Otology Flashcards
B/L progressive hearing loss in young female s/o….
Otosclerosis
Important points to remember in otosclerosis (3)
- Paracussis Willi-hear better in noisy environment.
- Worsen in pregnancy
- Positive Schwartz sign in early stages.
Otosclerosis is autosomal……..
Common in ……people
Dominant in 70% of cases
South Indians and white.
Site of predilection of otosclerosis
Mx site where otosclerosis present is ….
Globuli interossei
Normal temporal bone has embryonic cartilage tests which are called globuli interossei.
Fissula ante fenestrum- in front of oval window.
Pathogenesis of otosclerosis
Disease of bony labyrinth in which vascular spongy bone formation near the oval window —> fixation of foot plate of stapes.
Otosclerosis causes ……hearing loss. ( conductive / SNHL)
Paracussis Willi is also called ……
Conductive
Lombard effect
Systemic association with otosclerosis (2)
Van de Hoeve’s syndrome -otosclerosis with blue sclera
Pathological bone fractures - Paget’s disease
Rinne’s and webers test for otosclerosis
Tympanogram is ….
Feature seen in early coclear otosclerosis
Rinne’s- negative
Webers - lateralised to affected ear.
Type A
Cookie-bite curve
First sign in histopathology of otosclerosis is …..
Blue mantle- change in extracellular staining —followed by otospongiosis—finally otosclerosis
Rx for otosclerosis
If Schwartz sign positive : per oral Na fluoride.
If Schwartz sign -ve: stapes piston prosthesis - stapedectomy.
45 year old female with pulsatile tinnitus and bleeding ear mass s/o….
Glomus jugulare/glomus tympanicum
2 vascular tumors of ENT
- Young male : juvenile angiofibroma
- Young female: glomus jugulare.
Both are benign, highly vascularised tumors.
Glomus Tumor is also known as …..(2)
Chemodectomas
Non chrommafin paragangliomas.
Embryonal structure of glomus jugulare
Derieved from neural crest cells that migrate with sympathetic autonomic ganglia to form paraganglia.
Glomus tumors are also found in …..(4)
In glomus Tumor of temporal bone, they are …..
Adrenal and extra adrenal systems
Carotid body
Vagus nerve
Non chromaffin
2 sites that glomus tumor arise in temporal bone:
- Glomus jugulare: Arise from some of jugular bulb( below floor of middle ear)
- Glomus tympanicum: Promontory of middle ear.
Mx site for glomus tumor in middle ear is ….
Main blood supply of glomus tumor is ….
Hypotympanum
Ascending pharyngeal artery
Histological feature of glomus tumor
Glomus Tumor mc occur on ….side
Cluster of chief cells- zellbellen.
Left side
Mc used classification for glomus tumor is ….
Glasscock jackson and fisch
What is rule of 10’s in glomus jugulare?
10% familial
10% multi centric
10% functional - secret catecholamines
Signs of glomus tumors: (4)
- Rising sun sign: Tumor arises from flow of middle ear .
- Browns/ pulsation sign: When pressure applied to EAC, mass blanches.
- Red drum: pulsatile reddish brown Tumor behind intact TM.
- Aquino sign: observation of decreased pulsation with carotid compression.
Difference between vernet and villaret syndrome
Syndromes of glomus Tumor:
Vernet: paresis of CN 9,10,11 + complaints of hoarseness, dysphagia, dysarthria: shoulder weakness.
Villaret syndrome: compression of cervical sympathetic ganglion—> Horners syndrome.
MRI findings of glomus tumor:
Best technique for glomus tumor is ….
Salt and pepper appearance on T1 and T2 images.
CT with MRI+ DTPA enhancement.
What is phelp sign?
Glomus Tumor eroding the caroticojugular spine.
Glomus jugular erodes the bony partition between jugular fossa and hypotympanum.
Where does glomus tympanicum occupy?
Middle ear with preservation of bony partition.
Glomus Tumor is postive on …..
