Very little is known about the incidence and etiology of childhood bacterial meningitis in Malaysia. Haemophilus influenzae type b (Hib) is a potentially preventable cause of bacterial meningitis and its incidence has been markedly reduced in North America and Europe as a result of systematic immunization of all children. The proportion of cases of bacterial meningitis caused by Hib in Malaysia, and therefore the potential impact of the vaccine, is not known. To develop a better understanding of this problem, we conducted a surveillance study of postneonatal childhood meningitis in Malaysia.
We conducted a cross-sectional, retrospective review of all cases of postneonatal meningitis diagnosed among patients 12 years of age or less between January 1, 1995, and December 31, 1995 at 5 pediatric departments (Paediatric Institute, Hospital Kuala Lumpur; Kota Bahru Hospital, Kelantan; Hospital Sultanah Aminah, Johor; Hospital Alor Setar, Kedah; and Hospital Kuching, Sarawak) located in 5 of Malaysia's 13 states. Under a standard protocol data were collected concerning signs and symptoms of meningitis; demographic characteristics of the patients (age, gender, racial or ethnic group); duration of hospitalization; radiologic studies; invasive procedures; outcome; and satisfaction of laboratory criteria for bacterial meningitis [either a positive cerebrospinal fluid (CSF) culture for bacteria or 3 of the following 5 findings: CSF white blood cell count of >50/ml with a majority of polymorphonuclear cells; CSF glucose of <1.1 μmol/l or <50% of simultaneous blood sugar; CSF protein of >1 g/l; bacteria seen on direct microscopy of CSF; or bacterial antigen detected by latex agglutination]. At 2 of the 5 study sites (Paediatric Institute Hospital, Kuala Lumpur, and Kota Bahru Hospital, Kelantan), CSF also was sent for viral studies.
During the study period there were 435 cases of clinical meningitis admitted to the 5 centers as follows: Paediatric Institute, 275; Kuching, 67; Alor Setar, 40; Kota Bharu, 38; Johor Bahru, 15. The percentage of all pediatric admissions caused by meningitis ranged from 0.5% in Johor Bahru to 2.1% in Kuching, with a mean of 1.2%. The age distribution of meningitis cases was; <5 years, 91.5%; <1 year, 76%; <6 months, 54%; <3 months, 29.5%; and 4 to 6 weeks, 11%.
Of the 435 cases only 71 (16.3%) fulfilled the laboratory diagnostic criteria. No lumbar puncture was performed in the other children, reflecting the widespread belief in the local population that lumbar puncture will lead to later paralysis or impotence. Subsequent analysis is limited to these 71 patients. There were 41 boys and 30 girls; 47 were Malays, 8 Sarawakian natives, 5 West Malaysian aborigines, 9 Chinese and 2 Indians.
Of the 71 confirmed cases of meningitis an organism was isolated in 58 cases: Hib, 28; Streptococcus pneumoniae, 8; Salmonella spp., 7; Staphylococcus aureus, 4; Escherichia coli, 3; Neisseria meningitidis, 2; Mycobacterium tuberculosis, 1; group B Streptococcus, 2; Yersinia spp., 1; herpes simplex, 1. Hence, one-half of all bacteriologically proved cases were caused by Hib.
The 71 patients spent an average of 19.5 days in hospital. Thirty-five (49%) had computerized tomographic scans; 46 (65.8%) had ultrasound examinations; 13 (18.3%) had subdural effusions of which 7 were drained; 8 developed hydrocephalus and 4 of these were shunted. Nine (12.5%) children died, 39 (55%) were discharged well, 21 (29%) developed neurologic deficits and 2 were lost to follow-up. Of the 21 with neurologic sequelae all had motor deficits and 6 had quadriplegia. Four (5.6%) developed cortical blindness and 3 developed epilepsy [36 (51%) had seizures during the acute illness]. Data on hearing loss were incomplete.
The glaring weakness of this study is the small number of cases (71, 16.3%) that fulfilled laboratory diagnostic criteria. However, given the fact that most of the meningitis cases affect segments of the population that traditionally are apprehensive of lumbar punctures, this situation is unlikely to improve in studies done in the near future. Nonetheless the finding in this study that one-half of all cases of proven meningitis were caused by Hib is consistent with previous retrospective studies done in Malaysia.1-3 Thus it probably is justified to assume that 50% of all childhood bacterial meningitis in Malaysia is caused by Hib.
As in the previous studies the majority of cases (76%) were in infants <1 year of age, who bear the brunt of morbidity and mortality. However, because of the small number of confirmed cases, it is not possible to extrapolate these data to estimate the total number of childhood Hib meningitis cases in Malaysia based on pediatric admissions. Hence the true incidence of Hib meningitis in Malaysia remains unknown.
1. Yeat EC. Hearing loss in childhood meningitis. Dissertation for Master's Degree in Otorhinolaryngology, National University of Malaysia, 1993.
2. Choo KE, Ariffin WA, Ahmad T, Lim WL, Gururaj AK. Pyogenic meningitis in hospitalised children in Kelantan, Malaysia. Ann Trop Paediatr 1991;10:89-98.
3. Tee AC. Childhood meningitis at University Hospital, Kuala Lumpur, 1980-89. Dissertation for Master's Degree in Medicine (Paediatrics), University of Malaysia, 1993.
FIRST INTERNATIONAL CONFERENCE ON HAEMOPHILUS INFLUENZAE TYPE b INFECTION IN ASIA
The Editors thank the Association pur l'Aide à la Médicine Préventive, the Foundation Mérieux, and the World Health Organization for supporting publication of these proceedsings, and Jennifer Wells for her editorial assistance.