Diagnosis and microbiological confirmation of miliary tuberculosis in less than 24 hours

Hintergrund Tuberculosis (TB) remains a major public health issue globally. The TB diagnostics landscape has evolved significantly over the last decade, resulting in easy-to-use molecular assays that can confirm infection with Mycobacterium tuberculosis (MTB) rapidly. We report a case of miliary TB in whom molecular assays established a definitive diagnosis in less than a day, as well as drug susceptibilities.

Methoden Case report

Ergebnisse:Case description A previously healthy 17-year-old boy presented to his local hospital with a history of prolonged cough for 2 months and malaise. There was no history of persistent fevers or night sweats. Over the preceding autumn months, he had experienced several flu-like episodes, which had improved without antibiotics. He had been born in Austria and had only travelled abroad to Italy, Croatia and North Macedonia, all of which have low TB incidence (4.6, 2.7 and 11 per 100,000, respectively). The examination was unremarkable, except for mild tachypnoea and scattered coarse crepitations. His chest x-ray showed multiple millet-sized lesions as well as larger opacities scattered throughout all lung fields. As miliary TB was suspected based on those findings, the boy was transferred to the National Reference Centre for paediatric TB. A tuberculin skin test performed on day 1 of the admission showed an induration of 6 mm after 48 hours. A QuantiFERON-TB Gold Plus assay showed a positive result (interferon-gamma responses: TB1 0.95, TB2 1.14 IU/mL). The result of the first sputum sample analysed with an Xpert MTB/RIF Ultra assay was positive for MTB (no rifampicin resistance detected). An Xpert MTB/XDR assay performed the next day did also not reveal any resistance mutations, and he was therefore started on standard quadruple therapy (HRZE).

Schlussfolgerung This case illustrates two important points. Firstly, TB is often oligosymptomatic in children and adolescents, but should be considered even if a child lives in a low TB prevalence country and has no risk factors for TB, especially as more than half of the children subsequently diagnosed with TB disease have no history of TB contact. Secondly, molecular TB diagnostics can help to dramatically shorten the time frame in which a definitive diagnosis is established, compared with traditional cultures, which take several weeks to produce a result. An expedited diagnosis is particularly important in disseminated TB disease, which is associated with rapid progression and high levels of morbidity and mortality.

Publication History

Article published online:
22 February 2024