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SECTION 1: TUNING FORK TESTS

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1. Absolute Bone Conduction (ABC) Test

• Purpose: Compares the patient's bone conduction (BC) with the examiner's BC to assess sensorineural hearing loss
• Tuning fork used: 512 Hz
• Method:
  • All air in the ear canal is excluded (meatus occluded)
  • The vibrating tuning fork is placed on the mastoid of the patient
  • When the patient no longer hears it, it is placed on the examiner's mastoid
  • If the examiner still hears it → ABC reduced → indicates cochlear/SNHL
  • If the examiner does not hear it → ABC normal
• Significance: Tests cochlear reserve directly
• Normal result: Patient and examiner hear for equal duration (ABC = normal)
• Abnormal result (ABC reduced): Sensorineural hearing loss on that side
• Used as a bedside test to differentiate CHL from SNHL

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2. Gelle's Test

• Purpose: Detects fixation of the stapes (as in otosclerosis)
• Tuning fork used: 512 Hz
• Method:
  • A Siegle's speculum (air-tight) is placed in the external canal
  • Vibrating tuning fork is placed on the mastoid
  • Air pressure is alternately increased and decreased using the pneumatic speculum
  • Observe for change in loudness
• Interpretation:
  • Normal (Gelle Positive): Increasing pressure → hearing diminishes; decreasing pressure → hearing improves (normal stapes mobility)
  • Abnormal (Gelle Negative): No change in hearing with pressure changes → stapes is fixed (as in otosclerosis)
• Key point: A negative Gelle's test is strongly suggestive of otosclerosis

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3. Weber's Test

• Purpose: Lateralization test to determine which ear has greater hearing loss
• Tuning fork: 512 Hz placed on the vertex (midline of forehead or vertex of skull)
• Interpretation:
  • Conductive Hearing Loss (CHL): Weber lateralizes to the affected (poorer) ear - because the masking noise from environment is eliminated
  • Sensorineural Hearing Loss (SNHL): Weber lateralizes to the better ear
  • Normal / Equal hearing: Sound heard in midline
• Key mnemonic: "CHL - same side; SNHL - opposite (better) side"
• Always used with Rinne's test for complete assessment

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4. Tuning Fork Tests (General Overview)

• 512 Hz is preferred - gives best results (balance between tactile vibration at low frequency and short duration at high frequency)
• False negative Rinne: In profound unilateral SNHL, BC > AC via transcranial transmission - test the opposite ear with a Barany noise box (masking)

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SECTION 2: PRESBYACUSIS

• Definition: Age-related bilateral progressive sensorineural hearing loss affecting high frequencies first
• Age group: >60 years; incidence increases with age
• Pathology (Schuknecht's Classification):
  1. Sensory type - Loss of outer hair cells at basal turn of cochlea; abrupt high frequency loss
  2. Neural type - Loss of spiral ganglion neurons; poor speech discrimination
  3. Strial (metabolic) type - Atrophy of stria vascularis; flat audiogram; best prognosis
  4. Mechanical (Cochlear conductive) type - Stiffening of basilar membrane; gradual slope audiogram
• Features:
  • Bilateral, symmetrical, gradual high-frequency SNHL
  • Tinnitus (high-pitched)
  • Diplacusis (distorted perception of sound)
  • Phonemic regression - speech discrimination worse than expected from pure tone thresholds
  • Recruitment present
• Audiogram: Gently sloping downward curve toward high frequencies
• Management:
  • Hearing aids (most important)
  • Cochlear implant in profound cases
  • Counseling, lip reading
  • No medical cure

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SECTION 3: OSTEOMEATAL COMPLEX (OMC)

• Definition: A functional unit in the lateral nasal wall in the middle meatus through which drainage of anterior group of sinuses occurs
• Components:
  • Uncinate process
  • Ethmoidal bulla
  • Hiatus semilunaris
  • Infundibulum
  • Ostia of maxillary, anterior ethmoid, and frontal sinuses
• Importance:
  • Any obstruction here (polyps, mucosal edema, anatomical variants) leads to recurrent sinusitis
  • Anatomical variants causing OMC obstruction: concha bullosa, paradoxical middle turbinate, Haller cell, deviated septum
• Clinical significance: Target of FESS (Functional Endoscopic Sinus Surgery)
  • FESS restores drainage via the OMC without disturbing normal mucosa

