Section 3

35M involved in a road traffic accident complains of hearing loss in his left ear

LEFT temporal bone fracture
LEFT dead ear

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Describe what imaging modality this is?

  • High resolution CT scan

 

What is the diagnosis?

  • Temporal bone fracture – otic capsule disrupting

Describe the classification for this type of injury

  • Otic capsule sparing or otic capsule disrupting
  • Longitudinal and transverse – in relation to the petrous bone long axis

Describe the pure tone audiogram.

  • Normal thresholds in right ear
  • Left ear – profound hearing loss/dead ear at all frequencies, sensorineural hearing loss

What other symptoms might this patient have?

  • Vertigo
  • Facial nerve palsy
  • CSF leak

The patient was wondering if his hearing would recover, what would you advise? What type of hearing aid device may be of benefit?

  • This is permanent hearing loss, may have some improvement
  • Contra-lateral Routing of Signal (CROS) hearing device or bone anchored hearing aid (BAHA) may help

Supporting Information

Information

Temporal bone – contains; squamous temporal bone, petrous temporal bone, stylomastoid foramen, inner auditory meatus, mastoid bone, styloid process.

The internal auditory meatus exits the posterior fossa surface of the temporal bone. Contains:

  • Vessels – labyrinthine artery from basilar artery
  • Nerves – vestibulocochlear nerve, facial nerve, vestibular ganglion

Temporal bone fracture 

  1. Longitudinal (80%) – from a lateral skull blow. Tympanic membrane can be torn and haemotympanum may be evident. A CSF leak may also be present. Facial nerve injury is unlikely.
  2. Transverse (20%) –  from an anterior-posterior skull blow. There is usually an in-tact tympanic membrane but facial nerve damage may be evident, along with sensorineural hearing loss, vertigo and CN palsy. Often affects cochlear and vestibular organs. No recovery, BAHA will not help.

Otorrhoea – if clear consider a CSF leak. Investigate:

  1. Beta-2 transferrin
  2. Glucose – No longer used routinely
  3. Beta-trace protein (prostaglandin D synthase)

Presentation – bloody otorrhoea, headache, hearing loss, tinnitus, dizziness, facial nerve palsy, nystagmus, haemotympanum, Battle sign – mastoid bruising, Racoon eyes – periorbital eccymosis. They may have stepping of the EAC and traumatic perforation.

Facial nerve damage – if immediate – may warrant decompression. A delayed palsy likely to resolve over time.

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