Tuberculosis Screening in the Internationally Adopted Child
Tuberculosis is an infection caused by the bacterium Mycobacterium tuberculosis, which differs in many ways from the bacteria that cause other childhood infections. Because of these differences, the usual antibiotics prescribed for simple childhood infections are not effective.
Children are exposed to tuberculosis when they inhale the contagious sputum droplets of an infectious contact – usually an adult caregiver. These sputum droplets are spread in many ways; coughing, singing, and laughing to name just a few. It is not difficult to see why infected adults, who can typically generate a stronger cough, are considered highly contagious and children are not.
TB is endemic in most countries placing children in the United States at increased risk. Infected adults may work in orphanages or nurseries or be part of a foster family. In other settings, TB may be passed from an infected mother to her newborn. These children are often extremely ill and many do not live beyond early infancy, especially if there is poor nutrition or lack of medical care.
In TB infection, the usual area of focus is the lung, but untreated TB may be widespread. For this reason, the symptoms of TB may range from the relatively healthy child with mild wheezing or coughing to the more severely affect child with disease involving the brain, lungs, kidneys or bones. Children with very poor nutrition and those who acquire TB 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 Mantoux test (PPD). The skin test remains positive even after appropriate treatment. Thus, a positive 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 children adopted from abroad should receive the Mantoux intradermal skin test for TB. This test, known as a PPD, is more sensitive and specific than the previous multiple puncture test.
Depending on the country of origin, up to 10 percent of international adoptees will have a positive skin test. Some experts say this value may be higher. The immune system may require up to 3 months to respond after an initial TB exposure. If your child has symptoms consistent with TB and the initial PPD is negative, testing should be repeated within 6 to 12 weeks. In some countries, BCG, a vaccine made from a weakened strain, is used to prevent the spread of TB. Most children from Eastern Europe and China have been vaccinated (there usually is small scar on the left shoulder). Unfortunately, this vaccine, administered at birth, does not offer complete protection. Individuals who have been vaccinated with BCG can still be infected with tuberculosis.
There have been numerous discussions revolving around TB testing after a child has received the BCG vaccine. For example, some feel that because your child was immunized with BCG, the TB testing cannot be performed or that the BCG can be responsible for a “positive” reaction. The AAP has now advised physicians that children who have received BCG vaccination can be screened with a Mantoux test. Interpretation of the test is the same as in non-immunized children. Positive Mantoux reactions of 5 mm or greater in an HIV-infected child or 10 mm or greater in the HIV-negative child should be evaluated. Your physician should obtain an appropriate history, perform a complete physical examination and obtain a chest x-ray. After this has been done, the results of the history, physical examination, chest x-ray, and sputum cultures if necessary will be used to determine the possibility of active tuberculosis or simple exposure (infection without active disease).
Because many physicians in the United States have not encountered TB, consultation with an infectious disease specialist or physician experienced in International Adoption Medicine is recommended for any child whose PPD test is positive. The physician will review the evidence for the diagnosis, determine an appropriate course of drug therapy, supervise treatment and counsel the family.
Written By Nicholas Rogu M.D. of Adoptiondoctors.com and Adoptioneducationclasses.com, He is a general Pediatrician with a Special Interest in children with Developmental Disabilities.