Fine needle aspiration biopsy: an undervalued diagnostic modality in paediatric mycobacterial disease.

Mycobacterial disease, and particularly tuberculosis (TB), is an escalating problem in developing countries, fuelled by the parallel human immunodeficiency virus (HIV) pandemic. In TB endemic countries children carry a very high burden of disease, which may be unrecognised due to the difficulty in making a diagnosis based on clinical, radiological or laboratory methods. One of the main hurdles is the difficulty of obtaining adequate specimens for bacteriological confirmation of disease in children. TB lymphadenitis is the most common extra-pulmonary manifestation of TB, and up to 22% of children with persistent cervical lymphadenopathy and no local cause may have tuberculous adenitis. Fine needle aspiration biopsy (FNAB), a simple and safe out-patient procedure that can be performed by nurses in resource-limited settings, and that provides material for direct microscopy as well as culture and susceptibility testing, provides an excellent opportunity to obtain bacteriological confirmation. However, it remains a greatly underutilised specimen collection modality. This review provides a comprehensive overview of the difficulties faced in the diagnosis of paediatric TB in resource-limited settings, and suggests ways to utilise FNAB as a practical modality for the rapid and effective diagnosis of mycobacterial disease in the significant subset of patients who present with peripheral lymphadenopathy. It also provides detail on how best to perform the technique, and suggests ways of making it more widely available in resource-limited settings, which carry the brunt of the paediatric TB disease burden.