ENT/Opth Flashcards
what is a positive Rinne’s test and what does it imply?
when air conduction is louder than bone conduction.
either normal hearing or sensorineural hearing loss.
what is a negative Rinne’s test and what does it imply?
when bone conduction louder than air conduction - suggests conductive hearing loss.
(can get false +ve where the other ear is hearing the sound)
how do you interpret the findings of Weber’s test?
localises to contralateral ear in sensorineural hearing loss, but to the affected ear if conductive.
may localise to midline if bilateral sensorineural hearing loss!
what is otitis externa/how does it present?
severe pain, debris in ear canal ± swelling O/E
due to acute inflammation of skin of the meatus - diffuse infection (bacterial, viral or fungal) of skin of ear canal
what causes otitis externa?
excessive canal moisture
also - trauma (e.g. from fingernails), high humidity, absence of wax (from self-cleaning), narrow ear canal, hearing aids
what organisms commonly cause otitis externa?
pseudomonas most common
also - Staph aureus
explain the differences between mild, moderate and severe OE
mild - scaly skin, with some erythema. normal diameter of external auditory canal (EAC).
mod. - painful ear, narrowed EAC, smelly creamy discharge
severe - EAC occluded
how do you manage mild vs moderate vs severe OE?
mild - cleaning the EAC (e.g. gentle syringing, dry mopping, microsuction)
mod. - swab for micro, clean canal. topical abx ± steroid drops.
severe - insert thin ear wick with aluminium acetate, then after a few days meatus will open up enough for microsuction/cleaning
what should you be concerned about if a pt has OE resistant to treatment / persistent unilateral OE?
resistant to rx - could be SCC, do biopsy.
if persistent in diabetics/immunosuppressed/elderly - risk is of malignant/necrotizing OE
what is malignant/necrotizing OE? what causes it? management?
aggressive infection of external ear that can lead to temporal bone destruction and skull base osteomyelitis.
causes - 90% have diabetes. pseudomonus aeruginosa main cause (also Proteus, Klebsiella).
Rx - surgical debridement, systemic abx, specific immunoglobulins.
what is barotrauma, how does it present? management?
if Eustachian tube occluded, middle ear pressure can’t be equalised in diving/aircraft descent, causing damage.
Symps - severe pain, then secondary effusion (either transudate or haemotympanum).
Rx - supportive.
what is TMJ dysfunction? how does it present?
temperomandibular joint dysfunction.
symps - earache, facial pain, joint clicking/popping (on teeth grinding, join derangement, or stress)
signs - joint tenderness exacerbated by lateral movement of open jaw, or trigger points in pterygoid muscles.
can be a biopsychosocial thing and become a chronic pain syndrome!
how is TMJ dysfunction managed?
reassure/explain. simple analgesia.
specialist therapy - dental occlusion therapy, physio, CBT etc
name some causes of referred ear pain, classified by nerve affected
arises from diseases in areas around the nerves supplying the ear:
- V: auriculotemporal nerve (branch of trigeminal), can refer pain from dental disease, TMJ dysfunction
- VII: sensory brance of facial nerve refers pain in geniculate herpes (Ramsay Hunt)
- IX + X: tympanic branch of glossopharyngeal nerve + auricular branch of vagus can refer pain from posterior 1/3 tongue, pyriform fossa or larynx, or from the throat (e.g. tonsillitis, quinsy) - can cause otalgia post-tonsillectomy
- C2,3: great auricular nerve refers pain from soft tissue injury in neck + from cervical spondylosis/arthritis
briefly describe the physiology of hearing
1) sound waves are transmitted to the fluid filled cochlea via the external auditory canal, tympanic membrane and bony ossicles.
2) hair cells in basilar membrane of cochlea then detect vibrations and transduce them into nerve impulses
3) these impulses pass via the cochlear nerve (division of CNVIII) to the choclear nucleus in brainstem, then to the superior olivary nuclei
what is the function of the vestibular nerve?
carries information from the semicircular canals about balance
name the 3 bony ossicles of the ear
stapes
incus
malleus
briefly describe the anatomy of the middle ear
three bony ossicles are attached to tympanic membrane. the semicircular canals are filled with fluid, involved in balance sensation.
the tympanic cavity of the middle air is usually filled with air, communicating with mastoid air cells superiorly and the nasopharynx via the Eustachian tube
what is the function of the Eustachian tube?
it’s a pressure-equalizing valve for the middle ear, opens for a fraction of a second in response to swallowing or yawning
what is conductive hearing loss? what would Rinne’s/Weber’s show?
hearing loss due to problems with the outer or middle ear
Rinne negative
Weber - localises to affected side
what is sensorineural hearing loss? what would Rinne’s/Weber’s show?
hearing loss due to problems with the inner ear, cohclea or cochlear nerve
Rinne positive
Weber - localises to normal side
list some causes of conductive hearing loss
- congenital: atresia
- external auditory canal: wax, foreign body, otitis externa, chronic suppuration
- ear drum: perforation/trauma
- middle ear: otosclerosis, disorder of ossicles, otitis media
list some causes of sensorineural hearing loss
- end organ: advancing age, occupation acoustic trauma, Meniere’s disease, drugs (gentamycin, furosemide)
- CN VIII lesions: acoustic neuroma, cranial trauma, inflammatory lesions (e.g. TB meningitis, sarcoidosis, neurosyphilis, carcinomatous meningitis)
- brainstem lesions (rare): MS, infarction
describe the structure/function of the “vestibular apparatus” of the inner ear
two components - semicircular canals (rotational movements) and the otoliths (urticle and saccule - sense linear acceleration)
provide info to brainstem (via vestibular division of CN VIII) and cerebellum re static head position + turning of head