Prerequisite for glomus tumors (2)
Octreotide scintigraphy
- Arteriography before resection of large tumor
- Screening for catecholamines
…..should NEVER be done for glomus tumor
Rx for glomus tumors (4)
Biopsy -highly vascular tumor
- Surgical resection
- Embolization
- Radiotherapy
- HStereotactic - gamma knife radiosurgery.
Mx cranial nerve involves in glomus tumor is ….
Complications of glomus tumor. (4)
Facial nerve
- Hearing loss- conductive hypoglossal nerve palsy.
- Facial nerve palsy
- I/L Horner syndrome
- Jugular foramen syndrome
Long standing h/o foul smelling ear discharge
Blood stained foul smelling ear discharge
Unsafe CSOM
Primary acquired cholesteatoma
Long standing h/o foul smelling ear discharge with vertigo
Mc site for labrynthine fistula is …
Unsafe CSOM with labrynthine fistula.
Lateral Semicircular canals
Define CSOM
Mx organism
Long standing infection of part/ whole middle ear cleft
Pseudomonas aeruginosa
Chronically draining ear that fails to respond to antibiotics . Dx
Cholesteatoma
Hallmark of unsafe CSOM . Define
Primary acquired cholesteatoma
White pulpy mass on upper part of TM in pars flaccida secondary to retraction pockets.
Difference between safe and unsafe CSOM.
Safe CSOM: tubotympanic
1. Copious discharge, odorless, intermittent , mucoid
2. Granulations are absent
3. Central perforation
4. Polps are pale
5. Cholesteatoma absent.
6. Intracranial complication not seen.
7. Rx: conservative —>myringoplasty
Unsafe CSOM: atticoantral/ tympanomastoid.
1. Continous purulent d/c with scanty foul smelling d/c
2. Attic per formation
3. Granulations and cholesteatoma present
4. Red fleshy polyps
5. Intracranial complications seen.
6. Rx: conservative - ear drops,systemic ab—> fails —> modified radical mastoidectomy
Round window shielding effect seen in ….
Define
Tubotympanic disease
Paradoxic effect - hear better in present of discharge than when ear is dry.
Ossicular necrosis in CSOM seen in ….
Pathology of atticoantral CSOM (4)
Long process of incus
- Cholesteatoma
2 Ossicular necrosis - Cholesterol granuloma - dark blue/black TM
- Osteitis and granulation tissue.
Lining of middle ear cleft (3)
Anterior and inferior part: ciliated columnar epithelium
- Middle part: cuboidal epithelium
- Attic : pavement like epithelium.
Define cholesteatoma
Skin in the wrong place.
Keratinizing squamous epithelium in middle ear or mastoid
Cholesteatoma is seen in…. It is a …..
Mx csite of origin of cholesteatoma is ….
Sclerotic mastoid
Epidermal inclusion cyst
Posterior epitympanum
Define congenital cholesteatoma
Sites of congenital cholesteatoma (3)
Embryonic epidermal cells that rest in the middle ear cleft.
Middle ear
Petrous apex
Cerebellopontine angle
In primary acquired cholesteatoma, there is not previous …….(3)
Otitis media
Pre-existing performation
Otorrhoea
What is the retraction pocket theory?
Wittmaack’s theory:
ET obstruction—> negative pressure in middle ear cavity —> formation of retraction pocket in attic region—> accumulation of desquamated epithelium —> pressure necrosis of TM—>cholesteatoma.
Ruedel and Landt theory of primary cholesteatoma-
Wendt and sade’s theory
Basal cell hyperplasia
Squamous metaplasia
Where is secondary acquired cholesteatoma seen?
How does this occur?
Pre-existing perforation of pars tensa of TM.
There is pre-existing infection- migration of squamous epithelium from EAC to middle ear to TM.
Long standing h/o foul smelling discharge with headache, vomiting and convulsions s/o….
Mx site is …..
Otogenic brain abscess-intracranial complication.
Temporal lobe.
Otogenic brain abscess in adults is due to:
In children due to …..
Adults: CSOM
Children: Acute otitis media
Investigation of choice for Otogenic brain abscess.
