[Should pulmonary computed tomography be performed in children with tuberculosis infection without apparent disease?]

During early childhood, in particular, there is a continuum between tuberculosis infection and disease. When establishing the diagnosis in a child with suspected tuberculosis, the distinction between infection and disease frequently depends on the interpretation of the chest X-ray. Some studies have shown hilar and mediastinal lymphadenopathies on computed tomography (CT) in children with tuberculosis infection without apparent disease, i.e., asymptomatic children with a positive tuberculin skin test and normal chest X-ray. These observations raise the issue of whether pulmonary CT should be performed in children with tuberculosis infection without apparent disease and whether different types of therapy should be administered depending on the results.

We reviewed the physiopathology of tuberculosis infection and disease, diagnostic methods and treatment, and the literature on the use of pulmonary CT scan in pediatric tuberculosis.

Modern CT scanners indicate hilar and mediastinal lymphadenopathies in many of the children with tuberculosis infection with no apparent disease on chest X-rays. However, neither the size nor the morphology of these adenopathies allows active tuberculosis to be diagnosed. The natural history of childhood tuberculosis indicates that most children show hilar lymphadenopathies after the primary infection, although progression to disease is rare and is characterized by the presence of clinical symptoms. The exceptions are children younger than 4 years old and those with immune alterations who more frequently show progression of infection to disease and who require close follow-up. In addition, the experience accumulated over many years in the treatment of tuberculosis infection with isoniazid has shown this drug to be effective in both short- and long-term prevention of active disease. Official guidelines and expert opinion do not recommend systematic pulmonary CT scan in these children or modification of treatment according to the results.

Hilar and mediastinal lymph nodes are frequently found in the CT scans of children with tuberculosis infection without apparent disease but there is no evidence that these adenopathies indicate active disease or that these children require different treatment. Consequently, until demonstrated otherwise, pulmonary CT scanning and changes in chemoprophylaxis are not justified in children with tuberculosis infection.