Miliary TB – a retrospective cohort study of diagnostic and clinical features

BACKGROUNDTB remains a major global health challenge causing significant morbidity and mortality. Miliary TB, a severe form of the disease, remains poorly characterised in large cohorts, and often has poor outcomes, especially in high-prevalence resource-poor settings.METHODSThis retrospective cohort study characterises diagnostic and clinical features of miliary TB in 84 confirmed cases over 9 years (2014-2022) across East London, UK. Demographic, clinical, microbiological, biochemical, and imaging data were collected retrospectively from electronic health records of all consecutive patients diagnosed with miliary TB at a large hospital trust.RESULTSThe central nervous system (CNS) was the most common site of extra-pulmonary spread after intra- and extra-thoracic lymph nodes. Neurological symptoms were unreliable indicators of CNS involvement, supporting routine magnetic resonance imaging (MRI) brain for all miliary TB patients regardless of symptoms, given its superior sensitivity over lumbar puncture and computed tomography (CT) brain. Admission hyponatraemia, thrombocytopaenia, and lymphopaenia all predicted increased duration of hospital stay, supporting their use as biomarkers of disease severity.CONCLUSIONRoutine MRI brain should be considered for all miliary TB patients, and admission hyponatraemia robustly predicts increased disease severity. These findings help inform clinical decision making and guidelines for the management of miliary TB..