Rx: (5)
CT scan
Rx:
1. Parenteral ab
2. Dexamethasone
3. Iv mannitol to decrease ICT
4. Neurosurgical drainage of abscess
5. Rx associated ear disease also.
What is otitic hydrocephalus?
Increased ICT but normal CSF finding
Persistent ear discharge in spite of modified radical mastoidectomy is…
Define Gradiengo syndrome
Petrositis - infection of petrous part of temporal bone.
GERD:
Ear discharge
Retroorbital pain- CSF involvement
Diplopia- CN 5,6.
Deep temporal headache is also seen
6 year old child with mouth breathing and hearing loss s/o….
Causes of OME.
Glue ear- secretory OM/ OME
Eustachian tube blockage secondary to :
Nasopharyngeal carcinoma: adults
Adenoid hypertrophy : children
—> fluid collection in middle ear.
Sms of secretary OM (3)
Hearing loss leading to inattentive behavior and turn up volume of TV
Fullness of ear
Minimal/ low ear pain
Otoscope finding of glue ear
Gold standard for dx glue ear
Decrease mobility of TM
Fluid level or air bubbles behind TM
Pneumatic otoscopy
Audiometry shows ……hearing loss for OME.
Impedance audiometry shows …..curve
Xray shows ……
Conductive hearing loss
B type curve
Clouded mastoid hair cells
Medical rx for glue ear :(2)
Systemic antibiotics
Nasal decongestants
Surgical rx for OME
Myringotomy —> no improve—> grommet tube in the Anteroinferior quadrant
Management for traumatic perforation of TM
Conservative management-keep ear dry
No ear drops
They spontaneously heal.
External ear consists of …….(3)
Pinna
EAC
Tympanic membrane
Pinna has …… structure, absent in …..
Lateral surface in external ear similar to …….
Single yellow elastic cartilage
Lobule
Fingerprints
What is boxer ear?
Complication is ……
Hematoma when it strips the pericondrium from the cartilage—> cartilage necrosis.
Post trauma deformity-> cauliflower ear
Where is incisura terminalis? Clinical importance
Area between crus of helix and tragus.
Importance: useful for endoaural approach as it doesn’t cut through cartilage.
Extrinsic muscles of Pinna are supplied by ……
Arterial supply for Pinna
Facial nerve
Posterior auricular- superior auricular branch of external carotid artery.
Nerve supply of Pinna:
Posterior superior: great auricular nerve
Posterior: CN 7& 10.
Medial side: Auriculotemporal br of manidibular division of CN5
EAC develops from ……
Length in adult :……
Dorsal part of first brachial cleft/ groove.
24mm.
Parts of EAC
Furuncles form commonly in …..part
Cartilaginous 1/3= 8mm
Body-2/3= 16mm
Cartilaginous part- as it contains hair follicles, sebaccous, ceruminous glands
Importance of fissure of santorini
Through which infection from parotid of superficial mastoid infection enter EAC
Foreign body lodgement site jn EAC is …
Importance of foramen of Huschke
Isthmus of bony canal.
Defiency in Anteroinferior part of bony canal in children upto 4 years of age- infection to and from parotid.
Blood supply to EAC
Nerve supply of EAC
External carotid artery
Anterior and roof: Auriculotemporal nerve
Posterior and floor: auricular branch of cn10. ( Arnold nerve)
Interesting phenomenon of Arnold nerve
- Vasovagal reflex:
While cleaning of EAC —> patient develops coughing, bradycardia ,syncope and cardiac arrest. - Appetite: coz of vagal innervation.
What is hitzelberger sign?
Hypoesthesia of posterior meatal wall seen in case of facial nerve injury.
Tympanic membrane is …..at birth. Adult it is….
Total surface area….
Horizontal
Angle is 55 degrees.
85 sqmm
Vibrating area : 55sqmm
Layers of tympanic membrane. (3)
Importance of the layers
Outer: Epithelial: ectoderm
Middle: fibrous : mesoderm
Inner: mucosal: endoderm
When tympanic membrane heals; it does so by 2 layers.
