction can be described as a chronic form rather than acute, with a slow yet ongoing progression of the bodies immune system in an attempt to eliminate the foreign fibres. Macrophages phagocytose (ingest) the fibers and stimulate fibroblasts to deposit connective tissue. Due to the Asbestos fibres natural resistance to digestion, the macrophage will die off, releasing certain cytokines and attracting further lung macrophages and fibrolastic cells to localise and lay down firbous tissue, which eventually forms a fibrous mass. 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 <ref name="Roggli2">Asbestos content of lung tissue and carcinoma of the lung: a clinicopathologic correlation and mineral fiber analysis of 234 cases, Victor L. Roggli and Linda L. Sanders, Ann. Hyg., Apr 2000; 44: 109 - 117.</ref><ref name="Burdorf2">An Expert System for the Evaluation of Historical Asbestos Exposure as Diagnostic Criterion in Asbestos-related Diseases, Alex Burdorf and Paul Swuste, Ann. Hyg., Jan 1999; 43: 57 - 66.</ref> , the drastic reduction in lung function due to the stiffening of the lungs and reduced TLC may induce heart failure (cor pulmonale).

[edit] Treatment

There is no curative treatment <ref name="Castleman">Asbestos: Medical and Legal Aspects, Fifth Edition, Barry I. Castleman, Aspen Publishers, ISBN 0-7355-5260-6</ref> . 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.

[edit] 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 <ref name="Castleman"/> , 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.