CSF otorrhea is defined as leakage of cerebrospinal fluid (CSF) from the subarachnoid space into the middle ear cavity or mastoid air cells and then out the ear via a perforation in the tympanic membrane or defect in the external ear.
On this page:
Epidemiology
There are a number of underlying causes, and thus no specific demographic is affected.
Clinical presentation
Patients typically present with conductive deafness and a watery discharge from the ear (requiring a defect in the tympanic membrane).
The diagnosis can be confirmed by identifying beta-2 transferrin in the fluid.
Pathology
Etiology
- congenital
- labyrinthine malformation (e.g., cochlear incomplete partition with stapes footplate deformity)
- bony and dural defects along the temporal bone surface (especially tegmen)
- enlargement/abnormal development of bony canals
- aberrantly distributed arachnoid granulations
- traumatic/iatrogenic
- most often due to transverse fractures of the temporal bone
- otologic surgery
- infection
- neoplastic
Radiographic features
CT cisternography
Findings on CT cisternography include:
- soft tissue mass with adjacent bony defect
- leakage of contrast into middle ear cavity
- bony defects
- labyrinthine malformations
- fistulous tracts
- enlarged labyrinthine facial nerve canal
MRI
Findings include:
- CSF signal intensity in the bony defects
- CSF signal intensity in middle ear cavity
- associated empty sella
- dural enhancement after gadolinium administration
Nuclear medicine
Radionuclide cisternography
In complex cases, nuclear cisternography may be performed.
See also
- CSF rhinorrhea, which can sometimes be due to leak of CSF into the middle ear, through the Eustachian tube, and out the nose