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SECTION 4: REFERRED OTALGIA

• Definition: Ear pain arising from distant sites due to shared nerve supply - the ear itself is normal
• Nerve supply of ear (sensory):
  • Auriculotemporal nerve (V3) - TMJ, lower teeth
  • Facial nerve (VII) - Geniculate ganglion
  • Glossopharyngeal (IX) - Tonsil, pharynx, tongue base
  • Vagus (X) - Larynx, hypopharynx, esophagus
  • Greater auricular nerve (C2, C3) - Cervical spine
• Common causes by nerve:

• Key point: Always examine throat, teeth, cervical spine when no local ear cause is found
• Most important cause to exclude: Malignancy of pharynx/larynx

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SECTION 5: PREAURICULAR SINUS

• Definition: A congenital pit/sinus anterior to the tragus and helix of the ear
• Embryology: Failure of fusion of the 6 hillocks of His (during development of the pinna in 6th week of fetal life)
• Location: Usually at the anterior margin of the ascending helix
• Lined by: Stratified squamous epithelium; contains desquamating material
• Inheritance: Autosomal dominant; bilateral in 25-50%
• Clinical features:
  • Usually asymptomatic
  • Intermittent discharge of whitish cheesy material
  • Recurrent abscess formation when infected
  • Tender swelling, redness, pain on infection
• Complications: Recurrent infection, abscess, fistula formation
• Management:
  • Asymptomatic: Observe
  • Infected: Antibiotics first, drain abscess if fluctuant
  • Definitive: Complete surgical excision of the entire sinus tract (recurrence if incomplete)
  • Must trace the entire sinus tract to the perichondrium

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SECTION 6: KERATOSIS OBTURANS

• Definition: Accumulation of desquamated keratin plugs in the EAC (bony part), leading to widening and erosion of the canal
• Etiology: Defective epithelial migration in the EAC; associated with sinusitis and bronchiectasis
• Pathology: Plug of keratin fills entire EAC; canal wall becomes smooth and widened
• Features:
  • Severe otalgia (main symptom)
  • Conductive hearing loss
  • Profuse foul-smelling discharge
  • Bilateral (50%)
  • Younger age group
  • Canal is widened and smooth on otoscopy
• Differentiate from EAC cholesteatoma:

• Management: Removal of keratin plug under GA + regular suction clearance; NOT surgery unless complications

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SECTION 7: OTOMYCOSIS

• Definition: Fungal infection of the external auditory canal
• Organisms:
  • Aspergillus niger (black spores - most common overall)
  • Aspergillus fumigatus (greenish)
  • Candida albicans (white, creamy)
• Predisposing factors: Humid climate, use of broad-spectrum antibiotics, immunosuppression, diabetes, swimming, topical steroids
• Features:
  • Intense pruritus (main complaint)
  • Mild to moderate hearing loss
  • Scanty discharge
  • Characteristic appearance: Black or greenish spore-bearing hyphae visible like "wet blotting paper" or fungal mat
  • Aspergillus: Black dots (conidia) on white or yellow background
  • Candida: White creamy discharge
• Diagnosis: Clinical + microscopy + culture
• Management:
  • Thorough aural toilet (suction cleaning)
  • Antifungal drops: Clotrimazole 1% solution (first choice), or nystatin
  • Boric acid in spirit (3%) - acidifies canal, inhibits fungal growth
  • Systemic antifungals (itraconazole) if severe/immunocompromised
  • Keep ear dry

