ENT - Hearing Loss Flashcards
What are the main types of hearing loss?
Conductive hearing loss - problem with sound traveling from the environment to the inner ear.
Sensorineural hearing loss - problem with the sensory system or vestibulocochlear nerve in the inner ear.
Sections of the ear.
Symptoms associated with hearing loss.
- tinnitus
- vertigo
- pain
- discharge
- neurological symptoms
What examination can be used to differentiate between sensorineural and conducting hearing loss?
NB: Spiderman shoots a web (Weber’s) right into the middle of someones face.
Normal hearing - findings.
a) Rinnes test
b) Weber’s test
a) AC > BC
b) no lateralisation
Sensorineural hearing loss - findings.
a) Rinnes test
b) Weber’s test
b) AC > BC (false normal in affected air)
b) sound lateralises to the normal ear
Conductive hearing loss - findings.
a) Rinnes test
b) Weber’s test
a) BC > AC in affected ear
b) sound lateralises to the affected ear
Causes of adult-onset sensorineural hearing loss.
- presbycusus (age-related)
- Ménière’s disease
- labyrinthitis
- acoustic neuroma
- neurological conditions (e.g. stroke, multiple sclerosis, brain tumour)
- infections (e.g. meningitis)
- medications
What medications can cause sensorineural hearing loss?
- furosemide
- gentamicin
- cisplatin
Causes of conductive hearing loss.
- ear wax
- infection (e.g. otitis media, otitis externa)
- fluid in middle ear
- Eustachian tube dysfunction
- perforated tympanic membrane
- otosclerosis
- cholesteatoma
- exostoses
- tumours
What is audiometry?
Testing a patient’s hearing by playing a variety of tones and volumes using headphones, and an oscillator.
It can help identify and differentiate conductive and sensorineural hearing loss.
Which symbols are used to plot on an audiogram?
a) left-sided air conduction
b) right sided air conduction
c) left sided bone conduction
d) right sided bone conduction
a) X
b) O
c) ]
d) [
What audiometry findings are consistent with normal hearing?
All reading will be between 0 and 20 dB
What audiometry findings are consistent with sensorineural hearing loss?
Air conduction and bone conduction are more than 20dB.
This may affect one side, one side more than the other or both sides equally.
What audiometry findings are consistent with conductive hearing loss?
Bone conduction readings are normal (0-20dB).
Air conduction readings more than 20dB.
What audiometry findings are consistent with mixed hearing loss?
Both air and bone conduction readings >20dB.
There will be a difference of >15dB between air and bone conductance (BC > AC)
Pathophysiology of presbycusis.
Age-related loss of hair cells and neurones in the cochlea results in a sensorineural hearing loss.
It tends to affect high-pitched sounds first, with a gradual and symmetrical hearing loss.
Presbycusis - risk factors.
- increasing age
- family history
- loud noise exposure
- diabetes
- hypertension
- ototoxic medications
- smoking
Symptoms of presbycusis.
Gradual and insidious hearing loss:
- high pitched sounds first
- speech difficult to hear
- missing details of conversations
- tinnitus
NB: Patients may present with concerns about dementia, when the issue is hearing loss.
Diagnosis of presbycusis.
Audiometry
Sensorineural hearing loss pattern; worsening hearing loss at higher frequencies.
Management of presbycusus.
Support the person to maintain normal functioning:
- reduce ambient noise during conversations
- hearing aids
- cochlear implants
What is sudden sensorineural hearing loss?
Hearing loss over less than 72 hours, unexplained by other causes.
Causes of sudden sensorineural hearing loss.
- idiopathic (>90%)
- infection
- ménière’s disease
- ototoxic medications
- multiple sclerosis
- stroke
- acoustic neuroma
Investigations of sudden sensorineural hearing loss.
Audiometry.
MRI or CT head may be used if a stroke or acoustic neuroma are being considered.
Management of acute sensorineural hearing loss.
Immediate referral to ENT for assessment.
Idiopathic SSNHL can be treating with steroids under the guidance of ENT:
- oral
- intra-tympanic
What is an acoustic neuroma?
A benign tumour of the Schwann cells surrounding the vestibulocochlear nerve.
Acoustic neuromas occur at the _____ angle.
Cerebellopontine angle.
Acoustic neuromas are usually unilateral.
What is the association of bilateral acoustic neuromas?
Neurofibromatosis type II
Symptoms of acoustic neuroma.
Gradual onset of:
- unilateral sensorineural hearing loss
- unilateral tinnitus
- dizziness or imbalance
- fullness in the ear
They can also be associated with facial nerve palsy if the tumour grows large enough to compress the facial nerve.
Investigating acoustic neuroma.
Audiometry revealing a sensorineural pattern of hearing loss.
Brain imaging (MRI or CT) to establish a diagnosis.
Management of acoustic neuroma.
Conservative management with monitoring if there are no symptoms.
Surgery to remove the tumour (partial or total removal).
Radiotherapy to reduce the growth.
Risks associated with treatment of acoustic neuromas (radiotherapy or surgery).
