Prospective evaluation of World Health Organization criteria to assist diagnosis of tuberculosis in children
Because of the difficulty in confirming childhood tuberculosis (TB), the World Health Organization (WHO) proposes a hierarchical approach to diagnosis using history and certain clinical features to help to improve the control of TB in communities. The objective of this study was to evaluate prospectively in children the diagnostic value of recent weight loss or failure to gain weight adequately, cough or wheezing for >2 weeks and recent household contact with an adult case of pulmonary TB. These evaluations were performed in 627 children presenting to the paediatric outpatient department of a tertiary hospital situated in the Western Cape Province of South Africa and serving a community with a very high incidence of TB (>1,000 per 100,000). If at least one of the criteria was present, the diagnosis of TB was investigated further by clinical investigation, Mantoux test, chest radiography and TB culture from gastric aspirate. One or more of the proposed criteria for diagnosing TB in childhood were present in 206 children (33%). TB confirmed by culture of Mycobacterium tuberculosis from gastric aspirate was found in 10 children (5%). After diagnostic work-up, 23 children (11%) were considered to have probable TB, whereas 173 (84%) were, after follow-up of 8 weeks, thought not to have TB. In this study the simultaneous presence of the three WHO criteria for suspecting TB had a positive predictive value of 63%. These results should assist in the more precise delineation of the predictive value of the proposed World Health Organization approach to the diagnosis of tuberculosis in childhood.