EPIDEMIOLOGY OF CONGENITAL HYDROCEPHALUS IN UTAH, 1940-1979 - REPORT OF AN IATROGENICALLY RELATED EPIDEMIC

As part of an epidemiological study of congenital hydrocephalus in Uta h, we focused on the effect of ascertainment sources and temporal vari ability to further delineate the causes of this relatively common, han dicapping birth defect. The incidence and distribution of 934 reported cases diagnosed prior to age 6 months, and born to Utah residents fro m 1940 to 1979, were analyzed. Data were ascertained by examination of multiple sources, e.g., 982,066 birth, 11,161 fetal death, and 248,20 8 death certificates, and selected hospital and clinic records. Of the 934 reported cases, 700 met our selection criteria for congenital hyd rocephalus, which results in a crude incidence of 0.70 per 1,000 live and stillbirths. Seventy-one cases (10.1) had additional, multiple con genital anomalies. The male/female sex ratios of the 619 cases of isol ated congenital hydrocephalus (occurring as a single entity or in the absence and those with multiple congenital anomalies (71 cases) were v irtually identical, being 1.45 and 1.48, respectively. A significant 8 5% increase in the rate of reported cases was observed for the period 1966 to 1970. However, examination of patients' records from 1966 to 1 975 in the hospital responsible for almost all of this increase sugges ts that this was iatrogenically related ''epidemic'' caused by several factors: the introduction and possible misinterpretation of pneumoenc ephalograms (PEG) in the diagnosis of hydrocephalus (PEG was replaced by CAT scanning in the early 1970s), inappropriate diagnosis, and inco rrect recording of age at time of diagnosis. (C) Wiley-Liss, Inc.