First squamous epithelium closes it—> fibrous cartilage develop
Vibrating surface of tympanic membrane is known as …..
What is most reliable landmark in otoscopy?
Pars tensa.
Umbo- point of max inward convexity of TM.
Where is cone of light?
Pars flaccida is called…..
Locates internally by ……nerve
Anteroinferior quadrant
Sharpnell membrane
Facial nerve
Main blood supply of TM
Maxillary artery- deep auricular branch and anterior tympanic branch.
Nerve supply of TM
Outer surface:
Anteroinferior : Auriculotemporal n
Posterosuperior: greater auricular nerve
Inner surface : Jacobson’s nerve: cn9
Multiple perforations in TM is s/o …..
Multiple blebs/ hemorrhagic blebs s/o…
Tuberculosis
Bullous myringitis
Hemorrhagic blebs s/o:
Granulation tissue s/o:
Myingotomy incision is made in ….quadrant.
Barotrauma
Granular myringitis
Posteroinferior / anteroinferior quadrant
Middle ear cleft consist of ….(3)
Tympanic cavity- middle ear
Eustachian tube
Mastoid cell system.
Anatomic division of tympanic cavity
Mesotympanum
Epitympanum
Hypotympanum
Narrowest part of tympanic membrane
Widest part of tympanic membrane
Prussak space lies in …..
Mesotympanum
Epitympanum
Epitympanum
Pouch of von troeltsch lies in …..
Contents of Mesotympanum (5)
Mesotympanum
Handle of malleus
Long process of incus
Round window
Oval window
Tensor tympani and chorda tympani nerve
Contents of epitympanum/attic (2)
Head and neck of malleolus
Body and short process of incus
Contents of Hypotympanum
Contains pro tympanum.
Middle ear portion around ET opening.
Compartment in epitympanum seen on CT
Anterior tympanic recess or supratubal recess.
Roof of middle ear formed by ….
Floor is formed by …
Lateral wall is formed by …..
Anterior wall contains …..
Thin tegmen tympani
Pars tementalis
Tympanic membrane
Eustachian tube orifice
What is promontory?
Contains of middle wall of TM
Bulge in the middle ear formed by basal area of cochlea.
Promontory
Oval window
Round window
Facial nerve
Horizontal lateral SCC
PORN- Horizontal
Anterior if oval window contains book like projection called ….
Importance .
Processes cochlearformis for tendon of tensor tympani.
Processes cochlearformis marks level of genu of facial nerve- imp landmark for surgery of facial nerve.
What is the pyramid?
Fossa incudis contains ….
Bony projection in posterior wall which contains stapedius muscle.
Short process of incus
Auditory ossicles derieved from ……
Malleus and incus: 1st arch
Stapes: 2nd arch
Footplate of stapes, annular ligament:
Otic capsule
Most lateral bone of ossicles
Largest bone of ossicles
Footplate of stapes held on the oval window by ….
Malleus
Incus
Annular ligament.
Inculomalleolar joint is …..
Inculostapedial joint is ……
Labyrinth joint is …….
Saddle joint
Ball and socket joint
Syndesmotic joint
Function of ossicles
Conduct sound from TM to oval window and then inner ear fluid.
Tensor tympani develops from ……, supplied by ………
Stapedius develops from ……supplied by …..
1st arch , Mandibular nerve
2nd arch , nerve to stapedius br of facial n
What is mastoid antrum? Mastoid develops from …..&…..bone
Air sinus in petrous temporal bone
Squamous and petrous bone
Types of mastoid antrum.
Pneumatized: 80%
Sclerotic: 20%
Mixed: diploeic
Pneumatization begins at ….yr, complete by …..yr
Boundaries of mastoid antrum
1 yr, complete by 4-5 yrs age
Roof: tegmen tympani
Lateral wall: squamous part of temporal bone.
Medial wall: petrous bone
Posterior wall and floor: mastoid bone
Anteriorly: communicates with attic through aditus ad antrum.
Landmark of mastoid antrum is …..
Importance of korner’s septum.
Mac ewen’s triangle- suprameatal triangle
Surgically important as it may cause difficulty in locating antrum and deeper cells.
