Abstract
A nation-wide survey on congenital hydrocephalus, including secondary hydrocephalus occurring within one year after birth, was carried out in 1988. The number of patients with congenital hydrocephalus treated during the previous one year was estimated to be 3, 200-3, 500 throughout Japan. The number of new cases of this disease which occurred during the year was calculated to be 800. This indicates a rate of 0.58 per 1, 000 live births. Clinico-epidemiologic features were compared with regard to three subjects listed below.
(1) The difference between the epidemiologic profile of term and preterm infants with hydrocephalus was investigated. As for etiology, the incidences of primary hydrocephalus and hydrocephalus complicated by Arnold-Chiari malformation type IL and meningocele were significantly higher in term infants than in preterm infants. It was estimated that about 30% of the hydrocephalus in preterm infants and only 7.7% in term infants occurred as a consequence of intracranial hemorrhage. The degree of neurological impairment and the mortality rate were higher in preterm infants than term infants.
(2) The changing panorama of infantile hydrocephalus in Japan was investigated comparing the epidemiologic data of four groups according to the birth year. As for pregnancy period, preterm infants with hydrocephalus were gradually increasing recently. Hydrocephalus secondary to intracranial hemorrhage was increasing and that secondary to intracranial infection was decreasing. The rate of shunt malfunction was decreasing significantly.
(3) Clinico-epidemiologic features of intractable hydrocephalus based on the diagnostic criteria of the researchcommittee was investigated comparing intractable with non-intractable groups. The patients in the intractable group were severely handicapped in mental and physical development with CNS malformations, brain damage, or frequent operations. Secondary hydrocephalus showed poorer prognosis than primary hydrocephalus. Among the primary hydrocephalus patients, severe CNS malformations, such as Dandy-Walkercyst, holoprosencephaly, porencephaly and hydranencephaly were the risk factors for poor outcome. In secondary hydrocephalus, intracranial infection and intracranial hemorrhage were risk factors for severe handicaps. The patients operated within 2 months from the birth or within 1 month from the onset showed better outcome. The patients with shunt malfunction or post-operative infection showed inevitably poor prognosis.
