CSF rhinorrhoea refers to the drainage of cerebrospinal fluid through the nose. Measures of CSF components such as glucose have been used in the past, but are neither sensitive nor specific; beta-2 transferrin, however, has been shown to have a high positive predictive value. It has also been noted to be characterized by unilateral discharge. It is a sign of a basilar skull fracture. Management includes watchful waiting – leaks often stop spontaneously; if this does not occur then neurosurgical closure is necessary to prevent the spread of infection to the meninges.