Insights into the epidemiology of infant hydrocephalus.

INTRODUCTION: Infant hydrocephalus represents an important public health issue. Recent analysis of registry-based data has improved our understanding of the variable epidemiology of infant hydrocephalus around the world and the consequent burden of disease that this vulnerable population must carry throughout their lifetimes. The purpose of this article is to review the epidemiology of infant hydrocephalus, highlighting the ways in which analysis of prospectively collected registry data has contributed to our current knowledge and how similar methods may lead to new discovery. DISCUSSION: Congenital abnormalities and spina bifida-associated hydrocephalus, along with acquired postnatal hydrocephalus secondary to intraventricular hemorrhage of prematurity and infection, represent the most common etiologies of infant hydrocephalus, with their relative prevalence dependent on geographic region and socioeconomic status. Best current estimates suggest that the incidence of congenital and acquired infant hydrocephalus may be between 80 and 125 cases/100,000 births depending on world region. These incidence figures and their forecasts, together with improved survival associated with promptly diagnosed and treated hydrocephalus, suggest that the burden of hydrocephalus, as measured by prevalence, is primed to increase. Counterbalancing these statistics is evidence that perhaps, in some regions, improvements in neurosurgical and general perinatal care, as well as shifting indications for initial surgical intervention in these infants (and therefore in the very definition of hydrocephalus itself), the number of infants who require first time surgical treatment for hydrocephalus, may be decreasing. Further longitudinal data collection will undoubtedly assist in determining whether these trends are robust.
CONCLUSION: When one takes a global perspective, complexities related to the underlying epidemiology of infant hydrocephalus become abundantly clear. The causes of infant hydrocephalus vary from one world region to another, largely related to the underlying income characteristics of the population. Likewise, increased birth rates in low-income areas of the world are likely to result in an increased incidence and prevalence of infant hydrocephalus in those regions, whereas sophisticated and resource-intensive advancements in perinatal care available in other regions may result in decreased epidemiological estimates of disease burden in others. Further analysis of high-quality registry-based data may help clarify these issues.