The Primary Lung Focus of Tuberculosis in Children.
Of 1,800 consecutive autopsies on children whose ages ranged from a few hours to between 12 and 13 years, and who lived in Glasgow and the West of Scotland, 283 (15.7%) were found to have tuberculous lesions.-Of the total tuberculous cases, the lungs or tracheo-bronchial lymph nodes were the seat of tuberculous lesions in 173 (61.1%), and of these 168 (97.1%) died as a result of the tuberculous disease.-A primary lung lesion was found in 148 of the cases classified as having the primary site of infection in the thorax. The primary lung lesion consisted of a localized patch of caseous broncho pneumonia and in the great majority of cases was single. Calcification of these lesions was unusual and only about one-third showed evidence of surrounding fibrosis, the incidence of which increased with the age of the children.-Most of the primary lung lesions were subpleural in position and the right lung was more often the seat of such lesions than the left; the right upper lobe being most frequently involved and then, in order, the right lower, left upper, left lower, and right middle.-The tuberculous adenitis in the tracheo-bronchial glands was related both anatomically and pathologically to the primary lesion in the lungs, the involvement of the glands being secondary to the lung lesion.-In 25 of the cases considered as primary thoracic infections, no primary lung lesions were found.-In a series of cases in which the type of infection was investigated, 173 human and 3 (2.7%) bovine strains were found in cases with the primary site of the infection in the thorax.-Only human strains were obtained from cases with primary lung lesions.-These findings were in marked contrast to those found in children in the same series with the primary site of infection in the abdomen where 81.8% of the infecting bacilli were of the bovine type, and also in cases of bone and joint tuberculosis-a blood-borne infection, in which 34.6% of the causal organisms were bovine strains.-From the pathological and bacteriological evidence, it is concluded that the focus described as the primary lung lesion is indeed such, and that it is due to direct infection of the lungs through the air passages.
Blacklock
J W
JW