Tuberculosis in International Adoptees

What should I do if my child is diagnosed with tuberculosis?

Tuberculosis is an infection caused by the bacterium Mycobacterium tuberculosis, which differs in many ways from the bacteria that cause other childhood infections such as otitis or tonsillitis. Because of these differences, the usual antibiotics prescribed for simple childhood infections are not effective in tuberculosis.

Children are exposed to tuberculosis when they inhale the contagious sputum droplets of an infectious contact (usually an adult in their environment). These sputum droplets are spread by coughing, laughing, or even singing, so it is not difficult to see why infected adults, who can typically generate a more vigorous cough, are considered highly contagious and young infants are not. In populations where TB is endemic, infected adults may work in orphanages or nurseries or be part of a foster family. In other circumstances, TB may be passed from an infected mother to her child immediately after birth. These children are often extremely ill and many do not live beyond the early days of infancy, especially if poor nutrition and lack of medical care contribute to the severity of illness.

In TB infection, the usual focus is the lung, but untreated TB may spread more widely. For these reasons, the symptoms of TB may range from the relatively healthy child with mild wheezing or coughing to the more severely affected child with widespread disease involving the brain, lungs, bones, or kidneys. Children with very poor nutritional status and children who acquire TB very early in life are at increased risk for widespread disease.

After exposure to tuberculosis, the body's immune system develops a delayed hypersensitivity response, which is reflected in a positive TB skin test. The skin test remains positive even after appropriate treatment for TB. Thus, a positive TB skin test may mean either a previous exposure (infection without active disease), the presence of the actual disease, or a past infection that is now cured. Differentiating between these possibilities is clearly very important.

All adopted children from abroad, whether they appear healthy or ill, should receive the Mantoux (needle prick) intradermal skin test for tuberculosis. This test, known as a PPD, is more sensitive and specific than the multiple puncture test (Tine). Undernourished children may fail to respond to the Mantoux test even though they may have been exposed to TB. This type of negative reaction is called anergy and is related to the inability of the immune system to respond appropriately to the skin test. One way to control for the possibility of anergy is to place a Candida (yeast) skin test at the same time the Mantoux test is given. In children whose immune system is appropriately active, the Candida skin test will be positive, and a negative Mantoux test will then accurately reflect the child's never having been exposed to TB. Depending on the country of origin, 3-9% of international adoptees will have a positive skin test.

See also, BCG and Subsequent Tuberculosis Testing