Minimal Tuberculosis

Abstract

The diagnosis of pulmonary tuberculosis by roentgenographic examination, particularly in routine and mass chest x-ray surveys, has become a common practice. This is especially true as regards minimal lesions, where it is admitted that laboratory and clinical findings are often absent or inadequate to help in early diagnosis. Since basic criteria for the determination of the clinical significance of the minimal lesion have not been established, it has become an increasingly frequent custom of chest physicians and roentgenologists to attempt to read from the film the clinicopathologic nature of the lesion for the purpose of proper disposition. The terms used in the roentgenologic description of minimal tuberculous lesions imply a certain pathologic significance for each type of infiltration, i.e., exudative, exudative-productive, productive-fibrotic, and fibro-calcific, Reisner and Downes (1) have provided the following excellent definitions for the roentgenologic character of the infiltration: “Exudative: Roentgenologically, the density usually shows rather ill-defined borders; occasionally it may be well circumscribed; it is ‘soft’ in appearance, either round or irregular in shape. The size is variable, usually ranging from one to two or three centimeters in diameter. The individual lesion may represent either a single focus or it may be composed of several smaller confluent densities. The intensity of the shadow depends on the size of the lesion, it may be either homogeneous or flocculent in appearance. “Productive and Fibrotic: From the roentgenological appearance a distinction may be made between two main forms, namely: (a) discrete nodular densities, usually multiple, of small size, showing well defined borders, ‘hard’ in appearance, either round or irregular in shape; (b) strand-like or linear densities, sharply outlined, often irregular in shape and distribution. The majority of the cases included in this category present a combination of form ‘a’ and ‘b’. “Exudative-Productive: This form may be regarded as an intermediate group between the two preceding types, the roentgenological findings presenting a combination of the features of both the exudative and productive-fibrotic elements in varying proportions. “Fibre-Calcific Form: Roentgenologically, the changes consist of sharply defined nodular densities, showing either round or irregular borders. The nodules are usually multiple; their distribution is scattered; they are generally of small size, measuring several millimeters in diameter, only rarely exceeding one centimeter. The intensity of the shadows is of a type usually interpreted as characteristic of calcium deposition. Such findings often occur in combination with changes indicative of strand-like and linear fibrosis.” In a recent study (2) we attempted to determine the clinical significance and prognosis of minimal pulmonary tuberculosis in a group of 220 sanatorium cases.