Tuberculosis (TB) is caused by bacteria, Mycobacterium tuberculosis, which is spread through the air. This can occur when a person with pulmonary TB disease coughs or sneezes. When a person has contact with an individual with active, contagious TB disease, three outcomes are possible. First, the bacteria may not enter their body. Second, the bacteria can enter their body and not cause illness; this is termed TB infection. Third, the bacteria can enter their body and cause illness months to years later; this is termed TB disease.
Definitions used for Childhood TB:
TB Exposure: Children who have been around a person with possible active TBdisease have been exposed to TB. These children do not have symptoms of TB and have a negative chest x-ray and a negative tuberculin skin test (TST, PPD). Older children with tuberculosis just need another skin test about 2 months after the first skin test. However, young children are at high risk of becoming sick with TB disease. Consequently, we recommend starting young children with TB exposure on one medication to prevent them from becoming sick. If the second skin test is also negative, we can stop the medication, but in the meantime, the child is protected. Children with TB exposure are not contagious and do not need to have their activity restricted because of being exposed.
TB Infection: Children with TB infection have no symptoms and a normal chest x-ray, but they have either a positive tuberculin skin test (TST, PPD) or a positive blood test for TB (interferon gamma release assay, IGRA). This means the child has inhaled the bacteria causing TB , and the child is at risk for becoming sick with TB disease in the future. This lifetime risk can be reduced by giving one medication, usually for 9 months. Children with TB infection are not contagious and do not need to have their activity restricted because of being infected.
TB Disease: Children with TB disease have symptoms of TB (such as fever, cough, weight loss, or other symptoms) and/or have a chest x-ray that is not normal. The most common sites of disease in children are the lungs and lymph nodes. Treatment for children with TB disease consists of 3 or more medications given to the child by the health department or a health department/TB program designee. The treatment duration usually is 6-12 months, depending on the site of disease. Children who have TB disease caused by drug-resistant organisms may require more drugs and a longer course of therapy.