A variety of organic or inorganic dusts can directly cause lung diseases either through direct inhalation or due to allergy. This occurs in occupations involving chronic inhalation of the dust or fumes or spores or allergy to them.

Farmers working in the fields, mine workers, those handling birds, workers in textile mills, all these are at high risk of developing these diseases which are collectively called, "occupational lung diseases”.

The sources of the disease are many. It can be exposure to mouldy hay, straw or grains, droppings of birds, mouldy cheese or other kinds of fungal growth, producing allergy. In mines and stone quarry, chronic lung disease can develop due to chronic exposure to dust of different kinds. Stone quarry workers are also at similar risk of developing chronic lung diseases.

Whatever maybe the source, the disease gradually causes damage to the lungs in many ways, thus incapacitating the person for physical work. In the early stages, there are symptoms of headache, muscle pains, dry cough and breathlessness whenever the person is exposed to the offending substance. It has been aptly said to be a, "Monday morning sickness”, to describe the sickness which keeps away on week ends to return on weekdays. But in the later stages, the symptoms become chronic. The affected person gets breathless on exertion. The amount of exertion producing breathlessness becomes less and less to the extent that one becomes breathless even on resting. Breathlessness is often accompanied by cough with mild or moderate mucoid expectoration.

There is closure of the airways and alveoli (air sacs), permanently in contrast to bronchial asthma, wherein after the offending allergy producing substance is removed, airways open up and the person gets relief. There is damage to the lung tissue in patches or whole and they are replaced by fibrous tissue. This impedes good ventilation which further contributes to the breathlessness and suffering.

The problems are further aggravated by smoking, which also contributes to inhalation of fumes and carbon.

Occupational history of the affected person, a high degree of suspicion, X-ray and C.T. scan of the chest and lung function tests help to determine the diagnosis.

These people are more prone to develop infections in the lungs like pneumonias and tuberculosis. The chronic lung disease can also predispose to cancer of the lung, particularly in those working with asbestos.

Thus these poor people are caught in a vicious never ending trap. They develop a chronic illness due to the work which deprives them of their capacity to work. Once a worker develops a chronic occupational lung disease, there is no total cure available. Bronchodilators provide mild relief in breathlessness. Antibiotics can take care only of the infection, but not of the damage to lungs. Steroids do provide relief in the symptoms. But when used for long time, tend to produce undesirable side effects.

The best management of occupational lung diseases lies in prevention. The workers should be given information about these diseases by responsible members of the society like their employers, supervisors and doctors. They should be advised to keep their mouths and noses covered while working. Abstinence from smoking and alcohol and good personal hygiene are very important measures to keep lungs healthy. Good nutritious food also aids in building up the resistance of an individual. Breathing exercises are very helpful in maintaining good lung function in face of damage to lung tissue. When symptoms of the disease develop, they should be treated at the earliest and due precautions then observed. This may help to prevent further progression of the illness. Prevention of occupational lung diseases will help enhance the productivity of the society.

Dr Rachna Pande, Specialist, internal medicine