Spontaneous pneumocephalus in the posterior fossa in a patient with a ventriculoperitoneal shunt: case report.

Abstract

A unique case of spontaneous pneumocephalus is described. It appeared a few years after the uneventful introduction of a cerebrospinal fluid shunt and was probably attributable to a defect of the posterior mastoid plate. A 65-year-old man presented with a subacute onset of vertigo, vomiting, and atactic gait instability. The patient had undergone a ventriculoperitoneal shunt implantation 2 years previously for communicating hydrocephalus. A computed tomographic scan revealed a posterior fossa pneumatocele without hydrocephalus. A simple mastoidectomy was performed. Detection of the area of the bone defect was followed by mastoid obliteration with abdominal fat. Clinicians should be aware that pneumocephalus can occur spontaneously, with or without obvious shunt problems. Treatment should be directed toward the area through which air penetrated the posterior fossa.