Tension pneumoventricle in a patient with a ventriculoperitoneal shunt and an ethmoidal meningoencephalocele.

Background: Tension pneumoventricle is a rare, life-threatening complication. It has been rarely described in patients with ventriculoperitoneal (VP) shunts. Case Description: A 28-year-old male patient with a VP shunt became progressively lethargic after falling from his wheelchair. Skull X-rays and head CT scan showed abundant air inside the ventricles. He was taken to the operating room, and the shunt was revised without improvement. Two days later, a frontal external ventricular drain was placed to remove the air. In the investigation toward the etiology of the pneumoventricle, a review of previous head CT scans and brain MRIs showed that the patient had a small left frontonasal meningoencephalocele extending into the ethmoid, which had been unnoticed. He underwent repair of the defect with adequate sealing of the frontal skull base. Conclusion: In a shunted patient with moderate or severe symptoms from a tension pneumoventricle, external ventricular drainage is required to remove the air as the shunt is inadequate.