CSF carnitine is a potential biomarker in paediatric tuberculous meningitis

The poor outcome of tuberculous meningitis (TBM) is largely due to the difficulty of diagnosis caused by nonspecific symptoms and the absence of specific and sensitive tests. Carnitines regulate energy metabolism, and their elevation has been consistently reported in the cerebrospinal fluid (CSF) of TBM patients. We employed a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach to investigate the acylcarnitine metabolome in paediatric TBM, comparing it to non-meningitis controls (NMC) and viral meningitis (VM). We also investigated correlations of significant acylcarnitines with clinical metadata. We found that short-chain acylcarnitines were significantly elevated in TBM. Acetylcarnitine, propionylcarnitine, and butyrylcarnitine demonstrated significant diagnostic potential in distinguishing between TBM and control groups, with 80-90% specificity and 70-80% sensitivity. Free carnitine stood out as the strongest potential marker for TBM, distinguishing TBM from NMC (100% specificity, 90% sensitivity) and VM (80% specificity, 90% sensitivity). Furthermore, free carnitine is strongly correlated with basal meningeal enhancement and hydrocephalus, key neuroradiological markers of TBM. Free carnitine could serve as a potential biomarker for TBM, as well as a marker of TBM severity. Our results suggest that disruptions in fatty acid and energy metabolism in TBM cases are important because free carnitine plays a crucial role in the β-oxidation of fatty acids by transporting long-chain fatty acids into the mitochondria for energy production.