Partnering to solve the problem of tuberculosis.

Abstract

Tuberculosis (TB) is a major global health problem and the burden remains enormous. In 2012, an estimated 8.6 million people developed TB (13% with human immunodeficiency virus [HIV] co-infection) and 1.3 million died from the disease [1]. Most cases were in the Southeast Asia, Africa and Western Pacific regions [1]. About 3.6% of newly diagnosed TB cases and 20% of people previously treated for TB have multidrug-resistant TB [1]. Among children younger than 15 years, there were an estimated 530,000 TB cases and 74,000 TB deaths in 2012 [1]. Children with pulmonary tuberculosis present with nonspecific respiratory symptoms, which are hard to differentiate from other causes, posing a diagnostic challenge. A culture is the definitive diagnostic tool but not routinely attempted because children do not produce enough sputum for examination. A positive tuberculin skin test suggests infection but cannot differentiate quiescent from active disease state, and a negative test does not exclude TB. XpertMTB/RIF, which is a rapid molecular diagnostic test, has been endorsed by the World Health Organization (WHO) and is rapidly being adopted in various countries for detection of mycobacterium TB (MTB), including rifampicin-resistant types (RIF) [1, 2]. In children, Xpert MTB/RIF has been found to be more sensitive than smear microscopy, but a negative test does not exclude a diagnosis of pulmonary TB; the test is unable to identify 20–25% of children with culture-confirmed TB [3, 4]. The generally low mycobacterial load in respiratory samples of children seems to be a limiting factor for assays, including MTB/RIF [5]. It is also important to identify TB infection and disease among HIV-infected children. This helps in the medical decision-making and management, which includes initiation of antiretroviral therapy and isoniazid preventive therapy. Optimal use of available diagnostics improves active case detection, but there remains an urgent need to develop cheaper and more sensitive point-of-care diagnostic tests, particularly for younger children. Medical imaging methods are important for the diagnosis and thorough evaluation of TB, which have important treatment implications. The chest radiograph is mostly used because of its wide availability and instantaneous result. A normal chest radiograph cannot exclude presence of pulmonary TB but when positive the findings, although nonspecific, closely reflect the pathological changes of the disease (Figs. 1, 2, and 3). It can help assess complications associated with TB and also detect other underlying pathology, including TB–HIV co-infection. Other important considerations include imparting radiation dose to patient, variability of technique, changing pattern of disease, identification of drug resistance, and inter-observer variability. The World Federation of Pediatric Imaging (WFPI) seeks to create an impact in the global fight against childhood tuberculosis through the use of radiography in low-resource settings. WFPI supports the conversion of existing facilities to digital imaging with operator guidelines and recommendations on radiation safety. Training and education on TB imaging is emphasized and delivered through site visits, regional training exchanges, international training courses and webinars. The WFPI Web site has instructional videos and lectures available on the interpretation of chest radiographs in childhood tuberculosis [6–8]. Although more radiologists in low-resource settings are being identified and trained, WFPI has made it possible for on-site radiologists and radiographers B. F. Laya (*) St. Luke’s Medical Center – Global City, 32nd Street Bonifacio Global City, Taguig City, Philippines 1634 e-mail: Bernielaya@gmail.com