Mastoid antrum can’t be reached unless koener’s septum has been removed.
Thus if not removed, persistence of disease even after mastoidectomy.
Importance of Eustachian tube
Normal length of ET
Connects tympanic cavity with nasopharynx. Helps equalise pressure on both sides of TM
36mm: lateral 1/3: 12mm - bony
medial 2/3: 24mm - fibrocartilaginous
Muscles of ET (2)
- Tensor palati
- Levator palati
Gerlach tonsil are ……
Importance of ostmann pad of fat?
Lymphoid tissue of ET
Keeps the ET closed and prevents reflux of Np secretion into middle ear.
Chorda tympani location in middle ear
Travels in between malleus and incus
2 bony spicules in medial wall of middle ear:
- Ponticulus: from promontory to pyramid
- Subiculum: separates oval window and round window.
Inner ear contains ….&…..
Development of inner ear.
Bony labrynth and membranous labrynth.
Pars superior:
SCC : anterior, posterior and lateral. and utricle
Pars inferior : saccule and cochlea
Bony labrynth filled with …..
Includes….
Perilymph- rich in sodium ~ECF
Includes: cochlea, vestibule, semicircular canals.
Bony cochlea is …..long
Winds…..times around…..
Spiral lamina is divided into…..
Spiral lamina attaches to…..
32mm long.
2 3/4 turns around central axis -modiolus
Upper scala vestibuli
Lower scala tympani
Basilar membrane
Apex of cochlea called ……
If cochlea has only 1 1/2 turns; deformity is called ….Rx.
Helicotrema
Mondini’s dysplasia of cochlea
Cochlear implants
Basal turn of cochlea is towards…..side
Basal turn senses …..
Apex senses …..
Oval window side
High frequency sound
Low frequency sound
Fn of utricle and saccule and SCC
Utricle and saccule: linear balance
SCC : angular balance
Infection like meningitis and gain access to inner ear through….
Cochlear aqueduct.
Scala tympani is connected to subarachnoid space through cochlear aqueduct.
Membranous labrynth is filled with ….contains ….(3)
Endolymph- rich in K+
Contains:
Cochlear duct: within cochlea
Utricle and saccule: within vestibule
Semicircular ducts.
Cochlea inner structure contains ..(3)
……is responsible for endymph
Separation of scala vestibuli and Scala media is by …..
Scala vestibuli
Scala media - basilar membrane-organ of corti
Scala tympani
Stria vascularis
Reissner’s membrane
Arterial supply of cochlea is from ….
Venous drainage is into ….
Labyrinthine artery- arises from anteroinferior cerebellar artery
Inferior petrosal sinus
Lateral venous sinus
Nerve supply to inner ear…
Blood supply to inner ear is ….of blood supply to middle ear.
Superior and inferior vestibular nerves
Independent
Scala tympani opens into ….
Difference between perilymph and endolymph
Round window
Perilymph:
extracellular fluid, rich in Na ions
Communicates CSF via cerebral aqueduct
Space between bony and membranous labrynth.
Endolymph:
Space in membranous labrynth
Rich in K+ ions
Secreted by secretary cells of stria vascularis of cochlea.
Surgical landmark for endolymphatic sac is ….
Perilymph in ….&….
Endolymph in ….
Donaldson’s line
Perilymph: Scala vestibuli
Scala tympani
Endolymph: Scala media
Scala communis is….
Structures of the ear fully formed at birth. (4)
Where Scalia vestibuli joins with Scala tympani at the helicotrema
Middle ear
Ossicles
Labyrinth
Cochlea
How is the tympanic membrane protected while swimming
Mastoid tip develops at ….age
Eddie currents
2 years
Organ of corti is filled with ….
Infection of middle ear to subarachnoid space in infants is through….
Corticolymph
Hyrtle’s fissure
Most common part of residual cholesteatoma after mastoid surgery is ….
Inner ear is developed from….
Sinus tympanicum
Neuroectoderm
Internal auditory canal is point of entry of ….
What is bill’s bar?
