by Y Tian

Created on: March 05, 2011

Asbestos is a generic term used to group six different mineral silicates such as chrysolite, amosite and anthophyllite. These mineral silicates have been used by humans for as long as 4,500 years to strengthen earthenware pots and cooking utensils. But the use of asbestos really became widespread during the industrial revolution of the 18th century. Since then, asbestos has been used for a variety of uses including building insulation, fire retardant coatings, pipe insulation and ceiling insulation. In 1906, the first documented death related to asbestos occurred. But it was only in the 1970s that the public became aware of the dangers of asbestos exposure. Gradually, the substance became banned in many first world countries. However, even now, people are still suffering from the health problems associated with asbestos exposure.

Asbestos becomes a health hazard when it is disturbed and fibers are dislodged. These asbestos fibers are invisible to the naked eye and once airborne, can be easily inhaled. Once these fibers enter the lung, they become trapped there. High concentrations of asbestos fibers inhaled over a long time period can cause serious health problems. The two most common diseases associated with asbestos exposure are asbestosis and mesothelioma.

Asbestosis is a serious respiratory disease caused by the body’s reaction to the inhaled asbestos fibers. When the asbestos fibers become trapped in the alveoli of the human lungs, the body’s immune system is triggered and an inflammatory reaction to the fibers occurs. Macrophages attempt to ingest the fibers but because of their natural resistance, the macrophages eventually die off. The cytokines released from the dying macrophages in turn attract more macrophages to the area. Meanwhile, fibroblasts are also stimulated to come into the area and deposit connective tissues. The actions of these two types of cells eventually cause fibrosis to the lung and reduce the lungs’ capacity for oxygen transfer.

Clinically, asbestosis causes shortness of breath, especially on exertion. The severity of the disease depends on the amount of asbestos inhaled by the patient. Advanced cases of the disease may even lead to respiratory failure. As asbestos fibers are trapped inside the lung, there is no curative treatment for asbestosis. Treatments such as oxygen therapy can only relieve the breathing difficulties. In addition, patients with asbestosis are more likely to develop certain malignancies such as mesothelioma.

Mesothelioma is a certain type of cancer that most commonly originates from the pleura linings of the lung. In most cases of mesothelioma, a history of asbestos exposure exists. The trapped asbestos fibers may be carried to the pleural surface (the lining of the lung) and lead to the development of malignant mesothelial plaques. Signs and symptoms of mesothelioma include chest wall pain, shortness of breath, fatigue, wheezing and cough. Due to the fact that these symptoms are quite similar to those of many other conditions, diagnosis is quite difficult. Often, a biopsy is needed for confirmation. Prognosis for mesothelioma is low.

As noted above, the health dangers associated with asbestos exposure is extremely high. It is because of this that the use of asbestos has decline and in some countries banned. Asbestos is highly dangerous and should be treated seriously.

References:

Spetzer, F. (2005) Environmental Lung Diseases. Harrison's Principles of Internal Medicine 16th Edition. USA: McGraw-Hill Companies, Inc.

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