ENT Flashcards
what is the external acoustic metatus made up of
outer 1/3 = cartilage
inner 2/3 = temporal bone
2 parts of the external ear
auricle/pinna
external acoustic meatus
which muscles contract in response to loud noise
tensor tympani and strapedius
inhibit vibrations of malleus, incus and stapes
how to position ear to straighten canal in adults vs children
adults = posteriorly and superiorly
children = posteriorly and inferiorly
tuning fork Hertz for rinne’s test
512 Hz
Utenberger’s test
patient marches on the spot with closed eye
if vestibular dysfunction will turn towards the lesion
decibels that a patient can hear at different distances
whisper at arm’s length (60cm) = >30 decibels
whisper at 15cm or conversational voice at 60 then can hear between 30-70 dB
Rinne negative
if sound is louder on the mastoid process
= conductive deafness
normal hearing
Normal = between 0-20dB in all frequencies - 20 and 20,000Hz
audiometry
present a pure tone at an audible level
decrease by 10 till can’t hear
then increase by 5 till they hear
To check for accuracy, should decrease 10 dB one more time to check for no response, then increase by 5 dB increments until the patient responds again to the signal
both a bone conduction threshold and air conduction is tested
presbycusis on an audiometry graph
Presbycusis usually affects the high frequencies more than the low
will show tailing off of both air and bone conduction at higher frequencies
Noise induced hearing loss on an audiometry graph
shows a sharp dropping off as you reach higher frequencies
if a hearing loss is noise induced you would expect that the sounds have to be made louder before they are heard at 4KHz than at any other frequency. This leads to a dip in the graph
symmetrical hearing loss
We consider a hearing loss to be symmetrical if the points for each ear occur within 10dB of each other
what does impedance audiometry encompass
tympanometry - measures pressure in the middle ear
measuring the reflex of the strapedius
eustachian tube funciton test
cause of a flat line on tympanometry waveform
middle ear effusion - EAC volume is normal
tympanic membrane
perforation or patent gromet- EAC volume >1cm3
peak on tympanometry occurs at negative pressure causes
eustacian tube dysfunction
uses of impedence audimetry
Is mainly used to determine the cause for conductive hearing loss
- presence of infectious fluids in the middle ear
- otitis media with effusion – glue ear
- checking the patency of a grommet
- to check for microscopic perforation of tympanic membrane
- hypertrophy of adenoids or tonsils
- Eustachian tube dysfunction
- otosclerosis
- ossicular chain fracture
- facial palsy
external ear causes of ear pain
chondritis (inflammation of the cartilage of the pinna - typically occuring after trauma/a cut - Psueodomans, staph or strep) pericondritis (inflammation of the pericondrium - a layer of CT which surrounds the cartilage) otitis externa foreign body trauma herpes zoster neoplasm impacted cerumen (earwax)
referred causes of otalgia
salivary glands - calculi or infection
temporal arteritis
cranial nerve referred pain e.g. with trigeminal neuralgia (5) or Ramsay Hunt syndrome (7)
TMJ dysfunction
management of cerumen impaction
flush it out with a syringe filled with water or saline (the wax can be softened first with oil or bicarbonate drops - give for 2-3 days then put in water then suck all out)
or manual removal e.g. with alligator forceps
treatment of chrondritis or perichondritis
drain pus from an abscess if present
antibiotics like levofloxacin
external ear otorrhea
e.g. otitis externa
will only produce a small amount of discharge compared to middle or inner because there are no mucinous glands
types of discharge with middle ear otorrhea
serosanguinous suggests a granular mucosa of chronic otitis media
offensive discharge = choleastoma
inner ear otorrhea
CSF otorrhea may follow discharge
suspect if you see the halo sign on filter paper
conductive hearing loss causes
- Wax production
- Eardrum perforation
- Middle ear effusion
- Nasopharyngeal tumours blocking the Eustachian tube
- Otosclerosis
pysiology of presbycusis
o Progressive loss of hair cells in the cochlea
o Start losing higher frequencies first as outer hair cells are most exposed to damage
sensorineural causes of hearing loss
presbycusis sudden (idiopathic) hearing loss - thought to be ischaemia or viral noise exposure ototoxicity with drugs acoustic tumour dysacusis inflammatory diseases - measles, mumps, meningitis, syphilis, chronic middle ear infection perilymph fistula
what decibels require protection against
> 90
dysacusis
despite having normal hearing, some patients are unable to hear well in noisy environemnts
presumed due to a choclear abnormality
ototoxic drugs
aminoglycosides e.g. gentamicin
loop diuretics
spironolactone
aspirin
character of tinnitus
Ringing, hissing or buzzing sounds suggest an inner ear or central cause.
Popping or clicking suggests an external or middle ear cause or the palate
subjective vs objective tinnitus
Subjective if the sound can only be heard by the affected individual. Most commonly caused by things causing sensorineural hearing loss e.g. presbycusis. Ototoxic drugs cause bilateral tinnitus with associated hearing loss.
