Tuberculosis in Children
The natural history and clinical expression of infection due to Mycobacterium tuberculosis differ substantially in children compared with adults. The natural history depends upon the age at infection and the host immune status. Children infected prior to age 4 have a very high rate of developing immediate clinical or radiographic manifestations or both, but are unlikely to develop reactivation disease in adulthood. In contrast, children infected in preadolescence or adolescence are more prone to developing more severe adult-type pulmonary tuberculosis soon after infection or in adulthood. It is difficult to confirm the diagnosis of tuberculosis by current microbiological methods. Even in industrialized countries, the triad of a positive tuberculin skin test, radiographic and/or clinical manifestations consistent with tuberculosis, and establishing a recent link to a known infectious case of tuberculosis is the "gold standard" for diagnosis. Children with tuberculosis respond well to and tolerate the same basic treatment regimens as used for adults. Some prevention of childhood tuberculosis can be achieved by the use of the bacille Calmette-Guérin (BCG) vaccines, but the use of chemotherapy to treat recent tuberculosis infection, discovered via contact tracing, is of paramount importance even when BCG vaccines are used.

Tuberculosis remains one of the major diseases afflicting children throughout the world. Although the exact number of annual cases of childhood tuberculosis is unknown, the World Health Organization (WHO) has estimated approximately 1 million new cases and 400,000 deaths per year in children due to tuberculosis. Many of these cases go undiagnosed and untreated and many of these children could be salvaged if there were improvements in diagnosis and treatment available for children.

Many experts in childhood tuberculosis feel that children have been neglected in the worldwide effort to control tuberculosis. There are many reasons for this including the fact that most children with tuberculosis are not infectious and therefore not considered to be as important as adults with contagious tuberculosis, the frustration at the difficulty in establishing a microbiological diagnosis of tuberculosis in children, and the relative neglect of pediatricians and researchers in studying childhood tuberculosis. In fact, there is a rich scientific literature about childhood tuberculosis supporting simple practices, which, if adequately put into place, would greatly improve the ability to diagnose and treat children with tuberculosis.

A comprehensive description of childhood tuberculosis is beyond the scope of this article. Instead, this article concentrates on the special aspects of tuberculosis diagnosis, treatment, and control that are particularly salient to the study of childhood tuberculosis.