Spontaneous Septum Pellucidum Fenestration Complicating Posthemorrhagic Hydrocephalus in an Extremely Low Birth Weight Infant

A 25 weeks' gestation infant developed posthemorrhagic hydrocephalus. On postnatal Day 29 an ultrasound of the brain showed a fenestration between the septum pellucidum and the left lateral ventricle which continued to enlarge as the clinical course deteriorated. Color Doppler showed low flow between the septum pellucidum leaflets suggesting a persistence of erythrocytes. However, color Doppler artifacts could have resulted in this interpretation. The infant died on day 34 from multiple organ failure. Despite spontaneous fenestration of the septum pellucidum being previously described, it has not been associated with hemorrhagic hydrocephalus. Serial scanning of intracranial structures by high frequency probes can allow better understanding of the pathophysiology of neurologic complications in preterm infants.