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SECTION 8: MALIGNANT (NECROTIZING) OTITIS EXTERNA

• Definition: An aggressive, life-threatening infection of the EAC spreading to the skull base
• Causative organism: Pseudomonas aeruginosa (>95% cases)
• Predisposing factors:
  • Diabetes mellitus (most common - elderly diabetics)
  • Immunocompromised (HIV, chemotherapy, steroids)
  • Elderly patients
• Pathogenesis: Pseudomonas invades EAC → through fissures of Santorini → osteomyelitis of temporal bone → spreads to skull base
• Clinical features:
  • Severe, unrelenting otalgia (disproportionate to examination findings)
  • Purulent otorrhoea
  • Granulation tissue at bony-cartilaginous junction (pathognomonic)
  • Facial nerve palsy (most common cranial nerve involved - VII)
  • Progressive involvement: IX, X, XI (jugular foramen syndrome)
  • Low-grade fever
  • No response to conventional treatment
• Investigations:
  • ESR elevated
  • Gallium-67 scan - most sensitive for activity/monitoring
  • Technetium-99 bone scan - shows early bone involvement
  • CT scan - shows bone erosion, extent of disease
  • MRI - soft tissue extension
  • Culture: Pseudomonas aeruginosa
• Management:
  • Long-term anti-pseudomonal antibiotics (6-8 weeks minimum):
    • Ciprofloxacin (oral, high dose) - drug of choice
    • IV Piperacillin-tazobactam or ceftazidime for severe cases
  • Aural toilet and debridement
  • Strict diabetic control
  • Hyperbaric oxygen therapy (adjunct)
  • Surgery: limited role - only if medical treatment fails
• Mortality: High if untreated; cranial nerve involvement worsens prognosis

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SECTION 9: FURUNCULOSIS OF THE EAR

• Definition: Acute staphylococcal infection of a hair follicle in the cartilaginous (outer 1/3) EAC
• Organism: Staphylococcus aureus
• Note: Only cartilaginous EAC has hair follicles; bony EAC does NOT, so furuncle is limited to the outer third
• Clinical features:
  • Severe, throbbing otalgia - worse on chewing (TMJ movement), opening mouth, tragal pressure
  • Trismus (if severe)
  • Pain on pulling the pinna (differentiates from otitis media)
  • Narrowing/occlusion of EAC → conductive hearing loss
  • Regional lymphadenopathy (pre/post-auricular)
  • Systemically, not very toxic (unlike malignant OE)
• Otoscopy: Localized red swelling in outer EAC, single/multiple
• Management:
  • Conservative (early): Oral antibiotics (flucloxacillin/amoxiclav), NSAIDS, local heat
  • Incision and drainage once fluctuant (under LA)
  • Ribbon gauze soaked in 10% ichthyol glycerine in canal
  • Swab for culture and sensitivity
  • Treat underlying conditions (diabetes, eczema)

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SECTION 10: HEMATOMA AURIS

• Definition: Collection of blood between the perichondrium and auricular cartilage
• Cause: Direct blunt trauma to the pinna (common in wrestlers, rugby players - "Cauliflower ear")
• Pathology: Blood separates perichondrium from cartilage → cartilage loses blood supply → fibrosis and calcification
• Clinical features:
  • Smooth, fluctuant, painless swelling on the anterior surface of the pinna
  • Purple/bluish discoloration
  • Loss of normal auricular contours
• Complications: If untreated → organization → fibrosis → cauliflower ear (perichondritis, cartilage necrosis)
• Management:
  • Aspiration (early, within 24-48 hours) under strict asepsis
  • Incision and drainage if large/clotted
  • Pressure bandage (through-and-through sutures or bolster dressing) to prevent re-accumulation
  • Antibiotics to prevent perichondritis
  • Repeat aspiration if recurs; surgical drainage for organized hematoma

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SECTION 11: WAX (CERUMEN) IN EAR

• Definition: Accumulation of cerumen (wax) in the EAC causing symptoms
• Composition: Secretions of ceruminous glands + sebaceous glands + desquamated epithelium
• Types: Hard (dry), soft (wet), obstructive
• Clinical features:
  • Conductive hearing loss (sudden, often after bathing - wax swells)
  • Tinnitus, sense of fullness
  • Reflex cough (Arnold's reflex - vagal branch in EAC)
  • Otalgia (if impacted)
• Indications for removal: Symptomatic, impairs otoscopy, before audiometry
• Removal methods:
  1. Syringing (most common) - warm water at body temperature, directed at posterior wall; contraindicated if TM perforation, history of ear surgery, CSOM
  2. Aural toilet - using Jobson Horne probe with cotton wool
  3. Softening agents first - sodium bicarbonate drops, olive oil, cerumenolytic agents (3-5 days before syringing)
  4. Microsuction (safest method, used in perforated TM)

