Perilymph fistula

• anatomy
  • the inner ear which is encased in bone is seperated from the middle ear at two thin membranous locations called the oval and round windows (1)
  • rupture of the oval or round window results in leakage of perilymph into the middle ear
  • this is termed a perilymphatic fistula
• causes:
  • usual cause is a sudden change in atmospheric pressure due to
    • flying
    • diving (otitic barotrauma)
  • sudden physical exertion
  • excessive straining(e.g.childbirth)
  • stapedectomy
• clinical features incude
  • sudden or fluctuating hearing loss (1)
  • vertigo
  • lightheadedness
  • disequilibrium
  • motion intolerance
  • nystagmus
• investigations and diagnosis
  • the following tests help in the diagnosis (1)
    • audiogram
    • tympanogram
    • electronystagmography (ENG)
    • electrocochleography (ECoG)
    • CT scan of the temporal bone
    • the fistula test is positive
• treatment
  • bedrest
  • urgent referral to an otologist
  • definitive treatment is surgical
    • procedure
      • takes about 30 minutes
      • the ear drum is lifted up through the ear canal and the round and oval windows are patched

Reference:

(1)diving-related diseases of the ear, Department of Otolaryngology-Head & Neck Surgery, University of California, Irvine© 2006 The Regents of the University of California