w3 Flashcards
what is otosclerosis?
A metabolic bone disease of ossicles & otic capsule
fixation of ossicles (stapes)
- Spongy bony growth occurs and then solidifies
what hearing loss does otosclerosis cause?
conductive or mixed hearing loss or cochlear
what is cochlear otosclerosis
hen boney growth degrades into cochlea and the loss is purely sensorineural
Clinical otosclerosis:
symptomatic and presenting with combination of hearing loss and tinnitus (rarely vertigo)
Histological otosclerosis
Asymptomatic more common than clinical, typically diagnosed postmortem
classification:site of lesion
- Which structure is affected (less used because clinicians see subtypes as a continuum rather than 2 distinct entities)
Fenestral otosclerosis
stapes predominately affected
retrofenestral otosclerosis
cochlea predominantly affected
Prevalence otosclerosis
Caucasian 10%, Asian 5% African American 1% native American 0%
onset of otosclerosis
15-45 years
clinical sex ratio otosclerosis
M:F 1:2.5
histological sex ratio otosclerosis
1:1
Hereditary otosclerosis
family history 8 genes implicated
Endocrine Otosclerosis
increase prevalence in women
Autoimmune otosclerosis
immune system genes found associated with otosclerosis
metabolic otosclerosis
genes in bone remodeling pathway found associated (not causative) with otosclerosis
Osteosclerotic process
resorption and formation of new bone
early phase otosclerosis
otospongiosis: vascular spongy bone growth
late phase otosclerosis
dense sclerotic bone in areas of earlier resorption & otospongiosis
Cochlear dysfunction otosclerosis
invade membranous labyrinth
Atrophy of spiral ligament in lateral wall
site of dysfunction (stapes & otic capsule)
Middle ear (conductive component): bone remodeling of oval window & foot plate(anterior focus, most common; round window less frequent
Cochlea: sensorineural component (otosclerosis)
- Perilabyrinthine decalcification
- Osteosclerotic bone of otic capsule
for otosclerosis with SNHL (cochlea) Damage occurs via
(1) bony invasion of membranous labyrinth (2) enzymes produced in osteosclerotic foci adjacent to lateral wall of cochlea, infiltrate membranous labyrinth
- Disrupts cochlear fluid homeostasis
- Eventual degeneration of organ of corti
case history and symptoms otosclerosis
Progressive HL: conductive, mixed, Sensorineural, Carhart notch
- Initially unilateral but often progress to bilateral (80%)
- Tinnitus common (75%)
- Vestibular complaints (25%)
medical diagnosis otosclerosis
based on case history, symptoms and audiological assessment
- Physical exam limited, most patients have normal EAC and TM
- Schwartze sign: reddish hue around TM due to highly vascularized otoscpongeosis and can sometimes be visualized through the TM
- Imaging not usually required: high res CT used for surgical planning
Audiogram otosclerosis
variable presentation
- Unilateral initial, progress to bilateral
Common presentation: conductive HL in low freq
- With progression configuration flattens
- further progression=decline in BC threshold in high freq &
increased conductive component in low freq
carharts notch otosclerosis
- 2KHz Carhart notch (not always present)
- Primary resonance of the ossicular chain for BC signals approx.. 1.7KHz
- Otosclerosis causes reduction in BC activated ossicular motion affecting resonance notch appears at 2KHz
immitance otosclerosis
Type A or As
Acoustic reflexes absent or unusual (reverse or “on-off” or diphasic)
interventions for otosclerosis
Stapedectomy, stapedotomy
Medical treatments: floride (not effective) or Bisosphonate (vary range of success)
Amplifications: for those not wanting/fit for surgery
Cochlear implant: advanced otosclerosis invading cochlea causing SNHL
Stapedectomy:
older traditional technique where entire footplate removed, prosthetic piston used to replace entire stapes
Stapedotomy
more common, footplate remains intact, less trauma to oval window, less possibility of damaging inner ear, incus vibroplasty
goal of otosclerosis surgery
close air bone gap
- Otosclerosis can recur and cause displacement of prosthesis