Cranial nerve 7&8
Bony septum in upper part of internal bony canal
Dorello’s canal is entry of …..nerve
Tonsillitis can cause ear pain via ….
Referrred ear pain through cn5 are: (4)
Cn6
Cn9
Dental disease
TM joint
Oral cavity
Sphenopalatine
Cervical spondylosis has referred ear through …..
Bell’s palsy causes referred ear pain through …..
C2,C3 nerve
Cn7
Costen syndrome causes ….
Dental malocclusion—> TMJ dysfunction—>referred ear pain.
Anotia is …..
Microtia is …..
Surgical reconstruction of pinna is done at ….year age using ….
No pinna
Small pinna
6 year age using costal cartilage
Membranous labyrinth is derived from ….
Bony labyrinth is derived from …..
Cochlea develops by ……weeks of gestation.
Surface ectoderm
Mesenchyme
20th week
What is bat ear?
Rx,
What is Darwin tubercle?
Absence of antihelix .
Otoplasty by age 6
Anatomical variation- conical elevation on helix.
Bulge on flow of mastoid air cavity is ….
Importance.
Lateral SCC
Landmark for 2nd genu of facial nerve
Importance of first genu.
Landmark for processes cochlearformis-house of geniculate ganglion.
What is Bell’s palsy?
Idiopathic, sudden onset ,U/L sudden onset facial nerve palsy.
Forehead muscles are also affected.
Angle of mouth deviated to normal side.
Ear: hyperaccusis- loss of stapedius reflex.
Etiology of Bell’s palsy.
Edema in labrynthine segment of facial nerve which is the narrowest segment of facial nerve—> compression.
Rx for Bell’s palsy
- Oral CS x 3 weeks
- If pt comes within 3 days- acyclovir
- If no recovery even after 3 weeks:
Electrophysiological nerve testing to assess degeneration of facial nerve.
Define :
1. Presbycussis:
2. Diplacussis
3. Hyperaccusis
4. Paracussis
- Age related SNHL
- Meniers disease
- Bell’s palsy
- Otosclerosis
Site of lesion of Ramsay hunt syndrome at ….
Ramsay hunt syndrome caused by ….
Geniculate ganglion at 1st genu of cn7
Reactivation of VZV
C/f of Ramsay Hunt Syndrome
- Vesicles in external ear
- LMN paralysis
- Loss of taste
Rx for Ramsay Hunt syndrome
Facial recovery is….
Acyclovir + steroid
50% cases only.
What is Melkerson Rosenthal Syndrome? (3)
Recurrent facial nerve palsy
Fissured tongue
Swelling of lips.
What is the auditory pathway ?
ECOLIMA
Eight cranial nerve
Cochlear nucleus
Olivary complex superior
Lateral Leminiscus
Inferior colliculus
Medial Geniculate body
Auditory cortex - lies on superior temporal gyrus.
Where does decussion happen?
Cross over of information from right hemisphere to left
At olivary nucleus.
Difference between inner and outer hair cells
Inner:
Total number :3500
Doesn’t get damaged
Develops earlier
Flask shaped
Has only one row
Generation of OAE: no
Outer hair cells:
Contains 12000
Contains 3-4 rows
Cylindrical shaped
Can generate OAE
Mainly efferent fibers
Can get damaged by ototoxic drugs and high noise .
Importance of tectorial membrane
Gelatinous matrix that overlies organ of corti.
The shearing force between hair cells and tectoral membrane provides stimulus to hair cells.
How does presbycusis happen?
With age, basal hair cells are lost more than apex- thus they lose high frequency sound.
Direction of sound is differentiated by ….
Utricle determine ….
Saccule determine …..
Inferior colliculus
Horizontal linear acceleration
Vertical linear acceleration
Utricle and saccule contain …
Otolith membrane- which contains calcium carbonate crystals -otoliths
Vestibular nerve is called …..ganglion
Posterior SCC is supplied by …nerve
Lateral SCC is supplied by ….nerve
Scarpa’s ganglion
Inferior vestibular nerve
Superior vestibular nerve
Motion sickness in spacecraft is due to …..
