Unilateral posthaemorrhagic hydrocephalus in the neonatal period or later in infancy

Five infants who developed unilateral hydrocephalus associated with antenat al or perinatal intraventricular haemorrhage (IVH) in the neonatal period o r later in infancy are reported. Unilateral hydrocephalus occurred followin g discharge home in four of our five cases, two of whom had been treated du ring the neonatal period with either serial lumbar punctures or punctures f rom a Rickham reservoir. An obstruction at the level of the foramen of Monr o following a large subependymal matrix bleed appeared to be the underlying aetiology. These data suggest that infants who suffer a predominantly unil ateral IVH, with or without parenchymal involvement, can subsequently devel op unilateral hydrocephalus. Cranial ultrasound examinations should be repe ated at regular intervals during the first year of life, as unilateral hydr ocephalus can still develop after a period of apparent stabilization.