PNEUMOCONIOSIS, ITS EPIDEMIOLOGY, PREVENTION AND CONTROL.

WHAT IS PNEUMOCONIOSIS?

A lung disease due to exposure of lung for variable period to dust in the size range of 0.5 to 3 microns leading to lung fibrosis and other complications.

Chemical composition

Fineness

Concentration of dust in air

Health status of the person exposed

Period of exposure

HAZARDS OF DUST PARTICALS ON LUNG DEPENDS ON

SILICOSIS

ANTHRACOSIS

BYSSINOSIS

BAGASOSIS

ASBESTOSIS

FARMAR’S LUNG

SOME IMPORTANT DUST DISEASES ARE:

SILICOSISMajor cause of permanent disability and mortality

First reported in India from Kolar Gold Mines (Mysore) in 1947

The incubation period may vary from a few months to up to 6 years of exposure.

Silicosis was made a notifiable disease under the Factories Act 1948 and the Mines Act 1952

Particles reach lungs

Ingested by phagocytes

Dense nodular fibrosis

Respiratory problems

Pathogenesis of silicosis

Courtesy of Dr. John Godleski, Brigham and Women’s Hospital, Boston, Massachusetts.)

Advanced silicosis seen on transection of lung. Scarringhas contracted the upper lobe into a small dark mass (arrow). Note thedense pleural thickening.

Symptoms of silicosis

Management of silicosis:

There is no effective treatment of silicosisFibrotic changes that have already taken place cannot be reversed.The only way that silicosis can be controlled is bya)Rigorous dust control measures, e.g.,

substitution complete enclosure , isolation , hydroblasting etc

b)Regular examination of workers

Anthracosis•Risk of death among coal miners has been nearly twice that of general population

•It has been declared as a notifiable disease in Indian Mines Act of 1952 and also compostable in the Workmen’s Compensation Act of 1959.

Pathogenesis of anthraconiosis

Progressive massive fibrosis in a coal worker. Largeamount of black pigment is associated with fibrosis.(From Klatt EC: Robbins and Cotran atlas of pathology, ed 2, Elsevier, p. 121.)

BYSSINOSIS•Due to inhalation of cotton fibre dust over

long periods of time

•Symptoms are chronic cough , progressive dyspnoea, ending in chronic bronchitis and emphysema

•Incidence of byssinosis is reported to be 7 to 8 percent in three independent surveys carried out in Mumbai, Ahmedabad and Delhi.

Bagassosis•Due to bagasse or sugarcane•Reported first by Ganguli and Pal in 1955 in a cardboard manufacturing firm near Kolkata .

Infection of Thermoactinomyces sacchari

Acute diffuse bronchiolitis

Diffuse fibrosis, emphysema and bronchiectasis

ASBESTOSISAsbestos are silicates of varying composition ; the silica combines with such bases as magnesium, iron, calcium, sodium and aluminium.Asbestos are of two types

a)Serpentine or chrysolite varietyb)Amphibole type

Asbestos is mined in Andhra Pradesh, Bihar, Jharkhand, Karnataka etc

Asbestos enter via inhalation

Fine dust deposited via alveoli

Pulmonary fibrosis

Respiratory insufficiency and death, carcinoma of bronchus , pleura, peritoneum and gut.

Preventive measures

a)Use of safer types of asbestos

b)Substitution of other insulants; glass fibers, mineral wool, calcium silicate etc

c)Rigorous dust controld)Periodic clinical

examination

Farmer’s lungDue to inhalation of mouldy hay or grainsG

rain dust or hay with moisture

Bacteria and fungus grow

Infection of Micropolyspora faeni

Pulmonary fibrosis and cor pulmonale

REFERENCE: PARK’STEXTBOOK OF PREVENTIVE

ANDSOCIAL MEDICINE

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