Semicircular canals- coriolis effect
Etiology of BPPV.
For unknown reasons ( h/o trauma, ear infection maybe present) - otoliths from gelatinous membrane enter SCC-posterior SCC- cause BPPV.
Dx of BPPV
RX.
Dx: Dix Hallpike Maneuver
Rx: Epley maneuver - particle repositioning maneuver.
Pathophysiology of superior canal dehiscence syndrome
Unfortunately another window is created in SCC, so sound can’t properly pass through when in inner ear—> conductive HL .
This is called third window effect.
SCDs also called ….
Auditory sms of SCDs
Great otologic mimicker
Auditory sms:
1. Conductive HL
2 Hearing their eyes move
3. Hearing their own voice (conductive hyperaccusis)
4. Pulsatile tinnitus
Vestibular sms of SCDs (3)
Noise induced vertigo-tullios phenomenon
Pressure induced vertigo- hennebert’s sign
Valsalva inducing vertigo.
Dx and rx of SCDs
Dx: multi slice CT scan of temporal bone
Rx: surgery
60 year old with blood stained ear dicharge, earache and facial palsy
It’s due to ….
Malignant otitis externa
Infection of underlying bone
Mx org of malignant OE
Mc involved nerve is …..at ….
First scan to order in this patient
Follow up scan is ….
Pseudomonas
Facial nerve at skull base- osteomyelitis
Tc bone scan
Gallium bone scan
DOC for malignant OE
3rd gen cephalosporin + AG
What is otoacoustic emissions?
Importance. (2)
When sound given to cochlea—> record the sound coming from outer hair cells of the cornea to EAC.
Importance:
1. distinguish cochlea from retrococlear hearing loss.
Cochlea: OAE : absent
Retrocochlear: OAE: present
- Screening test for neonates and mentally challenged people.
Cn 8 pathology- OAE ?
Normal- as OAE detects sound from cochlear portion by movement of outer hair cells.
Electrococleography measures …..
Test is useful for dx of ….
Earliest evoked potential in the cochlear and auditory nerve within 5 msec.
Menier’s disease
What is BERA? aka….
What does it do? How many waves does it have? Most important one…
Brainstem evoked response audiometry
Auditory brain stem response.
Sound from the ear—> record activity of impulse from brain stem.
It has 7 waves- most important is wave 5, as it is produced by lateral leminiscus.
Screening for neonates:
Screening for high risk hearing:
OAE
BERA:
High risk hearing: LBW, meningitis
ABR is recorded earliest at …..wks gestation
27-28 weeks
Indications of BERA/ABR (7)
- Best for detection of deafness in difficult to test cases.
- For assessment of nature of deafness( CHL, SNHL)
- Identification of site of lesion- retrocochlear pathologies
- To asses maturity of CNS in newborns
- To assess brain death
- To dx brainstem pathology (eg: MM, pontine tumor)
- For intraoperative monitoring
Types of BERA waves
Wave 1: distal part of cn 8
Wave 2: proximal part of cn8
Wave 3: cochlear nucleus.
Wave 4: superior olivary nucleus
Wave 5: lateral leminiscus
Wave 6-7: inferior colliculus
What is vestibular evoked myogenic potential?
Absent / diminished VEMP: (4)
VEMP.
Sound given to utricle and saccule—> recorded from tonically contracted SCM.
Absent VEMP:
1. Ménière’s disease
2. Vestibular Neuronitis
3. Vestibular / acoustic schawannoma
4. BPPV
VEMP positive in (2)
- Perilymph fistula
- SCDS- Superior Canal dehiscence syndrome
Indication of cochlear implant
Parts of cochlear implant components
Profound SNHL (>90db) with normal cn 8.
External:
1. Microphone
2. Speech processor
3. Transmitter
4. Battery .
Internal component : via scala tympani to round window.
Outcomes of cochlear implant
- Children and young adults- post lingual deafness for short duration.
- If implanted early, even children with prelingual deafness can be treated
Indication of ABI (3)
Where is ABI placed?
