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
How is mastoiditis treated and what possible serious complications may occur of left untreated?
Treated with antibiotics and surgical drainage
If left untreated, infection can spread from the mastoid air cells and enter the…
- Cranial cavity through the superior wall to reach the meninges, causing meningitis
- Temporal lobe causing a temporal lobe abscess
- Posterior cranial fossa where the sigmoid dural venous sinus is. Involvement of the sigmoid sinus can lead to thrombosis and can act as a portal of entry for bacteria in the bloodstream - leading to sepsis and death
What is otitis media with effusion (OME) and what can cause this condition? If left untreated, what does it lead to?
OME or “Glue ear” is when thick effusions accumulate behind the eardrum.
Caused by prolonged negative pressure in the middle ear (i.e due to Eustachian tube dysfunction or blockage secondary to enlarged adenoids) and may also have a genetic predisposition
If the eustachian tube cannot open the middle ear pressure cannot equalise with atmospheric pressure. Mucosa middle ear cells continually absorb air, therefore causing an increasingly negative pressure within the eustachian tube and middle ear. Eventually, this negative pressure causes transudate from the mucosa in the middle ear, leading to an accumulation of serous fluid (effusion). Given that this fluid cannot drain, it forms an ideal medium for pathogens to grow - and thus can predispose to recurrent ear infections (acute otitis media)
Which population is most commonly affected by OME and why?
Name four symptoms and two signs of this condition
Mostly children affected as they have narrower and more horizontal Eustachian tubes.
Symptoms: conductive hearing loss, painless (but may be associated with AOM which is painful), speech and language delay in younger children and educational problems in older children
Signs: TM dull and retracted, effusion/bubbles
How is OME managed and how long do they typically last?
- Watch and wait 3 months
Doesn’t cure but helps with education until child grows out of it:
- Otovent
- Grommets
- Hearing aids
How do otovents and grommets work?
Both try to equalize the pressure (between middle ear and nasopharynx) so that the sticky fluid can drain
Otovent: an autoinflation device which uses a pressurised balloon to open the Eustachian tubes
Grommet: a ventilation tube surgically implanted in the eardrum
Other than glue ear, what else may occur as a result of chronic negative middle ear pressure?
- Tympanic Retraction: Negative middle ear pressure -> retraction pockets
- > dead skin cells accumulate in the pockets -> - Cholesteatoma: necrotic mass of dead skin
- > erosion of middle ear structures and bone via lytic enzymes
What are three signs and symptoms of a cholesteatoma?
Signs: conductive hearing loss, discharge/keratin debris, attic crust/polyp which has grown over the cholesteatoma
Symptoms: hearing loss, smelly discharge, recurrent infections
What are some complications of a cholesteatoma and how is it usually treated?
Complications are brain infections/abscesses so treatment is usually surgery
What clue in an ear examination would identify cholesteatoma?
Crusts in the pars flaccida (aka “attic”) which can hide a cholesteatoma brewing underneath!
Which nerve is most commonly affected in middle ear disease and why?
Facial nerve dysfunction/palsy as it runs through the middle ear in the internal acoustic meatus
What is otosclerosis and what are some predisposing factors?
When vascular spongy bone replaces normal bone around the stapes footplate
More common in women and with a FH
What are some symptoms/signs of otosclerosis?
Symptoms: hearing loss due to stiffened ability for stapes to vibrate
Signs: conductive hearing loss, schwartz sign in 10%: reddish-blue discoloration of the promontory and oval window (seen during an otoscopic examination)
How is otosclerosis usually treated/managed?
Stapedectomy (to replace stapes bone) and hearing aids
Where in the body is ear pain commonly referred from?
- Mouth: Teeth and tongue
- Throat and neck; pharynx, tonsils
- Cervical spine
- Temporomandibular joint (TMJ)
Which nerves when damaged (i.e trauma, inflammation or neoplasms) leads to referred pain on the ipsilateral ear?
