Association between preadmission oral antibiotic therapy and cerebrospinal fluid findings and sequelae caused by Haemophilus influenzae type b meningitis

The association between the administration of oral antibiotics and cerebrospinal fluid (CSF) findings and sequelae was investigated in 281 children with Haemophilus influenzae type b meningitis from two prospective studies. Ninety-four (33%) children were pretreated; 59% of pretreated children received ampicillin or amoxicillin. Compared with untreated children, in pretreated children significant decreases were noted in the percentage of polymorphonuclear leukocytes in the CSF (P < 0.03), CSF protein concentrations (P < 0.001) and percentage with a positive CSF Gram stain or culture (P < 0.05). When adjusted for duration of illness prior to admission, only the CSF protein concentrations remained different (P < 0.01). Children who were pretreated were more likely (P < 0.05) to have paresis at one or more follow-up visits and sensorineural hearing loss (P < 0.05), but these differences were diminished when adjusted for duration of illness before admission. The duration of illness prior to admission was significantly (P < 0.0001) longer for pretreated (median, 3.0 days) than for untreated children (median, 1.0 day). The incidence of deafness did not correlate with duration of illness before admission by multiple logistic regression analysis (P = 0.132), but deafness was significantly (P < 0.02; relative risk, 5.9) more common when all children who were ill for more than 1 day prior to admission were compared to those children who were ill for 1 day or less. Oral antibiotics prior to admission (1) do not alter the CSF findings in most patients such that a diagnosis of H. influenzae type b meningitis cannot be established and (2) are associated with an increased likelihood of some neurologic sequelae, in part related to a longer duration of illness noted in pretreated patients before definitive therapy when compared to untreated patients.