Lung Diseases - Immunology Of Occupational Lung Diseases Caused By Dust

Repeated and long-term contact to certain irritants on the job can actually lead to an array of lung diseases that may have lasting effects or even after exposure ceases. Certain occupations, because of their nature of the location, work and also environment, are more at risk for occupational lung diseases rather than others. Contrary to a popular misconception, the coal miners are not the only ones at risk for an occupational lung disease.

For instance, working in a car garage or textile factory can expose a person to various hazardous chemicals, dusts, and even fibers which may lead to a lifetime of lung problems if they are not properly diagnosed and treated. Occupational lung diseases are actually the number one cause of the work-related illness. Most occupational lung diseases are mainly caused by repeated, long-term exposure, but even a severe, single exposure to a hazardous agent can be dangerous and damageable for the lungs. Occupational lung diseases are quite preventable. Smoking can increase both the severity of an occupational lung disease and also the risk of getting lung cancer.

The lungs are exposed to a number of injurious substances. Such injury might be the result of immunological or even non-immunological mechanisms. The lung clears itself of inhaled particles by different means of ciliated cells lining the airways and the macrophages. The latter would play an important role in the immune process as well. Inorganic particles are ingested by macrophages and if they are found inert then they are transported for eventual expulsion.

Particles such as silica are poorly handled by the macrophages as they not only damage the macrophages but also impair their function as a result. Others, such as asbestos, may stimulate the fibrosis. Endogenous factors such as the presence of certain auto-antibodies (rheumatoid factor or anti-nuclear factor) may alter the response of the host to inhale the particles. The pathological changes caused by the handling of inorganic dusts would include intestitial fibrosis, nodular fibrosis or macule formation which would lead to emphysema.

Occupational asthma actually occurs when the individuals are exposed to dusts during their course of work. The lung would respond differently to the organic dust. T cells and complement are important elements in handling the organic dust. The role of inhaled steroids which have no such significant systemic effects in the prevention of certain occupational asthmas is actually worth evaluating, apart from control measures which may minimise the exposure.

Byssinosis is caused by the dust from hemp, flax, and also cotton processing. Also known as brown lung disease, the condition is very chronic and also characterized by the chest tightness and shortness of breath. Byssinosis also affects an estimated 35,000 textile workers, to date, both former as well as current.

Hypersensitivity pneumonitis is a lung disease which is caused by the inhalation of the fungus spores from the moldy hay, the bird droppings, and various other different organic dusts. The disease is characterized by inflamed air sacs in between the lungswhich would lead to fibrous scar tissue in the lungs and abnormal breathing. There are variations of hypersensitivity pneumonitis which depends on the occupation, including the cork worker's lung, farmer's lung, and also the mushroom worker's lung.

• Emma Bullock
• 16/06/2009, 6:59 PM
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