Spontaneous pneumocephalus in a newborn infant with myelomeningocele and hydromyelia.

The authors report a preterm boy, born at 35 weeks gestation with hydrocephalus and an open sacral myelomeningocele. Cranial ultrasound showed ventricular dilatation with posture-dependent intraventricular bright echoes, representing air. Ultrasound of the cervical spine and the craniocervical junction revealed marked hydromyelia of the whole spinal cord, as well as a Chiari II malformation. Air penetrating the enlarged central canal through the neural tube defect and subsequently ascending to the cranial cavity was demonstrated by fluoroscopy. After a review of the literature, the authors conclude that the association of spontaneous pneumocephalus with myelomeningocele could indicate severe hydromyelia. These malformations are readily demonstrated by ultrasound in newborn infants.