Cerebrospinal Fluid Fistula in the Frontal Sinus Secondary to Obstructive Hydrocephalus.

In some rare cases, long-standing hydrocephalus can cause "high-pressure" cerebrospinal fluid fistulas. We report the case of a young overweight woman with rhinorrhea secondary to hydrocephalus with a fistula into the frontal sinus. Brain imaging studies revealed aqueduct stenosis. Ventriculocisternostomy treated the hydrocephalus but did not cure the rhinorrhea, and additional multilayer surgical skull base repair was necessary. In these cases, the CSF leakage acts as a safety valve, and closure will worsen the patient's condition if the causative lesion has not been treated first. Moreover, identifying the exact location of the fistula can be challenging and will usually require high-resolution bone computed tomography.