[Spontaneous cerebrospinal rhinorrhea. Etiology--differential diagnosis--therapy]

CSF rhinorrhea is called spontaneous if it is due neither to a trauma, nor an intracranial tumour or a congenital malformation. Spontaneous CSF rhinorrhea is extremely rare: the fistula is usually found in the roof of the ethmoid sinus, less often in the walls of the sphenoid sinus. There is a striking prevalence of female patients. We describe a female patient who showed spontaneous CSF rhinorrhea from a leak in the anterior roof of the sphenoid sinus. The possible aetiology, diagnostic measures and therapy are discussed. Areas of reduced resistance in the anterior skull base may be congenital, or may be acquired due to later focal atrophy. The diagnosis of CSF rhinorrhea can be established by the glucose test, isotope scanning, immunoelectrophoresis and fluorescence endoscopy. The most reliable methods of distinguishing between a traumatic or neoplastic lesion and a spontaneous CSF rhinorrhea are high-resolution computed tomography (CT) and magnetic resonance tomography. High-resolution CT is also the best method for localization of the bony defect. Elevated intracranial pressure must be ruled out carefully. The treatment of choice is closure of the fistula, preferably by the nasal surgeon, using either the endonasal-transseptal, the endonasal-transethmoidal or the paranasal-transethmoidal approach in order to preserve olfaction and to avoid the risk of a frontal lobe lesion which is a complication of the neurosurgical approach. Interposition of a fascial or dural graft is considered to be an important technical detail for achieving a secure closure of the fistula; packing can be avoided by additional sealing of the patch with fibrinogen glue.