Cerebrospinal fluid dynamics and rhinorrhea: the role of shunting in repair.

CSF rhinorrhea can have many causes: traumatic, neoplastic, and iatrogenic origins are common. Most traumatic rhinorrhea ceases after a trial of conservative management. While obvious erosion or traumatic destruction of vital structures may be the underlying cause, other pathophysiologic mechanisms may be working in the formation of CSF rhinorrhea, which may require the combined skills of the otolaryngologist and the neurosurgeon. Leakage of CSF is seen in "high-pressure rhinorrhea," a pathophysiologic state wherein the underlying problem is poor CSF resorption. The result is increased intracranial pressure and eventual rhinorrhea or otorrhea. Areas of CSF leakage correspond to sites of congenital weakness in the cribriform plate region, the parasellar region, or the temporal bone. Weak areas in old base-of-skull fracture sites may leak with increased intracranial pressure. The initial management should stress correction of the deranged pathophysiology, namely shunting. Surgical repair is secondary to controlling the abnormal CSF dynamics.