Magnetic resonance imaging of miliary tuberculosis of the central nervous system in children with tuberculous meningitis

Background Tuberculous meningitis (TBM) is closely associated with miliary tuberculosis and a pathogenetic relationship is suspected, although it has been proposed that the two processes are unrelated. Objective To describe miliary tuberculosis of the central nervous system (CNS) on MRI in children with TBM. Materials and methods A retrospective descriptive study of 32 paediatric TBM patients referred for MRI. The presence of miliary nodules in the CNS was recorded. Lesions were categorized according to their distribution, enhancement pattern, size and signal characteristics. Results A miliary distribution of nodules was present in 88% of patients. All patients with a miliary distribution had leptomeningeal nodules and 18% of these patients had deep parenchymal nodules in addition. At least one tuberculoma with central T2 hypointensity was identified in 39% of patients. Conclusion The high prevalence of miliary leptomeningeal nodules in the CNS of children with TBM is significant because it points to a pathogenetic relationship that has long been suspected on epidemiological grounds. Our findings challenge the concept that miliary tuberculosis is only an incidental finding in TBM patients and suggest that it plays an integral part in the pathogenesis.