Mountain desert silicosis.

Objectives: To evaluate the radiological miliary shadows in the high landers of a Himalayan desert for the presence of silicosis.

Methods: Seventeen high landers attending the Medicine OPD of a multi-speciality medical camp at Kaza in Himalayas (height 12,500 feet above sea level) having radiological miliary shadows were included in the study. A detailed life time work place history was taken. In the laboratory workup their hemogram, repeat chest skiagram, peak expiratory flow rate, urinalysis and electrocardiogram were undertaken. Their localities were looked for the presence of industries particularly for silicosis prone work place. The silica contents of upper strata of soil were estimated.

Results: Silicosis--chronic simple variety was present in nine males and eight females. The youngest person was 43 years of age and oldest person was of 65 years of age. There was no silicosis prone industry in their locality. Four had taken repeated courses of anti-tubercular treatment in adequate doses for these miliary shadows without any change in the radiological shadows. Three had silicosis prone work history. Seven were smokers and two had hypertension. The miliary shadows were 2-4 mm in size and hilar lymphadenopathy was in 11 and fine calcification of lymph nodes in two. Peak expiratory flow rate was reduced. Upper strata of soil had a silica content of 36.8 percent.

Conclusion: Silicosis developed in high landers of the Himalayas even without working in silicosis prone work place. They were exposed to silica from the non-work place silica rich environment.