(A812) Diagnostic dilemma: cerebrospinal fluid leak from spontaneous intracranial hypotension with concurrent skull base pathology

Introduction: Spontaneous intracranial hypotension (SIH) is a condition characterized by low cerebrospinal fluid (CSF) pressure often due to non-iatrogenic CSF leakage at the level of the spine. The most common presenting symptom is a postural headache, which is also commonly seen in skull base CSF leaks. SIH is an underrecognized entity, but an important consideration on the differential when patients present with symptoms suggestive of low CSF pressure.

Methods: A 72-year-old male with a history of known right petroclival meningioma presented with new onset positional headache while undergoing proton irradiation for treatment. He denied any otorrhea, rhinorrhea, or salty or metallic taste. Imaging showed a large, stable meningioma with an infiltrating component extending into the right middle ear with associated stable tympanomastoid effusion, as well as new diffuse pachymeningeal thickening and bilateral subdural hygromas. Due to concern for skull base CSF leak related to the tumor, diagnostic myringotomy was performed but fluid was negative for beta 2 transferrin. MRI cervical, thoracic, and lumbar spine did not show any dural ectasia or discrete source of possible leak. CT cisternogram showed no evidence of cranial or spinal CSF leak on initial or delayed scans. Nuclear medicine radionucleotide cisternogram was then performed and demonstrated findings consistent with CSF leak at the level of the upper thoracic spine.

Results: Patient underwent epidural blood patch with clinical improvement of postural headaches within 1 day.

Conclusions: Postural headaches in patients with skull base pathologies raise concern for cranial CSF leak for all otolaryngologists; however, after a cranial etiology is ruled out, a spinal source due to SIH is important to consider.