LAUSR

Childhood tuberculosis (TB) remains a major concern in many developing countries, representing a prominent cause of morbidity and mortality in these regions. The World Health Organization estimates that at least 500 000 children become infected, and approximately 70 000 die each year with children younger than 2 years being at greatest risk for disease progression. This being said, in the United States, there are only 500 newly diagnosed cases per year in children making diagnosis and management of this disease uncommon for the general pediatrician and primary care physician in the United States. Mortality is less than 1% except in children with congenital and neonatal TB where the mortality is approximately 50%. Latent TB infection (LTBI) treatment is the main strategy for treating TB, but to achieve this, reliable testing methods are required, especially for groups at high risk for the disease. Recognition of potential TB disease and diagnosis in children has been particularly difficult as early signs and symptoms are subtle. Pneumonia unresponsive to antibacterial therapy, fever of unknown origin, scrofula, and abdominal pain are the most frequent presentations. In adults, the diagnosis of Mycobacterium tuberculosis is based on clinical features, an abnormal chest radiograph, sputum containing acid-fast organisms, and most important, a positive culture. The tuberculin skin test (TST) was the standard screening test in the past, but this has been largely replaced by a interferon-gamma release assay (IGRA) for adults. Major problems with the TST have been differing strengths and types of purified protein derivative (PPD) used, variability in administration and reading of test results and differences in the interpretation of skin test induration responses. Other confounding variables include infection with nontuberculous mycobacterial organisms and the previous administration of the bacille Calmette-Guerin (BCG) vaccine.