ear anatomy

Question 1

outer ear
middle ear
inner ear

Answer 1

outer ear: pinna

middle ear extends from tympanic membrane to lateral wall of the inner ear. transmits vibration from the tympanic membrane to the inner ear via the auditory ossicles

inner ear: houses the vestibulocochlear organs. converts mechanical signals to electrical. detects position and motion.

Question 2

bony labyrinth

membranous laybrinth

Answer 2

bony: cochlea, vestibule, three semi circular canals. lined internally with periosteum and perilymph,

membranous labyrinth: cochlear duct, semi circular ducts, utricle, saccule. contains endolymph.

Question 3

ear innervation

Answer 3

The inner ear is innervated by thevestibulocochlear nerve (CN VIII). It enters the inner ear via the internal acoustic meatus, where it divides into thevestibular nerve(responsible for balance) and thecochlear nerve(responsible for hearing):

Vestibular nerve– enlarges to formthevestibular ganglion, which then splits into superior and inferior parts to supply the utricle, saccule and three semi-circular ducts.

Cochlear nerve– enters at the base of the modiolus and its branches pass through the lamina to supply the receptors of the Organ of Corti.

Thefacial nerve, CN VII, also passes through the inner ear, but does not innervate any of the structures present.

Question 4

foreign body in ear.

Answer 4

unilateral thick purulent discharge
children
can cause a 2’ OE

removal performed under microscopic control
GA if a young child

if insect- ear drop with alcoholic base to kill insect then remove.

Question 5

otitis externa

swimmer’s ear

Answer 5

infection of the external ear
erythematous, swollen, tender, warm
debris and discharge accumulation

pseudomonas aeurginosa
s. epidermis
s. aureus
anaerobes
fungal- aspergillus

frequent water contact and humid environments
immunocompromised

tx: prevention, aural toileting, topical antibiotics, simple analgesia. flucloxacillin.

Question 6

surfers ear- exostosis

Answer 6

benign bony growths of the external auditory canal which interferes with normal wax migration. leads to occlusion and conductive hearing loss.

history of cold water swimming
single and unilatral

tx: surgical excision.

Question 7

Ramsay hunt syndrome

Answer 7

infectionof the geniculate gangnlino of the facial nerve with the herpes zoster virus

dizziness
sensory neural hearin gloss
LMN facial paralysis
loss of taste over 2/3 tongue

tx: antiviral, ENT emergency

Question 8

Otitis media

Answer 8

children- sever pain, inflammation of the tympanic membrane.
systemic features- fever, malaise

bacterial infection

Ix: otoscopy, test and document faical nerve

Tx: spontaenous resolve within 24 hrs. -3 days.

simple analgesics

Oral antibioticscan be considered in cases of:
Systemically unwell childrennot requiring admission
Known risk factorsfor complications, such as congenital heart disease or immunosuppression
Unwell for 4 days or morewithout improvement, with clinical features consistent with acute otitis media
Dischargefrom the ear (ensure swabs are taken prior to commencing antibiotic therapy)
Childrenyounger than 2 yearswithbilateral infections
Systemically unwell adult, provided not septic and with no signs of complications

amoxicillin

Question 9

mastoiditis

Answer 9

complication of AOM
inflammation within the air cells. can progress to necrosis, subperiosteal abssess.

boggy, erythematous swelling behind the ear. can push the pinna forward.

tx: IV abx, CT head if no improvement after 24hrs of IV abx.

higher risk of intracranial spread.

Question 10

OME with effusion (glue ear)

Answer 10

viscus inflammatory fluid in the middle ear.
conductive hearing impairment
chronic inflammatory changes and eustachian tube dysfunction

tx: 50% will resolve in 3 months (active surveillence)
if no resolution- hearing aid insertion or myringotomy and grommet insertion.

Question 11

cholesteatoma

Answer 11

pocket of ectopic keratinised stratifed squamous epithelium within teh middle ear

epithelial cells naturaly shed within the pockets but ca’t escape the middle ear sot the colleciton grows.

conductive hearing loss
hx of COM

pearly, keratinised or wax mass in the attic region

tx: surgery
ossicles can b reconstructed.

Question 12

otosclerosis pathophysiology

Answer 12

disorder of the dense otic capsule bone which houses the inner ear. formation of new bone in the region of the footplate of the stapes. restricted mobility of the foot plate which causes conductive hearing loss.

if this spreads to the cochlea then can cause mixed hearing loss.

Autosominal dominant mode of inheritance.

Question 13

otosclerosis symptoms

Answer 13

gradual worsening hearing loss
O/E normal ear canal and ear drum
if active otosclerosis reddish hue can be seen in the tympanic membrane.

increased vascularity over the medial wall of the middle ear.

• tinnitus
• unsteadiness

Question 14

otosclerosis management

Answer 14

hearing aid

surgery- stapedectomy

Question 15

labyrinthitis

Answer 15

inflammation of the vestibular labyrinth
acute onset of vertigo, nausea, vomiting

systemic or viral like illness

supperative or bacterial is rare (meningitis)

Question 16

BPPV

Answer 16

a sudden attack of vertigo occurs which change in head position or body posture. few seconds then resolves spontaenously.

follows head injury or viral illness

commonest cause of vertigo
canalithiasis- free floating debris

diagnosis: Dix Hallpike test +ve and neuro-otological exam is normal
treatment: Epley manouver

Question 17

Menier’s disease

Answer 17

disorder of the inner ear
relatively rare
autoimmune disorder
accumilation of endolymphatic fluid

attacks of vertigo with nausea and vomiting. minutes-hours. hearing is mfufled, tinnitus, aural and ear fullness.

treatment:
restirction of salt in diet
vestibular sedatives (prochlorperazine) during an attack
histamine analogue- betahistine or thiazide diuretic

intratypmanic entamicin injections to destroy the vetibular labrinth

triad:
episodic vertigo, tinnitus, hearing loss.