[Management of cerebrospinal fluid fistulae: physiopathology, imaging and treatment].

Cerebrospinal fluid (CSF) fistulae can produce leakage through a defect in the bony skull and meninges into the contiguous air-filled cavities at the base of the skull. The major risk is central nervous system infection. When abundant clear rhinorrhea or otorrhea is present, the diagnosis is obvious and imaging is used to localize the fistula. Computed tomography (CT) with millimetric slices and magnetic resonance imaging (MRI) are the most effective diagnostic tools. CT cisternography, an invasive procedure, should only be used when the diagnosis remains uncertain following CT scan and MRI. When CSF leakage is sparse or intermittent, the diagnosis can be made by measuring beta-2 transferrine in the escaping fluid. CT scan followed by MRI are also useful for making the diagnosis and locating the fistula when exterior leakage is absent. CT scan alone is effective for assessing isolated otorrhea. If the diagnosis remains uncertain after all these studies have been used, the patient should be closely followed clinically and isotopic study or surgery should be considered.