Epidemiology of infantile hydrocephalus in Sweden. III. Origin in preterm infants.

The aetiology of infantile hydrocephalus (IH) was studied in a population-based series of 61 children with IH born 1967-82 at less than 37 weeks of gestation. A prenatal origin was present in 17 children (28%), a pre- and perinatal in 17 (28%), a perinatal in 26 (43%) and a postnatal in one (1%). The predominant single cause was postaemorrhagic IH, which was diagnosed in 19 (31%). In addition, an undiagnosed cerebral haemorrhage was considered to be the cause in another 25%. The outcome differed between pathogenetic groups. Children with a clear onset of IH (pre-, peri- or postnatal) were found to be at high risk for early death or multiple impairments. Sixteen of 39 (41%) within these groups had died before 2 years of age and 18 of the 23 (78%) survivors showed major neurological dysfunction. This contrasted to no mortality and 41% major dysfunction in children with a less clear onset of IH. A new subgroup consisting of infants born before 28 weeks of gestation emerged in the early 1980s. All infants with IH in this group developed a severe multihandicap condition.