Infantile hydrocephalus and the slit ventricle syndrome in early infancy.

Slit ventricle syndrome is well known as a complication in the treatment of hydrocephalus by shunting. It is generally considered to be a chronic (but not acute) complication, occurring years after the shunt procedure; there has been no report of this syndrome occurring before 1 year of age. The authors present infantile cases that developed a severe form of this syndrome shortly after shunt procedures and discuss the pathophysiology in comparison to experience with older cases. The causative factor was thought to be extremely low intracranial pressure with resultant microcephalus created by double or multiple shunt placement. The condition resulted in rapid onset of coma and respiratory arrest, which was successfully treated by subtemporal decompression or placement of an antisiphon device, with insertion of a higher pressure valve. The specific characteristics of infantile hydrocephalus are analyzed in the light of this complication from a series of 58 treated infants. In a follow-up of over 1 year in 42 cases, analysis revealed that slit ventricle occurs most frequently in immature young infants shunted before 1 month of age (85.7% or 18/21 cases). In contrast, subdural hematoma after shunting is an extremely rare phenomenon in premature or mature neonates. Slit ventricles were thought to result from high intracranial compliance due to the softer brain and more markedly widened cranial sutures of infantile hydrocephalus in the younger age group. The functioning period of the initial shunt was also much shorter in younger infants, and this may be because the ventricular shrinkage to a slit can cause shunt malfunction with or without developing the slit ventricle syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)