Auditory brain stem implant :
1. NF 2- b/l vestibular / acoustic neuromas
2. Congenital aplasia of cn8
3. Michelle’s aplastic of cochlea.
Lateral recess of 4th ventricle
What is BAHA?
Principle of BAHA
Bone anchoring hearing aid
Sound is conducted directly to cochlea via bone conduction and eliminates EAC,middle ear.
Parts of BAHA
- Titanium screw- implanted into skull
- Sound precessor
- Titanium abutment-connects the sound processor to the screw.
Indications of BAHA (4)
- Anotia with hearing loss
- EAC atresia
- Chronic discharging ear
- Unilateral severe SNHL.
Use of microwick
For trans tympanic injection of medication into inner ear.
Audiogram is also known as…
It is a ……investigation. It is go see….
Value of normal audiogram
Pure tone audiometry
Subjective
Hearing threshold of the patient.
> 25db.( closer to zero, better the hearing )
Audiogram symbols
AC: O: right ear
X: left ear
BC: brackets
Also— red color: right ear, blue color: left ear.
AB gap is seen in …..
Both AC and BC are poor then…
Upper line is always ….
CHL
SNHL
Bone conduction
How is mixed HL?
2 dips seen in audio grams are:
AC and BC poor with AB gap
Otosclerosis: 2000 Hz in BC - CHL
SNHL: 4000Hz in AC and BC -boiler’s notch
Noise deafness.
Audiometry features of presbycusis and meniers disease
Presbycusis:
B/L , high frequency hearing loss
At base of cochlea
Sloping curve seen in audiogram.
Ménière’s disease:
U/L, low frequency hearing loss
At the apex of the cochlea
Rising sun is seen in audio gram.
Impendence audiometer has …..curves
What are the types?
5 curves
Type A: Normal
Type B: flat: glue ear
Type C: negative side:
ETD, retraction pocket
As: otosclerosis
Ad: ossicular dislocation
Indications for myringotomy
Acute suppurative otitis media: posteroinferior
Serous otitis media with grommet insertion: anteroinferior quadrant.
Myringotomy define
Myringoplasty define
Myringotomy: incision of TM to drain middle ear.
Myringoplasty: treat the rupture of TM defect in pars tensa.
Mc graft used for myringoplasty
Define tympanoplasty
Temporalis fascia
Ossicular reconstruction with or without myringoplasty—> eradication of disease from middle ear along with repair.
Cortical mastoidectomy is known as ….
Indication (2)
Simple mastoidectomy/ schwartz operation.
Indication:
1. Acute coalescent mastoiditis
2. Incompletely resolved otitis media with positive reservoir sign. -meatus fills up with pus as soon as it’s mopped out.
Define radical mastoidectomy.
Indication: (2)
Whole mucosa of middle ear, remnants of TM and ossicles except stapes are removed.
- Malignancy of external and middle ear
- Unresectable cholesteatoma
Rex of choice for atticoantral disease
Most common site of injury is …
Modified radical mastoidectomy.
Facial nerve in second genu.
Difference between canal wall up and canal wall down mastoidectomy
Canal wall up: posterior wall is preserved
Canal wall down: posterior wall is removed.
Egs of canal wall down procedure
Radical mastoidectomy
Modified radical mastoidectomy
Bondy operation
Recurrence of residual cholesteatoma in canal wall up and canal wall down procedure
What about swimming?
Hearing aid fitting?
Canal wall up: high
Canal wall down: low
Canal wall up: allowed
Canal wall down: discouraged
Canal wall up: easy
Canal wall down: problematic
What is lateral sinus thrombosis?
Picket fence fever- chills and rigors and in between pt is totally fine!!
Due to periodic release of hemolytic streptococci induced bacteremia in blood.
What is griesinger sign?
Tender part of internal jugular vein and mastoid region- due to extension of thrombosis.
What is Tobey Ayer test?
Used for lateral sinus thrombosis.
When a LP needle into spinal cord, and manometer on it, pressure is measured for the IJV.
If thrombosis on one side, the csf pressure will be shown higher on the manometer.