Vestibulocochlear nerve injury:
- permanent hearing loss
- dizziness
Facial nerve injury:
- facial weakness
Facial nerve pathway.
- Exits brainstem at cerebellopontine angle
- Passes through temporal bone and parotid gland
- Divides into branches*
*To Zanzibar By Motor Car
Function of the facial nerve.
Motor:
- facial expression
Sensory:
- taste from anterior 2/3 of tongue
Parasympathetic:
- submandibular and sublingual salivary gland
- lacrimal gland
How to differentiate between UMN and LMN facial nerve palsy.
UMN - forehead sparing - urgent referral with suspected stroke.
LMN - forehead not spared.
Causes of UMN facial nerve palsy.
- stroke
- tumour
- motor neurone disease
Treatment of Bell’s palsy.
The majority of patients fully recover over several weeks; a third are left with some residual weakness.
NICE recommend considering prednisolone as treatment.
Lubricating eyedrops; eye can be taped closed at night.
What is Ramsay-Hunt Syndrome?
Varicella Zoster Virus (VZV) reactivation in the lower motor neurone of the facial nerve.
Presents with a painful and tender rash in the:
- ear canal
- pinna
- ear
- anterior two-thirds of tongue
Treatment of Ramsey-Hunt syndrome.
Treatment within 72 hours of symptom onset:
- prednisolone
- aciclovir
Patients also require lubricating eye drops.
Causes of LMN facial nerve palsy.
- idiopathic (Bell’s palsy)
- otitis media
- diabetes
- leukaemia
- acoustic neuroma
- trauma
Pathophysiology of otosclerosis.
Abnormal bone remodelling to the malleus, incus and stapes.
Results in stiffening and fixation, preventing the auditory ossicles from transmitting sound effectively to the oval window of the cochlea.
This results in a conductive hearing loss.
Presentation of otosclerosis.
Unilateral or bilateral:
- conductive hearing loss
- tinnitus
Tends to affect the hearing of lower-pitched sounds more.
Why may patients with otosclerosis talk quietly?
Due to conductive hearing loss with intact sensory hearing, the patients can experience their voice as being loud compared to the environment (BC > AC).
This can lead to them talking quietly.
Investigating otosclerosis.
Audiometry revealing a conductive hearing loss, greater at lower frequencies.
High-resolution CT scan can detect bony changes, but isn’t always required.
Management of otosclerosis.
Conservative: use of hearing aids.
Surgical:
- stapedectomy
- stapedotomy
What is the normal function of ear wax?
Has a protective effect to prevent infection in the ear canal.
What is the most common cause of conductive hearing loss?
Impacted ear wax:
- conductive hearing loss
- discomfort in the ear
- feeling of fullness
- pain
- tinnitus
Otoscopic appearance of earwax.
May completely cover the tympanic membrane, preventing assessment of the tympanic membrane and middle ear.
Management of earwax.
Ear drops - olive oil.
Ear irrigation (squirting water in the ears to clean away the wax).
Microsuction (suck out the wax).
Contraindications to ear irrigation.
- perforated tympanic membrane
- infection
Microsuction can be performed by a specialist if there are contraindications.
What is otitis externa?
Inflammation of the skin in the external ear canal.
Common causes of bacterial otitis externa.
- Psuedomonas aeruginosa
- Staphylococcus aureus
Causes of otitis externa.
- bacterial infection
- fungal infection (?recent abx)
- eczema
- seborrhoeic dermatitis
- contact dermatitis
Symptoms of otitis externa.
- ear pain
- discharge
- itchiness
- conductive hearing loss
Examination findings in otitis externa.
- erythema and swelling of ear canal
- tenderness of ear canal
- pus or discharge
- lymphadenopathy in neck or ear
Investigations of otitis externa.
Diagnosis can be made clinically with otoscopy.
Ear swab can be used to identify the causative organism.
Management of otitis externa.
Acetic acid 2% spray.
Available over the counter as EarCalm spray.
Give self care advise - Managing Your Common Infection (Self Care) leaflet.
What is malignant otitis externa?
A life-threatening form of otitis externa - the infection spreads to the temporal bones surrounding the ear canal and skull.
Risk factors for malignant otitis externa.
Underlying risk factors for severe infection:
- diabetes
- immunosuppressed (e.g. chemotherapy)
- HIV
Presentation of malignant otitis externa.
- persistant headache
- severe ear pain
- fever
Granulation tissue at the junction between the bone and cartilage in the ear canal.
Management of malignant otitis externa?
Emergency management:
- admission to hospital under ENT team
- IV antibiotics
- imaging (CT or MRI)
Complications of malignant otitis externa.
- facial nerve damage
- meningitis
- intracranial thrombosis
- death
What is otitis media?
Infection of the middle ear - the space between the tympanic membrane and the inner ear.
Causes of otitis media.
Streptococcus pneumoniae (most common).
Other common causes:
- Haemophilus influenzae
- Moraxella catarrhalis
- Staphyloccocus aureus
Presentation of otitis media.
