Otology & Audiology

·         BULLOUS MYRINGITIS:

Pathognomonic for mycoplasma pneumonia infection

May occur in Ramsay Hunt syndrome

Viral and bacterial infections

·         "OTITIS MEDIA---CSOM ( CHRONIC SUPPURATIVE OTITIS MEDIA)---attico antral(dangerous type of ear), Schwartze op. done, csom with cholesteatoma with acute onset of vertigo-Rx-immediate exploration, Rx-cholesteatoma-radical mastoidectomy"

·         "ACOUSTIC NEUROMA---Auditory defect, sensory aphasia, changes in audiometry, commonly affects-8 Cr.N. & that too Superior Vestibular Nerve, early symp.-UniLateral hearing loss, it is most common (CPA) Cerebello-Pontine Angle tumours, Numbness of Face, Deafness, Internal Hydrocephalus, Ac.Nr. of 1 cm-IOC/diag.of choice=C.T. SCAN, hypoesthesia of the post. aspect of the ext. auditory canal-this is an early sign, "

·         "MENEIRE DISEASE / ENDOLYMPHATIC HYDROPS--- Ass.with Presbycusis, fes.--Tinnitus, Recurrent Vertigo, Deafness, Low Frequency SNHL/SND.-on pure tone Audiogram, GLYCEROL TEST is done in this, CODYTACK OPERATION is done, Cochlear type M.D.--Cochlear Deafness, Rx--Vasodilators--> increase Endolymph reabsorption, vasodilators of internal ear-is-Nicotinic acid,"

·         "OTOSCLEROSIS / OTOSPONGIOSIS ---A.D. more in Females, affects Oval window/stapes, ConductiveHearingLoss, colour of T.M.=FLAMINGO PINK, Paracusis willisii, Schwartz sign seen, Gelle's test -ve, Carhart's notch/ dip=2 khz, TOC=Stapedectomy with prostesis/Fluorides--cochlear otosclerosis,"

·         "OTITIS MEDIA---ASOM (ACUTE SUPPURATIVE OTITIS MEDIA) commonest cause--Pneumococcus -->very serious O.M., Pulsatile Otorrhea seen, 3yrs. Child with Fever, Ear ache, Congested T.M. with slight Bulge, it is the commonest cause of hearing loss?, Rx--Penicillin ( Myringotomy+ penicillin)

·         "TYMPANIC MEMBRANE---Blue Drum--seen in Secretory otitis media, nerve supply auriculotemporal nerve, T.M.-mobility--most mobile part-central, "----------((6))

·         "HEARING LOSS---SENSORENEURAL H.L.---(SNHL)--causes-old age, Cochlear Otosclerosis,Loud sound, Rx--COCHLEAR IMPLANT, Hydrops of Endolymphatic system-seen-in Alport's synd.,Usher's synd.,Pendred's synd.,"----------((5))

·         "MIDDLE EAR CAVITY---Nerve supply--Glossopharyngeal nerve,Floor--formed by INTERNAL JUGULAR BULB, In middle ear desease-there is - increased Threshold of AC & decreased BC (BC>AC), Resistance in middle ear-is-tested by IMPEDENCE Audiometry, Prominent Emenece over medial wall of midlle ear-is formed by-COCHLEA( BASAL TURNS),"----------((5))

·         "MYRINGOTOMY---done on POSTERO-INFERIOR Quadrant of T.M., commonest indication--Serous Otitis Media, a child with otitis media with Bulging T.M. with dull look, PUS in middle ear under tension,"-----------((4))

·         "GLUE EAR---8 yrs. Old child, Bilateral Conductive Deafness, seen in SECRETORY OTITIS MEDIA, or SEROUS OTITIS MEDIA---FLAT Tympanogram , "--------((4))

·         "MYRINGOPLASTY---Plastic Repair of T.M., note- initially audiometry done & then Sx done, or TYMPANOPLASTY---before T.plasty surgeon look for cochlear reserve, temporal fascia is used -it's metabolic rate is low, "-----------((4))

·         "BRAIN OTOGENIC ABSCESS---Mx-drainage of abscess followed by mastoidectomy, commonest site--temporal petrosal lobe, TEMPORAL LOBE ABSCESS---occurs in unsafe otitis media with high fever , convulsions "---------((3))

·         "ENDOLYMPH---most imp. Constituent-K+ , is seen in Scala Media , Drains into Virchow Robin Space,"-------((3))

·         "EUSTACHIAN TUBE---most common cause of E.T. disease--ADENOIDS, LENGTH=36mm( 3.6 cm),"-------((3))

·         "GLOMUS TUMOUR---in middle ear, Location--Hypotympanum, Pulsatile Tinnitus ,Pulsatile tumour in EAM which Bleeds to Touch,"---------((3))

·         "GRADENIGO'S SYND.---abducent VI Nr. Palsy, Retroorbital Pain, pain over face, Aural discharge/ otorrhoea, Pralysis of Ext./lat Rectus, Nr. Inv.= 5,6, GRADENIGO'S TRIAD---Mastoiditis, Petrositis, L R palsy,"--------((3))

