Biochemical markers in tuberculosis meningitis

In the search for finding biochemical markers in patients with tuberculosis meningitis (TBM), amino acids, nitrite (metabolite of nitric oxide), vitamin B12, homocysteine along with catecholeamines and their metabolites are quantitated in cerebrospinal fluid. Among the amino acids, aspartic acid (ASP) and glutamic acid (GLU) both excitatory amino acid, GABA, glycine (GLY),phenylalanine (PHE),tryptophan (TRP) were all significantly increased where as taurine (TAU) is significantly decreased in TBM patients. The levels of nitrite and its precursor arginine (ARG) were significantly higher in TBM patients and are linearly related. There is also a positive correlation between GLU and ARG and nitrite indicating that GLU, ARG and nitrite are interrelated and contribute simultaneously to the neuronal death in TBM. Among the catecholamines, noradrenaline (NA) and its metabolite 3-methoxy 4-hydroxyphenylglycol (MHPG) are significantly increased where as unchanged levels of dopamine (DA) and its metabolite homovalinic acid (HVA), and increased level of 3,4-dihydroxy phenylacetic acid (DOPAC) were observed. Among the indoleamines, 5-hydroxy 3-indoleacetic acid (5-HIAA) is unchanged where as serotonin (5-HT) level is significantly increased. A significant increased level of CSF homocysteine (HC) and a decreased level of vitamin B12 was found in TBM patients. This indicates that TBM patients are particularly prone to vitamin B12 deficiency resulting into increase level of HC. This study shows the importance of these biological markers which could be used in designing the therapy and confirming the diagnosis of these patients.