Unilateral posthaemorrhagic hydrocephalus in the neonatal period or later in infancy.

Five infants who developed unilateral hydrocephalus associated with antenatal or perinatal intraventricular haemorrhage (IVH) in the neonatal period or later in infancy are reported. Unilateral hydrocephalus occurred following discharge home in four of our five cases, two of whom had been treated during the neonatal period with either serial lumbar punctures or punctures from a Rickham reservoir. An obstruction at the level of the foramen of Monro following a large subependymal matrix bleed appeared to be the underlying aetiology. These data suggest that infants who suffer a predominantly unilateral IVH, with or without parenchymal involvement, can subsequently develop unilateral hydrocephalus. Cranial ultrasound examinations should be repeated at regular intervals during the first year of life, as unilateral hydrocephalus can still develop after a period of apparent stabilization.