Diagnosis of pulmonary tuberculosis in children--what's new?

However, evidence suggests that in developing countries, where most disease occurs, childhood TB constitutes a large proportion of the TB caseload, contributing approximately 15 - 20% of all cases. The burden in children and impact on child health has been under-recognised, partly because of difficulties in confirming the diagnosis. Diagnostic confirmation may be difficult because of many factors including nonspecific clinical signs, coexisting malnutrition, variable interpretation of chest radiographs, paucibacillary disease, difficulty in obtaining specimens for culture and relatively low rates of bacteriological confirmation. As a result diagnosis in children has relied mainly on clinical case definitions, tuberculin skin testing and chest radiography. 2 Diagnostic uncertainty has been compounded by the HIV epidemic in which chronic lung disease, anergy, coexisiting malnutrition and nonspecific clinical and radiological signs make definitive diagnosis even more challenging. The consequences of undiagnosed or untreated paediatric TB are especially serious as children are more likely to develop miliary or severe disease. Furthermore cases of childhood TB frequently reflect an undiagnosed adult infectious source case; therefore the occurrence of TB in children frequently indicates failure of a TB control programme. Moreover, definitive diagnosis and microbiological confirmation have become increasingly important in the era of multidrug-resistant TB (MDR) and extremely extensively drug-resistant TB (XDR). This review considers currently available and new diagnostic methods for pulmonary TB (PTB). Current methods have relied predominantly on clinical case definitions, tuberculin skin testing and chest radiography. Newer methods include improved specimens and microbiological methods, immune testing, especially gamma-interferon assays, phage-based tests, polymerase chain reaction and antigen detection.