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tinnitus_pulsatile

whooshing or pulsatile tinnitus

introduction

  • most tinnitus originating in the auditory system is due to a sensorineural hearing loss with resulting dysfunction within the auditory system
    • mostly this is high pitched
    • Ménière's disease is generally low pitched tinnitus
    • a whooshing sound is generally regarded as being pulsatile tinnitus and is often due to vascular noises and these are generally of more acute concern than normal tinnitus for an acutely serious cause
    • some vascular causes are not pulsatile such as venous hum and tinnitus due to atherosclerotic plaque narrowing of arterial vessels
      • venous hum is soft, low-pitched hum (usually bilateral but may be unilateral) which can change with:
        • pressure over the jugular vein may reduce it or stop it
        • change in head position
        • activity
    • patients with vascular causes generally do not have other otologic symptoms due to the vascular cause such as deafness, vertigo or fullness in the ear however, these may occur in patients with paragangliomas or for other reasons

Aetiology

  • audible bruits
    • turbulent blood flow in arteries near the temporal bone can cause audible bruits
  • almost half have defined vascular aetiologies such as:
    • dural arteriovenous fistula
      • rare, tend to develop more often in those aged over 50yrs and usually form after a venous thrombosis (eg. post head injury, post-op neurosurgery, CNS infections, etc)
      • may cause headache, visual disturbance and stroke-like symptoms1)
    • carotid-cavernous sinus fistula
      • rare, tend to develop more often in those aged over 50yrs and usually form after a venous thrombosis (eg. post head injury, post-op neurosurgery, CNS infections, etc)
      • may cause exophthalmos and increased ocular tearing and reddening of eye(s) along with blurred vision and eye pain
      • may also cause stroke-like symptoms, N/V or seizures2)
    • congenital A-V malformations
      • tend to present in those aged under 50yrs
  • other vascular-related causes include:
    • paraganglioma - these are highly vascular
  • venous hums:
    • benign raised intracranial hypertension
    • systemic hypertension
    • dehiscent or dominant jugular bulb (abnormally high placement of the jugular bulb)
  • neuro-muscular causes:
    • these generally cause a clicking sound
    • spasm of one or both of the muscles within the middle ear (the tensor tympani and the stapedius muscle)
      • may also complain of hearing loss or aural fullness
      • tympanometry and otoscopy can be particularly useful in diagnosis
      • may be caused by multiple sclerosis (MS) or other neurologic conditions
    • myoclonus of the palatal muscles that attach to the Eustachian tube orifice
      • may be caused by multiple sclerosis (MS) or other neurologic conditions such as brainstem microvascular issues, metabolic or toxic neuropathies
  • respiratory “pulsations” similar to the roar of waves at a beach “ocean roar”
    • patulous Eustachian tube that remains abnormally patent, allowing too much and then too little aeration of the middle ear space with respiration, tends to disappear when lying down
    • also causes unusual awareness of their own voice (autophony) and ear discomfort
    • due to significant weight loss or after external beam radiation to or near the nasopharynx
  • machine-like grinding
    • chondrosarcoma
    • aberrant carotid artery
    • endolymphatic sac tumors

Clinical Mx in the ED

  • clinical assessment for evidence of diagnostic clues
    • pulsatile vs clicking vs hum vs ocean roar vs machine-like grinding
    • effects of posture
    • presence of otologic symptoms or signs: deafness, vertigo, etc
    • presence of bruits or hypertension
    • presence of cranial nerve pathology or other neurology
  • frequent or constant pulsatile tinnitus can herald a potentially life-threatening illness
    • consider CT brain with either CT or MRI angiography (or both)
      • MRA is generally the preferred option if a vascular cause is suspected
      • High-resolution CT scanning is required if a paraganglioma is suspected
    • all of these patients require evaluation by an otolaryngologist or neurologist
tinnitus_pulsatile.txt · Last modified: 2020/05/17 12:56 by gary1