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SECTION 12: CALORIE TEST

• Definition: A test of vestibular function (horizontal semicircular canal and superior vestibular nerve)
• Principle: Thermal stimulation creates convection currents in the endolymph of the horizontal semicircular canal, generating nystagmus
• Procedure (Fitzgerald-Hallpike method):
  • Patient lies supine, head elevated 30° (brings horizontal SCC into vertical plane)
  • Irrigate each ear with:
    • Cold water (30°C) - COWS mnemonic: Cold Opposite
    • Warm water (44°C) - Warm Same side
  • Duration: 40 seconds; wait 5 minutes between tests
  • Normal: Nystagmus for 90-120 seconds
  • Canal paresis: Reduced/absent response on that side
  • Directional preponderance: Nystagmus greater in one direction
• Mnemonic: COWS - Cold Opposite, Warm Same (direction of fast phase of nystagmus)
• Clinical uses:
  • Assess vestibular function
  • Diagnose unilateral vestibular hypofunction
  • Evaluate Meniere's disease (reduced caloric response in affected ear)
  • Pre-cochlear implant assessment

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SECTION 13: GLUE EAR (Secretory Otitis Media / Otitis Media with Effusion)

• Definition: Accumulation of thick, viscous, mucoid fluid in the middle ear cleft without signs of acute inflammation
• Most common cause of CHL in children (peak age 2-5 years)
• Etiopathogenesis:
  • Eustachian tube dysfunction (most important)
  • Adenoid hypertrophy blocking ET orifice
  • Recurrent AOM, allergy, cleft palate
  • Impaired mucociliary clearance
  • Fluid becomes thick ("glue-like") due to goblet cell hyperplasia
• Clinical features:
  • Bilateral conductive hearing loss (20-40 dB)
  • Dull, retracted, amber or blue TM
  • Air-fluid level or bubbles behind TM
  • No pain (unlike ASOM)
  • Speech delay, inattention, poor school performance
• Investigations:
  • Tympanometry: Type B (flat) curve - most diagnostic
  • Audiometry: CHL
  • Otoscopy: dull, retracted TM
• Management:
  • Watchful waiting (3 months) - 50% resolve spontaneously
  • Autoinflation (Valsalva, Otovent balloon)
  • Treat adenoids
  • Grommets (ventilation tubes) - if persists >3 months with hearing loss ≥25 dB; restores hearing immediately
  • Adenoidectomy + grommet insertion (children >4 years)
  • Hearing aids if surgery not possible

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SECTION 14: ACUTE SUPPURATIVE OTITIS MEDIA (ASOM)

A. Stages of ASOM

B. Aetiopathogenesis

• Age: Most common in children 6 months - 2 years (horizontal ET, large adenoids)
• Route: Ascending infection via Eustachian tube (most common)
• Organisms:
  • Streptococcus pneumoniae (most common)
  • Haemophilus influenzae (2nd most common, especially non-typeable)
  • Moraxella catarrhalis
  • Staphylococcus aureus (post-perforation)
  • Group A Streptococcus
• Predisposing factors: URTI, adenoid hypertrophy, cleft palate, immunodeficiency, day care, bottle feeding

C. Clinical Features

• Otalgia - severe, throbbing, often wakes child at night
• Fever (high grade)
• Hearing loss (conductive)
• Otorrhea (mucopurulent) - once TM perforates, pain suddenly relieves
• In infants: ear tugging, irritability, poor feeding, vomiting
• Otoscopy: TM red, congested, bulging, loss of landmarks and light reflex

D. Management

Bulging TM (Stage 3-4): Active management required

• Analgesia: Paracetamol + ibuprofen
• Antibiotics (drug of choice): Amoxicillin (high dose: 80-90 mg/kg/day in 2-3 divided doses x 10 days)
  • Penicillin allergic: Azithromycin or Cefuroxime
  • Resistant cases: Amoxicillin-clavulanate
• Nasal decongestants: Xylometazoline drops (helps ET function)
• Myringotomy (paracetesis): Incision of TM
  • Indications: Bulging TM with severe pain, no response to antibiotics in 48 hrs, suppurative complications, immunocompromised, age < 6 months
  • Site: Anteroinferior quadrant of TM
• Follow-up at 6-8 weeks to ensure resolution

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SECTION 15: CHRONIC SUPPURATIVE OTITIS MEDIA (CSOM)

A. General (2015 LQ, 2004 LQ)

• Definition: Chronic inflammation of the middle ear and mastoid with persistent TM perforation and discharge for >6-12 weeks
• Two types:
  1. Tubotympanic (Safe/Benign) - central perforation, no cholesteatoma
  2. Atticoantral (Unsafe/Dangerous) - marginal/attic perforation, cholesteatoma

