Flashcards in 12 - Head & Neck - The Ear 2 Deck (33):
What part of the labyrinth contains receptors detecting rotational acceleration?
- Semicircular ducts
How should a normal, healthy tympanic membrane appear during otoscopy?
Blood vessels around perimeter
What are the main causative organisms of otitis externa?
- Pseudomonas aeruginosa
What is a auricular haematoma? What is the complication of this if it isn't treated rapidly?
Blood between perichondrium + auricular cartilage
Fibrosis and new asymmetric cartilage formation
*Must be drained promptly*
Why is otitis media more common in children?
- Eustachian tube is shorter + more horizontal
- Allows infection to spread from nasopharynx more easily
Describe the appearance of a tympanic membrane during otitis media (no effusion):
- Loss of normal landmarks
How can otitis media lead to inflammation of the facial nerve?
The facial nerve runs in a bony canal on the posterior wall of the middle ear, and gives out Chorda Tympani branch here, which can become inflamed/infected
= loss of taste first
List some complications of otitis media:
- Tympanic membrane perforation
- Facial nerve inflammation
- Hearing loss
- Brain abscess
What are the symptoms of mastoiditis?
- Ear pushed forward
- Redness behind pinna
What is a cholesteatoma?
Slowly growing collection of abnormal keratinised skin cells within the middle ear
How does a cholesteatoma usually form?
- Chronic/recurring otitis media + ET blockage
= Decreased pressure within middle ear, draws eardrum inwards, creates small pocket at top of tympanic membrane
- Epithelia are trapped, collect and proliferate
What is an acoustic neuroma?
Benign tumour of sheath covering CN VIII
What are the symptoms associated with an acoustic neuroma?
- Gradual hearing loss
- Facial weakness (damaged CN VII)
- Facial parasthesia (damaged CN V)
What is Meniere's disease?
Disorder of inner ear due to excess endolymph, causin progressive destruction of ducts and membranes
What are the symptoms associated with Meniere's disease?
- Hearing loss
- Low-pitched tinnitus
- Feeling of pressure/fullness in ear
Describe the appearance of a tympanic membrane affected by otitis media with effusion:
- Straw coloured
If the eustachian tube becomes blocked, why does the pressure within the middle ear drop?
Cells within the middle ear absorb air = reduced pressure in middle ear cavity
What is otitis media with effusion?
Build up of fluid and negative pressure in middle ear, due to eustachian tube dysfunction (not infection)
How does otitis media with effusion cause a loss of hearing? How it this condition managed?
Build up of fluid reduces ossicle movement, so sound is not amplified.
- Usually resolves spontaneously < 3 months
- If chronic = grommets to allow drainage and pressure equalisation
Define conductive hearing loss:
Hearing loss due to pathology in the external or middle ear.
Define sensori-neural hearing loss:
Hearing loss due to pathology in the inner ear or CN VIII
How is Weber's test conducted?
- Place vibrating tuning fork on center of head
- Ask whether the sound is equal in both ears, or louder in one
If Weber's test results in the sound being louder in the right ear, what could this suggest?
- Sensorineural loss in L ear
- Conductive loss in R ear
How is Rinne's test conducted?
- Hold vibrating tuning fork in front of ear
- Hold vibrating tuning fork on mastoid process
- Ask which sounded louder
What is the outcome of Weber's test if there is no disease present?
Sound will not equalise to one side, they are equal
What is the outcome of Rinne's test if there is no disease present?
Air > Bone
If someone has a conductive hearing loss of their R ear, what will the results of Weber's + Rinne's tests be?
Weber's = Localise to R ear
Rinne's = In R ear: Bone > Air
If someone has a sensorineural hearing loss of their L ear, what will the results of Weber's + Rinne's tests be?
Weber's = Localise to R ear
Rinne's = In L ear: Air > Bone
What are the 3 branches of the facial nerve which arise on the petrous part of the temporal bone?
1) Greater petrosal
2) Nerve to Stapedius
3) Chorda Tympani
Reactivation of varicella zoster virus in the facial nerve can cause which complication?
What is the main difference between shingles and this complication?
Ramsay Hunt syndrome = facial nerve palsy + rash around ear
Shingles= affects sensory nerves
RH syndrome = affects sensory + motor
What is the nerve innervation to the auricle?
- Greater auricular nerve C2/3
- Auriculotemporal nerve CN V3
What is the nerve innervation to the tympanic membrane?
Externally : Mainly CN V, some CN X
Internally : CN IX