Surgical Specialties - ENT: ear. Flashcards
Otological causes of imbalance?
- Middle ear disease.
- Trauma involving labyrinth, stapedectomy, temporal bone fracture etc.
- Meniere’s disease.
- Labyrinthitis.
- Otosclerosis.
- Syphilis.
- Ototoxic drugs e.g. aminoglycosides.
- Acoustic neuroma.
- Impacted wax in eardrum.
- BPPV.
Episodes of vertigo + fluctuant hearing loss + aural fullness which are often preceded by tinnitus makes a diagnosis of what likely?
Meniere’s disease.
How might Meniere’s be treated?
- Reduce smoking, caffeine, salt.
- Betahistine (vasodilator) + diuretics to reduce endolymphatic fluid imbalance of inner ear.
- Surgery to drain endolymphatic sac (decompress inner ear) / vestibular neurectomy ( disconnect labyrinth) / labyrinthectomy ( destroy labyrinth).
Symptoms of labyrinthitis?
- Acute onset of vertigo.
- Nystagmus.
- Hearing loss (if cochlear involvement).
- Patient feels v unwell for first 24 hours with improvement after central compensation.
Failure of both labyrinths will cause?
- Bobbling oscillopsia (world shakes up & down when walking due to loss of normal eye control).
What is likely to be the cause of imbalance in children?
Otitis media with effusion i.e. glue ear.
Symptoms / signs of acute otitis media?
- Imbalance / vertigo.
- Otalgia (severe in children).
- Congested, bulging eardrum +/- rupture with bloody discharge.
- Systemic illness e.g. tachycardia, fever.
What is presbyacusis?
Progressive loss of hair cells in cochlea associated with ageing.
From which age is presbyacusis typically clinically noticeable?
60-65 y/o.
How might perforations from simple chronic otitis media without mastoid disease be treated?
- Tympanoplasty using a graft from temporalis fascia.
How are traumatic perforations of the tympanic membrane treated?
- Typically heal spontaneously so long as the ear is kept dry.
In adults who present with middle ear effusions investigations should be carried out to rule out what?
- Sinusitis.
- Nasopharyngeal tumours blocking eustachian tube.
What structures make up the external ear?
- Pinna.
- External auditory meatus.
- Tympanic membrane.
The eardrum is divided into which structures?
- Pars tensa.
- Pars flaccida.
What is the main landmark of the eardrum?
- Malleus handle.
Describe the middle ear.
Air filled space connecting nasopharynx to eustahian tube.
Function of the middle ear.
Transfers sound energy from air to the fluid medium in the cochlea.
The middle ear space - including mastoid air cells - is closely related to which structures?
- Temporal lobe.
- Cerebellum.
- Jugular bulb.
- Labyrinth of inner ear.
The middle ear contains how many ossicles? Name them.
Three.
- Stapes.
- Malleus.
- Incus.
What is the function of the ossicles?
Transmit sound vibrations from eardrum to cochlea.
What traverses the middle ear before exiting the skull?
Facial nerve.
What is contained within the inner ear?
Dense bony capsule containing a labyrinth forming the:
- Cochlea.
- Vestibule.
- Semicircular canals.
The membranous part of the inner ear is surrounded externally by?
Perilymph.
How is the inner ear sealed off from the middle ear?
By the stapes footplate and round window membrane.
The membranous part of the inner ear contains what?
Endolymph.
How is the cochlea connected to the brainstem?
By the auditory nerve.
How is sound perceived by the cerebral cortex?
- Displacement of basilar membrane and movement of hair cells > organised electrical discharge of vestibulocochlear nerve > sound perceived by cortex.
What comprises the peripheral balance organ?
- Vestibule + semi circular canals.
What is the important function of the peripheral balance organ i.e. the vestibule and semi circular canals?
- Connect to cerebellum and eyes.
- Important in maintaining posture and maintaining fixed eye position on head movement.
Conductive deafness arises as a result of?
- Disease affecting the outer or middle ear.
Sensorineural deafness arises as a result of?
Damage to the cochlea or vestibulocochlear nerve.
