Severity and frequency of sequelae of bacterial meningitis in Alaska Native infants. Correlation with a scoring system for severity of sequelae.

Abstract

To (1) determine the frequency and severity of sequelae of Haemophilus influenzae type b and Streptococcus pneumoniae meningitis in Alaska Native children, (2) compare morbidity and mortality of H influenzae b and S pneumoniae meningitis, and (3) evaluate the applicability of the Herson-Todd prognostic score (HTPS) to both H influenzae b and S pneumoniae meningitis in this population. A retrospective study of all cases of H influenzae b and S pneumoniae meningitis in Alaska Native children younger than age 5 years. Data on meningitis sequelae, obtained from medical charts and records of the Infant Learning Program, were collected, and incidence of sequelae tabulated. Data obtained on admission to the hospital were used to calculate HTPS. Indian Health Service facility for the Yukon-Kuskokwin Delta region of southwest Alaska. 51 of 63 Alaska Native children with H influenzae b meningitis and 13 of the same 63 Alaska Native children with S pneumoniae meningitis occurring between 1980 and 1988. One child was infected with both organisms, producing a total of 64 cases for study. Cases were identified by surveillance for these diseases between January 1, 1980, and December 31, 1988, maintained by the Arctic Investigations Program, Centers for Disease Control. Sequelae of bacterial meningitis caused by H influenzae b were equal to or exceeded rates of sequelae described in other children in the United States. After H influenzae b meningitis, motor abnormalities (29%) and hydrocephalus (7%) occurred two to four times more often in Alaska Native children than in children in other parts of the United States. Differences in severity of H influenzae b sequelae could not be accounted for by microbiologic markers of the H influenzae b strain, including ampicillin sensitivity, biotype, outer membrane protein type, or electropherotype. Numbers of cases of S pneumoniae meningitis were too small for statistically valid comparison, but sequelae of S pneumoniae meningitis occurred in roughly equal proportion as sequelae of H influenzae b meningitis. The HTPS was applied to Alaska Native children with H influenzae b meningitis and was found to be very accurate in predicting children with major sequelae. Analysis of the prognostic factors used in deriving the HTPS revealed a unique set of predictors for sequelae in Alaska Native children: seizures at admission, glucose levels in cerebrospinal fluid of less than 1.1 mmol/L; and male gender, with a significant predictive interaction between male gender and age less than 6 months at admission. Alaska Native children suffer greater neurologic morbidity as a result of H influenzae b meningitis than do their non-Native counterparts. The HTPS was a good predictor of major sequelae in Alaska Native children with H influenzae b or S pneumoniae meningitis and could be useful in determining which patients need referral to a tertiary care center.