Very informative article on CSF leaks

Cerebrospinal Fluid (CSF) Leaks

This is basically my story...

Spontaneous leaks into the middle ear are usually diagnosed by high-resolution CT scans. This may reveal discrete tegmen defects (mine was 11mm), multiple pinhole fistulae (I had 4), or a combination of these findings. About 6% of the population has some degree of bony defect. Most patients have an ipsilateral conductive or mixed hearing loss, the conductive component caused by CSF in the middle ear. These can be repaired via a middle fossa craniotomy (Leonetti et al, 2005). Surgical repair is used in patients with leaks in the skull.

While CSF leak is generally accompanied by an orthostatic (upright only) headache, this association is not universal and in fact, hearing loss may be more common than headache (this was true for me...I had hearing loss but no headache.)(Oncel et al, 1992).

In theory, a ventilation tube should not be put into an ear with a CSF leak, as this might provide a route for infection to enter the brain. Practically however, the middle ear is not sterile --and it communicates with the nose through the eustachian tube. We also do not know of any study in which infection rates with and without tube were compared -- thus it seems to us that this idea is not only purely theoretical, somewhat illogical, and also unverifiable. My doctors recommended a tube in my ear.

Only 20 cases of leaks due to middle ear infection had been reported as of 2007 (Manjunath, 2007).