5.2: Ear Diseases Flashcards
What is the difference between sensorineural hearing loss and conductive hearing loss?
How might you test to differentiate between the two?
Sensorineural hearing loss: arises from damage to the cochlea (inner ear) or auditory nerves delivering sound to the brain
Conductive hearing loss: arises from damage to the outer ear so sound can’t reach the inner ear
Can use a Rinne’s and Weber’s tuning fork test
If a patient has L sided conductive hearing loss what would you expect the tuning fork tests to show on each ear?
Air conduction will be reduced but the perception of sound through bone conduction will be preserved.
Rinne’s test will be negative on the abnormal ear: BC>AC on L, but AC>BC on R (normal ear)
Weber’s test will be louder in the ear with conductive loss (L ear in this case)
If a patient has L sided sensorineural hearing loss what would you expect the tuning fork tests to show?
Rinne’s test will be positive on both sides: AC>BC
Weber’s test will be louder in the unaffected ear (R ear in this case)
Describe a normal Rinnes and Webers test results
Rinnes +ve both sides (air conduction is better than bone)
Webers: midline
What term describes a benign tumour that presses on the vestibular or cochlear nerve? What symptoms can it cause?
Vestibular Schwannoma or acoustic neuroma
Can give tinnitus (ringing in the ear) or sensorineural unilateral hearing loss
Name four potential causes for conductive deafness
- Buildup of cerumen (earwax) in the outer ear
- Negative pressure in middle ear due to eustachian tube obstruction
- Otosclerosis: excessive bone growth around the stapes
- Accumulation of mucus or pus in the middle (i.e acute otitis media or glue ear)
What are some common causes of sensorineural deafness?
Damage to hair cells as a result of ageing, exposure to excessive environmental noise and ototoxic drugs
Which specific structures of the ear are involved in conductive and sensorineural hearing loss?
Conductive: External and middle ear
Sensorineural: Inner ear
What kinds of congenital problems may occur with the ear?
- Anotia: total absence of the ear
- Microtia: deformity
- Preauricular sinus
- Collaural sinuses/fistula (sinuses/openings at external auditory canal and the neck)
Where do collaural fistulas tend to occur?
Upper part of anterior border of sternocleidomastoid muscle
Name three possible types of congenital microtia which may occur in the ear
- Canal atresia
- Ossicular chain anomalies
- Facial nerve atypia
Name five kinds of acquired pinna deformities
- Trauma
- Basal cell carcinoma
- SCC
- Keratin horn
- Pinna Hematoma
What is a pinna hematoma? What does it result in and what happens if it’s left untreated?
A hematoma between the cartilage and perichondrium (which has the vessels that burst)
Since the cartilage is avascular and relies on diffusion of gases and nutrients from the perichondrium, the presence of a hematoma will lead to necrosis of the cartilage - and therefore needs to be drained immediately! If left untreated, necrosis of the underlying cartilage will lead to a misshapen pinna, or “cauliflower ear”.
Name four conditions which may affect the external ear
- Excessive wax or hair
- Swimmer’s ear; exostosis (benign outgrowth of cartilaginous tissue on bone) in ear canal
- Foreign body
- Otitis externa (including malignant version)
What is the most common condition of the external ear? otitis externa? Which signs/symptoms might it present with?
Otitis externa: Eczema/inflammation of the EAC skin +/- infection
Symptoms: itchy, pain, discharge
Signs: tragal/pinna tenderness, narrow EAM, debris/discharge in EAM
How is Otitis externa treated?
Ear drops, aural toilet and avoidance of water (prevent infection)
What’s an aural toilet??
Procedure used to clean the external auditory meatus (EAM) of the ear of wax, discharge and debris.
What is malignant otitis externa? What is it often associated with which population is more commonly affected?
NOT cancerous! It’s osteomyelitis (infection gets into the petrous temporal bone) of the ear canal. Often caused by pseudomonas and affects elderly diabetics
How does malignant otitis externa typically present and what can it progress to?
Presents with symptoms of otitis external but VERY painful
Can cause cranial nerve palsies: which may cause the experience of other symptoms such as weakness in facial muscles, loss of voice, etc and may progress to death
What is acute otitis media? Which population group is commonly affected and why?
Acute bacterial infection of the tympanic cavity causing inflammation.
Common in children due to poor immunity and a shorter, straighter eustachian tube facilitates easier spread of infection from the nasopharynx
What are some signs/symptoms of acute otitis media?
Symptoms: fever and pain (until the perforation which resolves the pain)
Signs: bulging red eardrum and pus in the middle ear
How is acute otitis media treated?
Analgesia (for pain) and antibiotics
What are some complications of acute otitis media?
- Perforation:
- Central: perforation of pars tensa
- Subtotal - CSF leakage (if associated fractured skull)
- Mastoiditis
How might a perforation of the tympanic membrane present and how might it be treated?
Usually painless discharge. It often heals spontaneously but can be treated with ear drops or surgery if large/unresolving
What happens in mastoiditis? Which population group is typically affected?
Acute suppuration (pus formation) with back pressure into the mastoid cavity and mastoid cells, happens commonly in children due to poor immunity
What are some signs/symptoms of mastoiditis?
Symptoms: earache, fever (unwell)
Signs: tender, swollen red mastoid, prominent pinna