B. Tubotympanic (Safe) CSOM

• Organisms: Pseudomonas aeruginosa, Staphylococcus aureus, Proteus, E.coli
• Management:
  • Aural toilet (dry mopping/suction)
  • Topical antibiotics: Ciprofloxacin ear drops (drug of choice); avoid aminoglycosides if TM perforated
  • Treat upper respiratory infection
  • Myringoplasty (repair TM) once ear is dry for 3 months
  • Tympanoplasty if ossicular involvement

C. Atticoantral (Unsafe) CSOM / Cholesteatoma

• Key feature: CHOLESTEATOMA (keratinizing squamous epithelium in middle ear)
• Types of cholesteatoma:
  • Congenital (behind intact TM)
  • Acquired - Primary (pars flaccida retraction) or Secondary (epithelial invasion through marginal perforation)
• Perforation: Attic (Shrapnell's membrane) or posterior marginal
• Discharge: Scanty, foul-smelling (offensive odor due to bone erosion + infection)
• Features:
  • "No pain, no gain" is false here - painless until complications
  • Granulation tissue, polyp
  • Bony erosion of ossicles, tegmen, lateral sinus plate, facial canal
  • Hearing loss - CHL or mixed
• Investigations: HRCT temporal bone (shows soft tissue density, bone erosion)
• Management: SURGERY is mandatory (no conservative cure)
  • Atticotomy (limited disease)
  • Modified radical mastoidectomy (extensive disease)
  • Canal wall up (CWU) or Canal wall down (CWD) mastoidectomy

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SECTION 16: COMPLICATIONS OF CSOM

Extracranial Complications

Intracranial Complications

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Bezold's Abscess

• Definition: Abscess formed when pus from mastoiditis perforates the medial surface of the mastoid tip (inner cortex) and tracks along the sternocleidomastoid muscle
• Pathogenesis: Mastoid empyema → erosion of thin medial cortex of mastoid tip → pus under SCM → neck abscess
• Features:
  • Deep, tender neck swelling along the anterior border of SCM
  • Ear discharge, otalgia, fever
  • Head tilted toward affected side
  • Trismus if pterygoids involved
• Differentiate from Citelli's abscess: Bezold = along SCM; Citelli = posterior belly of digastric
• Management: Drainage + mastoidectomy + antibiotics

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SECTION 17: LATERAL SINUS THROMBOSIS

• Alternate name: Sigmoid sinus thrombophlebitis
• Pathogenesis: CSOM/cholesteatoma → erosion of bony plate over lateral (sigmoid) sinus → perisinus abscess → thrombophlebitis → thrombosis
• Clinical features:
  • "Picket-fence" (quotidian) spiking fever - classic
  • Rigors and sweating
  • Griesinger's sign - edema over mastoid emissary vein (pathognomonic)
  • Tobey-Ayer test - compression of ipsilateral IJV does NOT raise CSF pressure (due to thrombus)
  • Crowe-Beck test - compression of contralateral IJV raises CSF pressure normally
  • Headache, septicemia
  • Papilledema (raised ICP)
  • Septic emboli → septic pulmonary infarcts, meningitis
• Investigations:
  • MRI/MRV - gold standard (shows "empty delta sign" on MRI with contrast if superior sagittal sinus involved)
  • CT with contrast
  • Blood culture (positive for causative organism)
• Management:
  • Mastoidectomy to remove source
  • Antibiotics (IV, broad-spectrum - target Pseudomonas, Staph, anaerobes)
  • Anticoagulation (controversial but used in progressive cases)
  • Ligation of IJV (if septic emboli persist despite treatment)
  • Surgical drainage of perisinus abscess

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SECTION 18: OTOSCLEROSIS

A. Aetiopathogenesis

• Definition: Disorder of enchondral bone of otic capsule characterized by localized areas of abnormal bone remodeling
• Genetics: Autosomal dominant with 25-40% penetrance; family history in 25% cases
• Sex: Female > Male (2:1); worsens during pregnancy
• Age: 15-45 years (reproductive age group)
• Bilateral in 70-80% of cases
• Pathology:
  • Most common focus: Fissula ante fenestram (anterior to oval window)
  • Abnormal bone (otospongiosis) replaces normal endochondral bone → stapes footplate fixed
  • Result: Progressive conductive hearing loss
  • If spreads to cochlea (cochlear otosclerosis) → mixed or SNHL
• Possible triggers: Measles virus (controversial), fluoride, estrogen