Anywhere along the course of the trigeminal, facial, glossopharyngeal, vagus or cervical nerves C2 and C3
What commonly causes pruritus (itchiness) of the ear?
Primary disorder of the external ear or as a result of discharge from the middle ear
What is otorrhea and what does it generally indicate?
Otorrhea is discharge from the ear, and indicates acute or chronic infection
What might bloody discharge from the ear be indicative of?
Leakage of CSF secondary to a skull fracture
Which syndrome is commonly associated with referred ear pain/problems and what causes it?
Ramsay Hunt syndrome: when a shingles outbreak affects the facial nerve near one of the ears
What does the ability to ear depend on? What is the human hearing range and when does sound become painful?
Pitch (frequency): Hz
Loudness: dB
Human range: 20-20,000 Hz
>90 dB (shouting) painful
Generally, how might sensorineural hearing loss occur?
Congenital (1:1000 have profound hearing loss) or acquired loss of hair cells
List four causative examples for bilateral sensorineural hearing loss and two for unilateral sensorineural hearing loss. Which type is more common?
Bilateral: More common
- Infection: measles, meningitis
- Presbyacusis: hearing loss with age
- Noise induced hearing loss
- Ototoxic drugs
Unilateral:
- Acoustic neuroma (vestibular schwannoma)
- Menieres disease
Name one example of an ototoxic drug
Gentamicin
When would you normally investigate sensorineural hearing loss and how might you investigate it? What would you want to exclude?
MRI if the internal acoustic meatus is unilateral to exclude acoustic neuroma/vestibular shwannoma
How is sensorineural hearing loss managed?
Hearing aids and cochlear implants with profound hearing losses
List the four main symptom complexes of true rotational vertigo in vestibular disease. What is the duration of the vertiginous attack associated with each type?
- Benign positional Vertigo: sec-minutes
- Meniere’s disease: min-hours
- Labyrinthine failure: >24 hours
- Vertiginous migraine: random and with other symptoms
How is vertigo diagnosed?
History of vertiginous attacks
What precipitates benign positional vertigo and what is the underlying pathology?
Precipitated by head movement which causes otolith displacement, generating a spinning sensation.
How is vertigo treated?
With repositioning maneuvers
What is the trilogy associated with Meniere’s disease and what symptoms are associated with this disease?
Trilogy of vertigo, tinnitus and hearing loss!
Associated with
- Vomiting
- Aural/ear fullness
- Random attacks of vertigo which last minutes-hours
What causes Meniere’s disease?
Endolymphatic hydrops; excess fluid/pressure in the endolymph which damages the membranous labyrinth
Name six causes of vertigo unrelated to the vestibular structure!
V: vascular E: epilepsy R: Receiving treatment T: tumours, trauma, thyroid I: Infections G: Glial (MS) O: Ocular
What might a keratin horn be an early indication of?
A SCC
When is wax a problem?
If it’s touching the eardrum or completely blocking the ear canal
What is the difference between acute otitis media and otitis media with effusion?
AOM relates to any inflammatory or infective problem of the middle ear, but OME doesn’t mean there’s an acute infection or inflammation. OME is characterised by chronic inflammation and chronic buildup of fluid within the middle ear. While this can occur following a middle ear infection (i.e AOM), there are other reasons OME can arise. Glue ear is not usually painful
What is tinnitus and what is it often associated with? What is the risk of developing it at some point and the risk of having it persistently?
Perception of hearing sound in the absence of any external sound. Usually but not alway a symptom associated with hearing loss
Common: 30% lifetime, 10% persistent
A stapedectomy involves the surgical removal of the stapes, which attachments must be divided to remove the stapes?
Three attachment points:
- Incudostapedial articulation (ball-and-socket joint) between stapes and incus
- Base/footplate of stapes is attached to the oval window (of the medial wall of the tympanic cavity)
- Insertion of stapedius muscle to the neck of the stapes
What is another term for the oval window?
Fenestra vestibuli
Which branch of the facial nerve passes through the tympanic cavity?
The chorda tympani
