Definition of asbestosis

1) Asbestosis is a chronic inflammatory medical condition affecting the parenchymal tissue of the lungs. It is caused by the chronic inhalation of asbestos fibers. People with occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. There is an increased risk of lung cancer and mesothelioma associated with asbestosis. The risk is related to the total dose of asbestos received and the duration of asbestos exposure. Exposure to the crocidolite form of asbestos is the form most associated with mesothelioma among the four forms of asbestos. Mesothelioma usually occurs between 20-40 years after exposure to asbestos and has a very poor prognosis, with most patients dying within 2-4 years of diagnosis.
Inhalation of fibers of asbestos lead to development of alveolar and interstitial fibrosis of lung tissue. This leads to reduced lung capacity and compliance, leading to reduced gas transfer.
The primary symptom of asbestosis would be a slow, insidious onset of shortness of breath on exertion. In severe, advanced cases, this may lead to respiratory failure. Cough is not usually a typical symptom unless the patient has concomitant other respiratory tract diseases.
Diagnosis of asbestosis is largely dependent on a good and accurate clinical history taking. Occupational exposure to asbestosis is critical to the diagnosis. Histopathological diagnosis is usually not necessary for patient management but can be used to confirm the diagnosis in post-mortem.
Prevention of asbestosis involves identifying risk of exposure to asbestos and protection from dusts and inhaled substances at work.

Types of Asbestos:

Chrysotile, or white asbestos, is obtained from Canadian serpentine rocks. It is less friable (and therefore less likely to be inhaled) than the other types and is the type most often used industrially. Chrysotile should not be confused with chrysolite, a synonym of olivine.
Amosite, or brown asbestos, is an amphibole from Africa.Crocidolite, or blue asbestos, is an amphibole from Africa and Australia. It is the fibrous form of riebeckite.

Notes: Serpentine rocks are those with curled fibres. Amphiboles have straight, needle-like fibres.
The amphiboles, in their fibrous form, are friable and therefore the most carcinogenic, although they also exist in safer non-fibrous forms.
Other asbestos minerals, such as tremolite, actinolite and anthophyllite are not used industrially but occur in traces.

2) A lung disease (pneumoconiosis) resulting from inhaling fibers of asbestos and marked by interstitial fibrosis of the lung. (More information)