They indicate that transmission of tuberculosis has occurred recently. Many adults who develop active tuberculosis were infected many years ago, when their immune systems were stronger and able to protect them. Children, particularly infants, could have been infected only recently because of their age. When a child is diagnosed with active tuberculosis, it means that someone close to them, almost always an adult, must have active tuberculosis and is possibly transmitting the disease to others as well. Diagnosis of tuberculosis in children is difficult and poses problems that are not present in adults.
Children are less likely to have obvious symptoms of tuberculosis.
In addition, sputum samples are difficult to collect from children. Culture and drug susceptibility results from tests of the adult source case often have to be relied upon for diagnosing and properly treating tuberculosis in a child. Tuberculosis in infants and children younger than 4 years of age is much more likely to spread throughout the body through the bloodstream. In addition, children are at much greater risk of developing tuberculous meningitis, a very dangerous form of the disease that affects the central nervous system. For these reasons, prompt diagnosis and immediate treatment of tuberculosis are critical in pediatric cases.