Exogenous reinfection appears to be a major cause of postprimary tuberculosis after a previous cure in an area with a high incidence of this disease. This finding emphasizes the importance of achieving cures and of preventing anyone with infectious tuberculosis from exposing others to the disease.

There is a critical need for improved diagnosis of tuberculosis in children, particularly in young children with intrathoracic disease as this represents the most common type of tuberculosis in children and the greatest diagnostic challenge. There is also a need for standardized clinical case definitions for the evaluation of diagnostics in prospective clinical research studies that include children in whom tuberculosis is suspected but not confirmed by culture of Mycobacterium tuberculosis. A panel representing a wide range of expertise and child tuberculosis research experience aimed to develop standardized clinical research case definitions for intrathoracic tuberculosis in children to enable harmonized evaluation of new tuberculosis diagnostic technologies in pediatric populations. Draft definitions and statements were proposed and circulated widely for feedback. An expert panel then considered each of the proposed definitions and statements relating to clinical definitions. Formal group consensus rules were established and consensus was reached for each statement. The definitions presented in this article are intended for use in clinical research to evaluate diagnostic assays and not for individual patient diagnosis or treatment decisions. A complementary article addresses methodological issues to consider for research of diagnostics in children with suspected tuberculosis.

One of the obstacles in discussing childhood tuberculosis (TB) is the lack of standard descriptive terminology to classify the diverse spectrum of disease. Accurate disease classification is important, because the correct identification of the specific disease entity has definite prognostic significance. Accurate classification will also improve study outcome definitions and facilitate scientific communication. The aim of this paper is to provide practical guidelines for the accurate radiological classification of intra-thoracic TB in children less than 15 years of age. The proposed radiological classification is based on the underlying disease and the principles of pathological disease progression. The hope is that the proposed classification will clarify concepts and stimulate discussion that may lead to future consensus.

Pulmonary tuberculosis can be diagnosed with a reasonable degree of accuracy in HIV-uninfected children using a simple symptom-based approach. This offers the exciting prospect of improving treatment access for children, particularly in resource-limited settings where current access to antituberculosis treatment is poor.