Cerebrospinal fluid glucose and leukocyte responses in experimental meningitis

Abstract

The fall in cerebrospinal fluid (CSF) glucose and CSF leukocyte response was studied in cats with experimental meningitis. Klebsiella pneumoniae or Streptococcus pneumoniae were injected intracisternally, and the latter organisms were incubated with CSF in vitro. When 10 6–10 9 K. pneumoniae were incubated with 4 ml of CSF, the time necessary for the glucose to decrease to less than 10 mg/dl ranged from 6.5 to 2.5 h, at a rate proportional to the size of the inoculum. When the same numbers of bacteria were injected intracisternally, the time ranged from 9 to 3 h, and the CSF leukocyte response did not exceed 1200 WBC/mm 3. At this time, only minimal histological changes in brain and choroid plexus were seen. Twenty hours after intrathecal K. pneumoniae, large numbers of leukocytes (up to 4 × 10 4/mm 3) were recovered from the CSF. Regardless of the number of leukocytes, however, hypoglycorrhachia occurred when the CSF contained more than 10 7 bacteria/ml. At this interval, large numbers of leukocytes were seen invading the stroma of the choroid plexus, leptomeninges and perivascular spaces. When 10 8 S. pneumoniae were injected intracisternally, CSF glucose concentration decreased as rapidly as with K. pneumoniae. The spinal fluid leukocyte response to S. pneumoniae was, however, greater than that to K. pneumoniae. These results suggest that under the conditions of these studies, hypoglycorrhachia of bacterial meningitis is the result of metabolism of the bacteria with little contribution from the leukocytes.