·         "OTITIS EXTERNA---MALIGNANT--caused by P.Aeroginosa, common in D.M., & OLD age,"----------((3))

·         "RINNE'S TEST---+ve seen in presbycusis, -ve(BC>AC)-->middle ear disease,"--------((3))

·         "CSF RHINORRHOEA--- ant.cranial fossa fractures / Cribriform plate fracture , most imm. Rx-prophylactic antibiotics& x-ray, "-----------((3))

·         "STAPEDIAL MUSCLE---supplied by facial cr. Nerve, STAPEDIAL REFLEX---protective against loud sound , mediated by VII & VIII CR. N.,"---------((3))

·         "SUPRAMEATAL SPINE OF HENLE---landmark on lat.surface of temporal bone which acts as a guide to surgery to the antrum,"----------((3))

·         Donaldson line in vertigo surgery and mastoidectomy:  After performing a wide mastoidectomy, bone is removed from over the endolymphatic sac located in the posterior fossa dura just inferior to a line (Donaldson's line) drawn through the posterior semicircular canal where it is bisected by the horizontal semi- circular canal.

·         The Nylen-Bárány maneuver (reproducing the vertigo by having the patient go from a sitting to supine position while quickly turning the head to the side) will reproduce the vertigo of BPPV.

·         The cochlear aqueduct is a bony canal that connects the scala tympani (contains perilymph) to the subarachnoid space (contains cerebral spinal fluid). Like its counterpart, the vestibular aqueduct, the function of this aqueduct is not definitively known but is thought to be involved in fluid and pressure regulation of the bony labyrinth.

·         In the horizontal canal, displacement of the hair cell's steriocillia toward the vestibule (ampullopetal) increases the firing rate, whereas displacement away from the vestibule (ampullofugal) decreases the rate. The opposite situation exists in the posterior and superior canals.

·         As sound travels from air to a fluid medium, the final stimuli is greatly diminished because of impedance mismatching. The middle ear minimizes this problem, amplifying the sound energy by the area effect of the TM and the lever action of the ossicular chain. The effective vibrating area of the TM is about 17 times the area of the stapes footplate, resulting in a 17-fold increase in sound energy. The handle of the malleus is about 1.3 times the length of the short process of the incus, so the force at the stapes is increased by 1.3-fold. The combination of these two effects creates a 22:1 mechanical advantage, which provides a 25-dB increase in sound energy arriving to the cochlea.

·         An enlarged vestibular aqueduct (large vestibular aqueduct syndrome) predisposes to a neurosensory hearing loss and is associated with Pendred's syndrome and anatomic deficits of the cochlear modiolus.

·         OUTER HAIR CELLS

1.       Outer hair cells serve an amplifying role in the cochlea.

2.       They are responsible for the cochlear microphonic of electrocochleography recording.

3.       Generally, outer hair cells are more sensitive to trauma (noise exposure, ototoxicity) than inner hair cells.

·         Hearing is measured on a biologic scale in decibels hearing level (dB HL), whereas environmental sounds are measured on a physical scale in decibels sound pressure level (dB SPL).

·         A specific set of bisyllablic words, known as spondees, are presented to the patient at decreasing intensities. Spondees are two-syllable compound words that are pronounced with equal emphasis on each syllable-for example, oatmeal, popcorn, and shipwreck. The SRT is the lowest intensity at which the patient correctly identifies the word in 50% of the presentations. The SRT should be within ±7 dB of the three-frequency pure-tone average.

·         The acoustic reflex is measured with the immittance meter. The change in compliance of the middle ear is caused by contraction of the stapedial reflex and is time-locked to the presence of a loud acoustic stimulus. The ipsilateral reflex is measured with the stimulus is presented through a sealed probe. The contralateral reflex is measured through a probe on the opposite ear of the stimulus. Measurement of the acoustic reflex is a valuable technique that is used to determine the integrity of the neural pathways. It is also used to detect eighth nerve tumors, sensory cell impairment of the cochlea, and loudness tolerance for patients with SNHL.

·         The air-bone gap represents a response discrepancy between air- and bone-conducted stimuli and is indicative of CHL.

·         A "maximal" CHL can result in a 60-dB deficit. Ossicular discontinuity should be considered with losses > 50 dB.

·         CHARACTERISTICS OF CHOLESTEATOMAS

1.       Benign collection of squamous epithelium and keratin debris in the middle ear

2.       Present with history of recurrent ear infections

3.       May have a "trail sign" of debris along the canal to the perforation

4.       Cause CHL from mass effect and erosion/discontinuity of ossicles

5.       Treated surgically with removal of debris and infected air cells

·         Gunfire produces 140-170 dB of noise. An audiogram typically documents a hearing loss in the 4000-Hz range. A right-handed rifle or shotgun shooter tends to sustain a left-sided hearing loss, since the right ear is semiprotected by being tucked to the shoulder while the rifle is aimed and fired.

·         A temporary threshold shift is the transient hair cell dysfunction that occurs in patients who have been exposed to excessive noise. Repeated temporary threshold shift may result in a permanent hearing loss.

