A perilymph fistula is an abnormal opening between the air-filled middle ear and the fluid-filled inner ear. In most cases, there is a tear or some type of defect in the oval window or round window membranes. In rare cases, superior semi-circular canal dehiscence syndrome causes an abnormal opening is in the bone of the ear (the otic capsule). Perilymphatic fistula can also rarely occur as a late complication of mastoid, cholesteatoma surgery. In these cases, the fistula is caused by repeated infections in the opened mastoid.
Some perilymphatic fistulas are congenital, that is, present from birth. Other common causes of perilymphatic fistula include head trauma, acoustic trauma, or barotrauma.
The symptoms of perilymphatic fistula vary in severity and complexity and can range from very mild to completely incapacitating. When a fistula is present, changes in barometric pressure such as when flying or diving, will directly affect the inner ear stimulating the hearing and balance structures. These symptoms include dizziness, vertigo, balance problems, nausea and vomiting. Tinnitus and hearing loss are also commonly associated with perilymphatic fistulas. Some individuals find that their symptoms worsen with coughing, sneezing or nose blowing as well as with exertion and activity.
Depending on the nature and cause of perilymph fistulas conservative treatment with limited activity may resolve the symptoms. Often surgery is successful in closing the source of the fistula and resolving the symptoms.