Diagnosis and Management of Spontaneous Massive Pneumocephalus Without CSF Leak

Objective: Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a syndrome of increased intracranial pressure without underlying mass lesion. They are often associated to spontaneous CSF leaks through the skull base However, to our knowledge, there is no described reports of IIH patient who present with spontaneous pneumocephalus without CSF leak. Here we describe two patients with IIH that presented to our hospital with spontaneous pneumocephalus, elevated ICP, and were found to have middle fossa defects.

Methods: We describe our experience with two patients who presented with headaches and underwent head imaging that revealed massive spontaneous pneumocephalus. The first patient is a 50 year-old female (BMI 29) with known history of IIH who previously presented with spontaneous pneumocephalus that was managed conservatively and resolved. She represented with sudden onset headache and right ear pain. Imaging revealed recurrence of right temporal pneumocephalus with extension into the right lateral ventricle. The second patient was a 68 year-old female (BMI 29) without prior history of IIH who similarly presented with sudden onset headache and left temporal pneumocephalus including air extension into the left lateral ventricle. Both patients did not have CSF leakage. Both patients remember pushing air into the ears closing the nose and mouth to “compensate” for ear pressure.

Results: Both patients underwent extensive medical workup including skull base imaging. The second patient underwent nuclear cysternography and no CSF leakage was identified. Skull base imaging revealed tegmen defects in the right and left temporal bone in each patient respectively. Both patients subsequently underwent middle fossa exploration on the right and left side respectively. The side chosen for surgery was based on the presence of air in the temporal lobe. In the first patient, an encephalocele was found with an associated dural defect and temporal bone defect. In the second patient, we found an encephalocele along with multiple dural defects overlying bone defects. In both patients the skull defects were repaired using bone wax. The dural defects were repaired both primarily as able and with Duragen followed by Alloderm. The second patient subsequently underwent an LP that showed an opening pressure of 36 and underwent placement of ventriculoperitoneal shunt. Both patients repeat head CT showed improvement in their pneumocephalus after surgery.

Conclusion: Patients with IIH can present with spontaneous pneumocephalus without CSF leak. We propose that the encephalocele works as a one-way valve allowing air in and no CSF out in the presence of external pressure. These patients should be instructed to avoid forcing air into the ears. The presence of spontaneous pneumocephalus in a patient should raise concern for IIH. The patients should undergo explorative surgery to identify and repair the defect if medical workup is not revealing.