Pseudo-cerebrospinal fluid rhinorrhea after skull base surgery

Pseudo-Cerebrospinal Fluid Leaks of the Anterior Skull Base: Algorithm for Diagnosis and Management

Objective  Pseudo-cerebrospinal fluid (CSF) leaks are a rare cause of unilateral, watery rhinorrhea. We proposed a step-wise approach to evaluate these cases. Design  It involves a single-center retrospective cohort study. Setting  The setting is that of a tertiary academic medical center. Participants  Ten patients with diagnosis of pseudo-CSF leak over a 21-year period were evaluated using our proposed algorithm that includes computed tomography, magnetic resonance imaging, nasal endoscopy, β-2 transferrin, intrathecal fluorescein, and surgical exploration of the anterior cranial base. Main Outcome Measures  The occurrence of intracranial infection and resolution of the symptoms were evaluated at a mean follow-up of 94.4 months. Results  Eight patients had history of skull base fracture or surgery. In all patients computed tomography, magnetic resonance imaging, and nasal endoscopy did not show signs of CSF leak. Beta-2 transferrin testing was performed in five patients, being negative in all of them. Intrathecal fluorescein was performed in seven patients, being negative in five and inconclusive in two. Surgical exploration was performed in five patients, definitively ruling out CSF leak. Six patients were treated with intranasal ipratropium, resolving the symptoms in all cases. Conclusion  The presented algorithm provides a step-wise approach for patients with unilateral watery rhinorrhea, allowing to safely ruling out CSF leak.

Pseudo-Cerebrospinal Fluid Rhinorrhea Resulting from Aberrant Cross-Innervation of Trigeminal and Facial Nerves following Skull Base Surgery

Objectives Pseudo-cerebrospinal fluid (CSF) rhinorrhea is a rare phenomenon, presumed to result from aberrant autonomic reinnervation of the paranasal mucosa following injury to the greater superficial petrosal nerve or periarterial plexus. In this report, we discuss the case of a postoperative patient with pseudo-CSF rhinorrhea exacerbated by chewing and propose a novel mechanism of pseudo-CSF rhinorrhea.

Case Report A 46-year-old man was found to have mastication-induced unilateral clear rhinorrhea following transtemporal resection of a cerebellopontine angle tumor. Computed tomography cisternogram and β-2 transferrin analysis proved negative for any evidence of CSF leak.

Conclusions Pseudo-CSF rhinorrhea exacerbated by mastication has not been previously reported in the literature. We propose aberrant cross-innervation of the trigeminal and facial nerves as the mechanism underlying the patient's condition. Pseudo-CSF rhinorrhea is an important entity to identify following skull base surgery because it may spare patients from the unnecessary invasive procedures and morbidity associated with the management of a presumed CSF leak.