The use of blood glucose/cerebrospinal fluid glucose ratio in the diagnosis of central nervous system infection in infants and children.

The diagnosis of bacterial meningitis can be difficult nowadays when antibiotics are freely used in infants and children with fever due to infection, so that a positive smear or culture may be difficult to achieve. In areas where sophisticated methods of diagnosis may be hard to come by, the simple procedure of simultaneously estimating the blood and cerebrospinal fluid (CSF) glucose levels may be helpful in distinguishing bacterial meningitis from viral meningitis. 74 proven cases of bacterial meningitis and aseptic meningitis were investigated prior to treatment. There were 36 cases of bacterial meningitis and 38 cases of aseptic meningitis. The CSF glucose/plasma glucose ratio was calculated for each patient. The cases were divided into two groups; Group A with CSF glucose/plasma glucose ratio of (0.38-2.0) and Group B with CSF glucose/plasma glucose ratio of (0.1-0.35). In Group A, two out of 59 cases died while in Group B, nine out of 15 died (p < 0.01). 44 out of 59 in Group A recovered fully while only two out of 15 in Group B were cured (p < 0.01). It was also found that 54.2% in Group A were admitted in deep coma compared with 86.7% in Group B (p < 0.05) and 25.4% in Group A were admitted with seizures while 66.7% in Group B had convulsion (p < 0.01). Hence, a low CSF glucose/plasma glucose ratio was associated with a poor outcome. The mechanisms responsible for these findings are discussed especially with reference to the blood-brain barrier (BBB).(ABSTRACT TRUNCATED AT 250 WORDS)