The natural history of childhood intra-thoracic tuberculosis: a critical review of literature from the pre-chemotherapy era.

The pre-chemotherapy literature documented the natural history of tuberculosis in childhood. These disease descriptions remain invaluable for guiding public health policy and research, as the introduction of effective chemotherapy radically changed the history of disease. Specific high-risk groups were identified. Primary infection before 2 years of age frequently progressed to serious disease within the first 12 months without significant prior symptoms. Primary infection between 2 and 10 years of age rarely progressed to serious disease, and such progression was associated with significant clinical symptoms. In children aged >3 years the presence of symptoms represented a window of opportunity in which to…