Week 5b - TB Trauma Flashcards
What are the 4 types of temporal bone (TB) trauma?
Blunt (no penetration)
Penetrating (e.g. gunshot)
Compressive (gradual; multidirectional)
Barotrauma (pressure change)
Which population is most likely to suffer barotrauma, and from what?
Men
20-40 years old
Automobile accidents
Which of the following can be affected by TB Fractures?
a) external ear
b) middle ear
c) inner ear
d) internal carotid artery
e) mastoid
All of them
What are the specific structures at risk in a TB fracture?
- cranial nerves
- cochlea
- labyrinth
- ossicles
- TM
- carotid artery
- jugular vein
What are the two ways of classifying TB trauma?
According to the direction of the fracture (traditional)
- longitudinal vs transverse
According to the structures involved (newer scheme)
- disruption of otic capsule vs sparing of otic capsule
Which is more common: longitudinal or transverse fractures? Which involves facial nerve injury 50% of the time?
- Longitudinal is more common
- Transverse involves facial nerve injury in half of the cases
What external signs would we expect to see during a physical examination of someone with a TB fracture?
External ear:
- lacerations
- hematoma (Battle’s sign behind the ear)
- bony deformity
- CSF leak
- otorrhea (clear? bloody? Through EAM or mouth)
- periorbital hematomas (raccoon eyes)
What audiometric and imminence profiles would we expect with TB trauma?
- variety of audiometric profiles
- imminence may be reduced with fluid in ME or hyper-mobile with ossicular disarticulation
What would we expect to see with otoscopy for a TB trauma injury?
- hemotympanum (purple TM)
- TM perforation
- EAC laceration (blood in EAM)
- ossicular disruption (ossicles protruding through TM)
Which professional would receive a referral to look into disequilibrium, cranial nerves, CT scans, etc in the case of TB fracture?
Neuro-otologist
High resolution CT scans of temporal bones are done if a fracture is suspected. What signs or symptoms might prompt this?
- facial paralysis
- CSF leak
- disruption of superior wall of EAC
- suspected vascular injury
If the nose represents “12 o’clock” in the axial plane, a fracture running from 1 - 8 o’clock would be _______ (longitudinal/transverse)
Longitudinal
How would an Otic Capsule Sparing Longitudinal Fracture present? What structures would be involved?
Presentation:
- conductive component, FN paresis (20% of cases)
Structures:
- EAC, TM, ME (hemorrhage), ossicles, FN
In a longitudinal TB fracture, the conductive component may be d/t hemotympanum, TM perforation, and ossicular chain disruption. What is the audiologist’s job regarding this?
Serial monitoring
- hemotympanum often resolves within a month
- TM perforation often resolves within 3 months (IF NOT, tympanoplasty)
- ossicular chain may heal spontaneously (ossiculoplasty or ossicle replacement may be needed)
What might indicate ossicular chain damage?
Residual Conductive HL following resolution of hemotympanum
- exploratory tympanotomy indicated if 30 dB CHL persisting >2months after injury (contraindicated if CHL in only hearing ear)