- ear pain
- reduced hearing
- fever
NB: viral upper respiratory tract often precedes bacterial infection of the middle ear, so may have recent coroyzal symptoms.
Examination of otitis media.
Otoscope - tympanic membrane:
- bulging
- red
- inflammed
Prognosis of otitis media without antibiotics.
Most cases resolve within around 3 days.
Antibiotics do not usually make a difference to symptoms or complications.
Simple analgesia can be used for pain or fever.
Options for antibiotic prescription in otitis media.
- immedaite antibiotics (significant comorbidities, systemically unwell)
- delayed prescription (collect after 3 days if symptoms have not improved or worsened)
- no antibiotics
Complications of otitis media.
- otitis media with effusion
- hearing loss
- perforation of tympanic membrane
- labyrinthitis
Rare complications:
- mastoiditis
- abscess
- facial nerve palsy
- meningitis
What is the function of the Eustachian tube?
Equalise the pressure in the middle ear, and drain fluid from the middle ear.
Causes of Eustachian tube dysfunction.
- viral URTI
- allergies (e.g. hayfever)
- smoking
Presentation of Eustachian tube dysfunction.
- reduced hearing
- popping sensation in ear
- fullness sensation in ear
- pain or discomfort
- tinnitus
Otoscopy findings in Eustachian tube dysfunction.
Otoscopy may appear normal - other causes include otitis media.
Investigating Eustachian tube dysfunction.
- tympanometry
- audiometry
- nasopharyngoscopy (endoscopic camera through nose to inspect Eustachian tube openings)
- CT scan (structural pathology)
What is tympanometry?
Insertion of a device into the external auditory canal, which introduces pressure difference within the canal.
A sound is sent in the direction of the tympanic membrane, and the amount of sound reflected back is measured.
The amount of sound absorbed by the tympanic membrane is known as the admittance.
Normal tympanometry results.
Peak admittance when the pressure in the ear canal matches ambient air pressure.
Tympanometry results suggestive of Eustachian tube dysfunction.
Peak admittance with negative ear canal pressures.
NB: Air pressure in the middle ear will be lower than the ambient air pressure, as new air cannot get through the tympanic membrane to equalise the pressures.
Management of Eustachian tube dysfunction.
- no management (wait for spontaneous resolution)
- valsalva manouevre
- decongestant nasal sprays
- antihistamines
- surgery in persistant cases
Surgical options for Eustachian tube dysfunction.
Grommets
Usually safe, minimal complications and fall out on their own within 18 months.
Pathophysiology of a cholesteatoma.
Eustachian tube dysfunction causes a negative pressure in the middle ear, resulting in retraction of the tympanic membrane.
The squamous epithelial cells continue to proliferate, causing a collection of them in the middle ear.
It is non-cancerous, but is locally invasive.
Presentation of a cholesteatoma.
- foul discharge from ear
- unilateral conductive hearing loss
As the cholesteatoma expands into surrounding tissue, other symptoms may develop:
- infection
- pain
- vertigo
- facial nerve palsy
Management of cholesteatoma.
Referral to ENT.
CT head to confirm diagnosis and surgical planning.
Surgical removal of cholesteatoma.
What is acute mastoiditis?
Complication of acute otitis media where the infection spreads from the middle ear into the mastoid air cells.
Risk factors for mastoiditis.
- recurrent AOM
- children <2 years
- learning difficulties
- immunocompromised
- anatomical abnormalities (e.g. cholesteatoma)
Features of mastoiditis.
A recent episode of otitis media plus:
- proptosed auricle
- post-auricular swelling
- post-auricular erythema
- post-auricular tenderness
Laboratory investigations of mastoiditis.
- FBC (?leukocytosis)
- U&Es (?baseline renal function)
- CRP (?inflammation)
- lactate (?sepsis)
- blood cultures (?identify organism)
Imaging of mastoiditis.
CT of the temporal bones - reveals mastoid air cell opacification due to fluid collection.
Immediate management of mastoiditis.
- A-E approach resuscitation
- Initiation of sepsis 6
- NBM
- senior paediatric, ENT and neurosurgical input
- analgesia
Medical management of mastoiditis.
Broad spectrum IV antibiotics as per local microbiology guidelines.
Surgical management of mastoiditis.
- tympanocentesis
- grommet insertion
Purulent middle ear fluid should be sent to microbiology for microscopy, culture and sensitivity.
Complications of mastoiditis.
- facial nerve palsy
- bacterial labyrinthitis
- abscess
- venous sinus thrombosis
- death
- conductive hearing loss
What is tinnitus?
The persistent addition sound that is heard in the surrounding environment:
- ringing
- buzzing
- hissing
- humming
Pathophysiology of tinnitus.
Result of a background sensory signal produced by the cochlea, that is not filtered out by teh central auditory system.
In a quiet enough environment, everyone will experience some tinnitus - this will become more prominent the more attention it is given.
What is primary tinnitus?
No identifiable cause - often occurs with sensorineural hearing loss.
