Pneumoconioses

Pneumoconioses 

a group of lung diseases, classified as occupational diseases, caused by prolonged inhalation of industrial dust and characterized by the development of fibrosis. The term “pneumoconiosis” was first proposed in 1866 by the German physician F. von Zenker. The disease occurs in workers in the mining, coal, machine-building, and some other branches of industry. Several types of pneumoconiosis are distinguished, based on the composition of the inhaled dust: silicosis, caused by the inhalation of dust containing a large quantity of free silicon dioxide (SiO2); silicatosis, caused by the dust of silicates—substances containing silicon dioxide and other elements, such as aluminum or magnesium; asbestosis, caused by asbestos dust; pulmonary talcosis, caused by talc dust; anthracosis, caused by coal dust; siderosis, caused by iron dust; and silicoanthracosis, caused by mixed dusts of silicon dioxide and coal. Other pneumoconioses include byssinosis and bagassosis.

Pneumoconioses are chronic diseases that usually develop slowly; acute pneumoconiosis is rare. The course of the disease depends on the working conditions, such as the concentration of dust in the air in the work area and the composition of the dust; on the presence of concurrent diseases, especially diseases of the respiratory tract, including tuberculosis, and the cardiovascular system; and on individual sensitivity. The clinical symptoms vary with the form of pneumoconiosis, although all forms have some symptoms in common. Several stages of the disease are distinguished according to the degree of fibrosis present. Initially there is pain in the chest and a dry cough. Subsequently, symptoms of insufficiency in the lungs appear, which may be accompanied by evidence of cardiac insufficiency as a result of the development of cor pulmonale. The mucous membranes of the respiratory tract often undergo changes, such as atrophy or hypertrophy, and gastric, pancreatic, and metabolic functions are impaired. Complications include pneumonia, tuberculosis (called silicotuberculosis), chronic bronchitis, and bronchiectasis. The diagnosis is based on various factors, including the length of time the patient has been in contact with industrial dust, the dust’s composition, specific working conditions, and previous history of respiratory disease.

Treatment is directed mainly at reducing and eliminating the deposition of dust in the lungs, suppressing allergic tissue reaction to the dust, increasing resistance, and improving lung ventilation, blood circulation, and metabolism. Breathing exercises and dietotherapy are prescribed, as well as agents to relieve bronchospasms, cardiovascular and antibacterial preparations, oxygen, vitamins, and in some cases corticosteroid hormones. Treatment at a tuberculosis dispensary is recommended for patients with silicotuberculosis. Sanatorium treatment is provided at local climatic health resorts; in cool weather such treatment is available on the southern coast of the Crimea, in the Northern Caucasus, at the Borovoe resort, and elsewhere. Prophylaxis includes control of dust in the air of the work area, which is a task of occupational hygiene, preliminary medical examinations for new workers, and periodic medical examinations for those already on the job. Patients should be transferred to work that does not involve contact with dust in order to prevent further development of fibrosis.

REFERENCE

Professional’nye bolezni, 3rd ed. Edited by A. A. Letavet. Moscow, 1973. (Bibliography.)

N. N. SHATALOV