[Primary respiratory tuberculosis in children: Hyperdiagnosis or hypodiagnosis]

The diagnosis of bacteriologically negative tuberculosis (TB) in children is traditionally based on clinical criteria, such as a history of contact with a patient with TB, a positive tuberculin test suggesting TB infection and radiological TB changes. To improve the early diagnosis of TB, the authors applied computed tomography (CT) to 284 children with suspected TB (a study group) who had negative bacterial tests and normal chest X-ray films. To identify individual diagnostic criteria, the study group was divided into 4 subgroups: 1) 119 patients with positive tuberculin tests (> or = 10 mm induration) and a known contact with a TB patient; 2) 100 patients with positive tuberculin tests (> or = 10 mm induration) without known contact with a TB patient; 3) 33 patients with negative tuberculin tests (> or = 10 mm induration) and a known contact with a TB patient; 4) 32 patients with negative tuberculin tests (> or = 10 mm induration) without known contact with a TB patient. A control comprised 29 children with bacteriologically verified TB and normal chest X-ray films. Conventionally radiological studies revealed undiagnosed lung parenchymal abnormalities in 35 (29.4%), 16 (16.0%), 4 (12.1%), and 5 (15.6%) children in Subgroups 1, 2, 3, and 4, respectively, and in 11 (37.9%) children in the control group. Intrathoracic lymph nodes of > or = 5 mm were rarely diagnosed in all the groups of patients, including children with bacteriologically verified TB. Calcified lymph nodes were visualized in 62 (52.1%), 40 (40.0%), 18 (54.5%), and 7 (21.9%) children in Subgroups 1, 2, 3, and 4, respectively, and in 15 (51.7%) children in the control group. CT revealed an active TB process in 49 (41.2%), 23 (23.0%), 12 (35.4%) and 1 (3.1%) children in Subgroups 1, 2, 3, and 4, respectively. The findings demonstrated the hypodiagnosis of active TB in the infected children contacting a TB patient when CT is not applied.