- Revision surgery may be required
- May not restore hearing to initial post-op level
what are Temporal bone paragangliomas
(Aka glomus tumours)
Neuroendocrine glomus cells cluster to form paraganglia in parasympathetic nervous system
- Clusters reside in adventitia (connective tissues) of blood vessels and parasympathetic nerves
where are Temporal bone paragangliomas distributed
ear, larynx, along vagus nerve & associated with carotid artery & aorta
4 types of head and neck glomus tumours
Carotid body paragangliomas (CBP)
Glomus jugulare (GP)- occur within temporal bone
Glomus tympanicum (GT)
Glomus vagale (GV)
age for temporal bone paraganglioma
40-60 years
temporal bone paraganglioma sex related assocition
4:1 ratio of females to males
temporal bone paraganglioma etiology
- Sporadic
- Genetic: Familial autosomal dominant disorder (<10% cases; chromosome 11q23)
Glomus tympanicum (GT) originate
from promontory in ME
a. Course of tympanic branch of glossopharyngeal nerve (Jacobsen’s nerve
Glomus jugulare originate
Arise in area of jugular bulb below the floor of the ME
a. Aurical branch of the vagus nerve (Arnold’s nerve) or Jacobsen’s nerve
b. May compress cranial nerves IX and XII
c. Additional growth can lead to compression of the brainstem
glossopharyngeal and vagus nerves affect
swallowing and horse voice
hypoglossal nerve affect
loss of sensation & paralysis of tongue
symptoms glomus tumour
Vary with tumor origin and spread
Earliest signs: hearing loss and pulsatile tinnitus
Additional symptoms: headache, vertigo, otalgia, aural fullness, cranial nerve compression etc.,
role of audiologist in glomus tumour detection
aware of unilateral symptoms associated with vestibular schwannoma (acoustic neuroma) and need for referral
- Glomus tumours associated with similar symptoms/complains but different clinical presentation
- Aware of potential comorbidities of these tumours
pathology of glomus tumour
- Firm red mass, slow growing, typically benign, non metastazing
- Locally destructive: multi-directional spread along paths of least resistance, erode mastoid bone, invade ME, eustachian tube, brain cavity, cochlea and vestibular end organs, rupture TM
Glomus jugulare incidence
paraganglioma 1-3/100 000 of which 16%-24% are Glomus jugulare
Glomus Tympancium incidence
paraganglioma 1-3/100 000 of which 20% are GT
GT can cause
conductive loss: impaired ossicular motion, abnormal ME pressure/aeration
- SNHL and/or dizziness: tumour can invade inner ear
Glomus Jugulotympanicum
For large tumours, site of origin may be uncertain as it involves:
- Jugular bulb & fossa
- ME promontory
Ex., tumour grows superior-laterally from jugular formen to invade ME
Medical examination for Paraganglioma
Otoscopy findings
Inspect oral cavity and pharynx for pulsing contractions
Pulsatile tinnitus: decreases with head rotation ipsilaterally
Neurological exam
Radiology: CT & MRI
Otoscopy findings for Paraganglioma
- Brown sign= red “blush” on TM; blanches with ear canal pressure
- Red mass behind TM (rising sun)
- Biopsy not advised on outpatient basis (bleeding)
Medical management GT:
surgical excision
- Tympanoplasty; Mastoidectomy if more extensive
Medical management GJ:
depends on tumour extent and patient factors
- Wait and see approach (patient risk factors: age, anaesthetic risk, tumour location)
- Surgical excision: challenging surgical procedure (ENT & neurosurgery) – risk of cranial nerve damage & excessive bleeding
- Radiation may be preferable
- Radiation & surgery may be combined
audiology assessment glomus tumour
- Conventional audiometric assessment
- Variable audiometric and immittance results
- Immittance: pulsatile admittance synced to heartbeat
- Referral for medical assessment if classic signs (pulsatile tinnitus, red mass noted on otoscopy)
audiology managment glomus tumour
- Monitoring for recovery post-treatment & recurrence
- Aural rehabilitation if residual hearing loss following medical management
aural rehabiliation glomus tumour
- Counselling for HL & tinnitus
- Conventional amplification & ALDs
- Cochlear implant
- Bone conduction aid
