Intrathecal streptomycin and cerebrospinal glucose estimation.

The determination of cerebrospinal fluid glucose is important in the diagnosis and prognosis of tuberculous meningitis. The restoration to normal of the characteristically low glucose values is considered to reflect the success of streptomycin therapy. Intrathecal injection of the antibiotic is usually employed in tuberculous meningitis, and attention has been drawn to the fact that streptomycin itself has reducing properties (Cruickshank, 1951) and may interfere with the accurate measurement of cerebrospinal fluid glucose. Alvaro and Nicola (1948), using the HagedornJensen method, reported that various streptomycin preparations were strongly reducing, and that 1 mg. of anhydrous streptomycin base was equivalent to values up to 4.5 mg. of glucose. It was stated by Wilson (1951) that the intrathecal injection of antibiotics may give temporary false sugar values, so that estimations carried out during and for an indeterminate time after this form of treatment are invalidated. These considerations suggested an investigation of the reducing powers of streptomycin and dihydrostreptomycin with special reference to the method of measuring cerebrospinal fluid glucose (Nelson, 1944) used in this laboratory. In addition, cerebrospinal fluid glucose results from a number of cases of tuberculous meningitis treated with intrathecal streptomycin were examined for any evidence of falsely high values.