Objective if the sound can also be heard by the examiner. This is rare and occurs due to rare things, like rare vascular disorders, carotid pathology, or in high output cardiac states.
subjective unilateral tinnitus and sensorineural hearing loss
Meniere’s disease - episodes of tinnitus associated with hearing loss + vertigo lasting 15 mins –>24 hours
acoustic neruoma - especially if associated with unilateral hearing loss
subjective bilateral tinnitus and sensorineural hearing loss
age-related hearing loss
noise-induced hearing loss
drug-induced ototoxicity (aspirin, NSAIDs, Abx, loop diuretics, cytotoxic drugs)
subjective unilatearl or bilateral tinnitus and conductive hearing loss
impacted wax, otitis media, cholesteatoma
otosclerosis - especially if there is a family hisotry
secondary causes of tinnitus
secondary to head or neck injury, multiple sclerosis, diabetes, or thyroid disease
acoustic neruoma
a benign intracranial tumour
are misnomers as they most commonly arise from the vestibular nerve Schwann cells - a schwannoma
symptoms of acoustic neuroma
progressive ipsilateral tinnitus +/- sensorineural deafness (cochlear nerve compression)
dizziness
any patient presenting with unilateral tinnitus = acoustic neuroma until proven otherwise
other: large tumours might give unilateral cerebellar signs or raised ICP signs. balance problems and unsteadiness. if compresses trigeminal nerve then may cause a numb face or tingling
management options for tinnitus
Try having continuous, low-level, unobtrusive sound in the background
Hearing aids. If hearing loss >35Db, a hearing aid that improves perception of background noise makes tinnitus less apparent.
Psychological support
CBT
Relaxation techniques may also be useful
diagnosis of acoustic neuroma
audiogram - will show a sensorinureal pattern of hearing loss
MRI
treatment of acoustic neuroma
observation if there is no tumour growth
focused radiation (stereotactic radiotherapy) or surgery
vertigo define
vertigo is a symptom - it is the illusion of movement of the patient’s surroundings, typically rotatory
vertigo is always worsened by dizziness
associated symptoms: o Difficulty walking or standing (pt may even fall) o Nystagmus – principle sign o Relief on lying or sitting still o Nausea/vomiting/pallor/sweating
2 divisions of causes of vertigo
peripheral/vestibular - i.e. affecting the vestibular nerve or semi-circular canals
central - rare. affecting the visual-vestibular centres of the brainstem e.g. infarct or drugs. acoustic neuroma could be a central cause
benign paroxysmal vertigo (BPPV) symptoms
most common cause of peripheral vertigo
attacks of sudden rotational vertigo >30 seconds that is provoked by head turning
nausea is often associated
cause of benign paroxysmal vertigo (BPPV)
Most cases are primary/idiopathic:
canalolithiasis (canalith particles)
debris in the semi-circular canal which are disturbed by head movements, resettles and causes vertigo for a few seconds after the movement
or can be secondary to head trauma, viral labyrinthitis, Meniere’s disease, migraine, ear surgery
diagnosis of benign paroxysmal positional vertigo
nystagmus when performing the Dix-Hallpike manoevre is diagnostic
turn head to side. patients are lowered quickly to a supine position with the neck extended around 30 degrees below horizontal (hanging off the bed) - will experience vertigo and see nystagmus
treatment of benign paroxysmal positional vertigo
epley manoervures
- clears the debris form the semi-circular canals
generally is self- limiting and treatment is only necessary if persistant
Meniere’s disease symptoms and definition
dilation of the endolymphatic spaces by hydrops (excess fluid) - causes distension and rupture of Reissner’s membrane –> release of endolymph into perilymphatic space and causes injury to the sensory and neural elements of the inner ear
typically one ear affected but over time both
causing recurrent attakcs of vertigo lasting >20 mins +/- episodes of N+V
flutuating sensorineural loss and tinnitus
associated fullness of the ear
epidemiology of Meniere’s disease
can affect any age
40s and 50s more likely to experience it
considered to be chronic
acute labyrinthitis vs vestibular neuronitis
o Vestibular neuronitis is thought to be due to inflammation of the vestibular nerve and often occurs after a viral infection.
o Labyrinthitis is a different diagnosis that involves inflammation of the labyrinth.
Hearing loss is a feature of labyrinthitis, but hearing is not affected in vestibular neuronitis
5 vestibular causes of vertigo
benign paroxysmal positional vertigo - seconds -minutes
meniere’s disease - 30 mins - 30 hours
acute labyrinthisis or vestibular neuronitis - 30h-week
trauma
ototoxicty by aminoglycosides or loop diuretics
cholesteatoma
a destructive and expanding growth consisting of keratinizing sqamous epithelium in the middle ear and/or mastoid process
the keratinizing epithelium exhibits independent growth leading to expansion and resporption of underlying bone
are not classified as tumours or cancers
symptoms of cholesteatoma
foul smelling discharge may have conductive hearing loss tinnitus may be present headache pain
- facial paralysis and vertigo indicate central CNS complications.
management of vestibular neuronitis / acute labyrinthitis
o Reassure the person that symptoms will usually settle over several weeks – even if no treatment is given
o Advise that factors such as alcohol, tiredness, or intercurrent illness may have a greater than usual effect on their balance
o Advise that bed rest may be necessary but that activity should be resumed as soon as possible (even if vertigo becomes more prominent during movement).
o Advise the person not to drive when they are dizzy, or if they are likely to experience an episode of vertigo while driving.
o the person should inform their employer if their vertigo poses a risk in the workplace
o offer person written information
o if symptoms are severe, offer short-term symptomatic drug treatment
vestibular suppressant medications (for example antihistamines and antiemetics)