·         Deaf, with a capital "D," refers to a group of people who identify themselves as a cultural and linguistic minority. They are members of the Deaf community; they share a culture and manual language. The word Deaf has symbolic connotations and carries with it cultural information.

With a small "d," deaf refers to a pathologic condition or audiologic loss, and deaf people are not categorically members of the Deaf community.

Hearing impaired is a new term that was thought to be more politically correct and sophisticated. Hearing people made it up. It does not provide necessary cultural information.

American Sign Language (ASL) is the language of communication used by the Deaf community in the United States.

·         CIs are currently indicated for patients at least 12 months of age who have binaural severe to profound SNHL with intact eighth cranial nerve function and show little or no benefit from hearing aids.

Cochlear malformations are not a contraindication for CI, but modification of conventional implantation is necessary.

·         In the embryo, the first branchial arch gives rise to the first three hillocks that form the tragus, the helical crus, and the helix. The second arch gives rise to the second three hillocks that form the antihelix, the scapha, and the lobule.

·         Keratosis obturans is a disorder of unknown etiology seen mostly in young and middle-aged patients where excessive buildup of keratinizing squamous epithelium forms in the medial aspect of the external auditory canal. This buildup of debris blocks the canal, causing a full sensation in the ear that can manifest as conductive hearing loss. When the mass of keratinized epithelium is removed, the underlying skin appears shiny, atrophic, and erythematous. Treatment involves frequent debridement to avoid a large buildup that can be difficult and painful to remove.

·         Prussak's space is a pouch found posterior to the pars flaccida. It is bounded by the pars flaccida laterally and the neck of the malleus medially, and it is limited superiorly by the lateral mallear fold and inferiorly by the lateral process of the malleus. Retraction pockets or perforations of the tympanic membrane over this area may lead to the formation of a cholesteatoma. From this area, cholesteatomas may spread into the antrum and into the mastoid.

·         AD designates the right ear, AS the left ear, and AU both ears.

·         COMMON CAUSES OF DIZZINESS BASED ON SPELL DURATION

1.       Seconds: benign paroxysmal positioning vertigo

2.       Minutes: transient ischemic attack

3.       Hours: Ménière's disease

4.       Days: viral neurolabyrinthitis

5.       Variable: migraine

·         THE FIVE GENERAL CATEGORIES OF NYSTAGMUS

1. Gaze-evoked: direction changes with gaze to right, left, up, or down; not present with eyes centered
2. Positional: brought out when the patient is supine; persists indefinitely in certain head positions
3. Positioning: occurs transiently when the patient is abruptly moved (the Dix-Hallpike maneuver)
4. Spontaneous: evident when the patient is upright, worsens with gaze in fast-phase direction
5. Induced: elicited by stimulation with caloric or rotational tests

·         HOW TO DIFFERENTIATE ACUTE POSTERIOR FOSSA STROKE FROM ACUTE PERIPHERAL VESTIBULOPATHY

1. Walk the patient: stroke patients often cannot stand or walk unsupported.
2. Turn the lights down: constricted pupil due to Horner's syndrome may appear ipsilateral to the stroke.
3. Use the side of a tuning fork to check sensation to cold on the face and extremities: strokes may show sensory loss for temperature on the ipsilateral face and contralateral extremities.
4. Check for dysdiadochokinesia: it will affect the ipsilateral hand after a cerebellar stroke.
5. Unilateral deafness can occur ipsilateral to a stroke and does not prove the origin of vertigo is peripheral.

·         After a boat trip, healthy persons will feel a rocking sensation for several hours after disembarkation, called mal de debarquement. When this symptom persists for weeks, months, or years after the exposure to motion, it is called persistent mal de debarquement. Usually the results of the neuro-otologic examination and caloric tests are normal, and no new symptoms develop over time. The condition can resolve spontaneously and is resistant to treatment. There is an association with migraine, and some patients respond to migraine prophylactic medications or to vestibular rehabilitation. A similar rocking vertigo can occur without prior exposure to boat travel; the course and treatment of this syndrome are similar.

·         A cholesterol granuloma is a reactive mass that occurs after hemorrhage into petrous apex air cells. On CT, a punched-out bony lesion is present with an isodense mass that exhibits rim enhancement with intravenous contrast. The lesion is hyperintense on T1 and T2 MRI images, whereas cholesteatomas and mucoceles are hypointense on T1 and hyperintense on T2. Cholesterol granulomas are treated with procedures to drain the lesion to other aerated portions of the temporal bone. An infralabyrinthine approach to the petrous apex is most commonly used to drain this lesion.

·         The jugular foramen syndrome, also termed Vernet's syndrome, is paralysis of the cranial nerves that exit this canal: cranial nerves IX, X, and XI. The hypoglossal nerve exits through the hypoglossal canal and is thus unaffected. The most common culprit lesions include paraganglioma, schwannomas, meningiomas, metastatic lesions, and jugular vein thrombosis.

·         Sulzberger's Powder is a nonspecific antiseptic consisting of 2 gm iodine and boric acid powdered to make 100 gm. This powder is blown into the radical mastoid cavity to help keep it clean and dry after the debris and secretions have been cleaned away.