B. Clinical Features

• Progressive bilateral CHL (usually starts in one ear)
• Age of onset: 2nd-3rd decade
• Paracusis Willisii: Hears better in noisy environments (because others raise voice - stapes fixation prevents transmission of low-frequency background noise)
• Tinnitus (low frequency)
• Family history positive
• Flamingo pink (Schwartze sign): Pinkish glow through TM due to increased vascularity of active otospongiosis (seen in early active disease)

C. Investigations

• Pure tone audiometry:
  • Carhart's notch at 2000 Hz (dip in BC at 2 kHz - a mechanical effect of stapes fixation, NOT true SNHL)
  • CHL with bone conduction better than air conduction
• Tympanometry: Type As (stiffness type - reduced compliance, normal peak pressure)
• Gelle's test: NEGATIVE (fixed stapes)
• Stapedial reflex: ABSENT
• HRCT temporal bone: Halo sign (radiolucency around cochlea - "double ring sign")

D. Management

Medical (limited role):

• Sodium fluoride - retards progression; converts active spongiotic bone to stable sclerotic bone (250-500 mg/day)
• Bisphosphonates - emerging evidence
• Calcium and Vitamin D

Surgical (treatment of choice):

• Stapedectomy / Stapedotomy (standard treatment)
  • Stapedotomy is preferred (small hole in footplate, piston prosthesis)
  • Prosthesis: Teflon, stainless steel, titanium
  • Success rate: >90% - postoperative BC thresholds improve (Carhart's notch disappears)
  • Complication: Perilymph fistula, SNHL (dead ear - 1%), tinnitus, taste disturbance (chorda tympani)
• Hearing aid - alternative if surgery refused or not feasible

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SECTION 19: BELL'S PALSY

A. Symptoms and Signs

• Definition: Acute idiopathic unilateral lower motor neurone (LMN) facial nerve palsy - diagnosis of exclusion
• Cause: Believed to be reactivation of Herpes simplex virus type 1 causing inflammation and edema of facial nerve within the Fallopian canal

Symptoms:

• Sudden onset unilateral facial weakness (over hours to days)
• Inability to close eye (lagophthalmos) - most dangerous symptom
• Drooping of corner of mouth
• Drooling of saliva
• Difficulty chewing, whistling
• Hyperacusis (if nerve to stapedius involved)
• Loss of taste (anterior 2/3 tongue) - chorda tympani involvement
• Decreased lacrimation/salivation - if proximal to geniculate ganglion
• Post-auricular pain (often precedes palsy by 24-48 hrs)

Signs:

• Unilateral LMN facial palsy (all branches affected - forehead spared in UMN)
• Inability to raise eyebrow, close eye, puff cheek, smile
• Bell's phenomenon: Eyeball rolls upward on attempting to close eye (protective reflex - positive = intact CN III)
• Nasolabial fold flattened
• Loss of corneal reflex (ophthalmic branch via VII efferent)
• Grading: House-Brackmann scale (I = normal, VI = complete paralysis)

B. Investigations

• Nerve conduction studies (Electroneuronography - ENoG)
• Audiometry
• MRI with gadolinium (if atypical or no recovery)
• Blood sugar, serology for HSV/VZV

C. Treatment

1. Eye care (most important):
   • Artificial tears (lubricant eye drops) during day
   • Eye ointment + taping eye shut at night
   • Protective glasses
2. Corticosteroids (first-line):
   • Prednisolone 1 mg/kg/day (maximum 60 mg) for 10 days, started within 72 hours
   • Improves recovery rate significantly
3. Antiviral (controversial but used):
   • Acyclovir or Valacyclovir + steroids (mainly for severe/complete palsy)
4. Physiotherapy: Facial muscle exercises
5. Surgery: Facial nerve decompression (controversial, rarely done now)

• Prognosis: 85% recover completely within 3-6 months; incomplete palsy has better prognosis

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SECTION 20: MENIERE'S DISEASE

A. Aetiopathogenesis

• Definition: Idiopathic condition characterized by endolymphatic hydrops (increased endolymph volume/pressure in the membranous labyrinth)
• Pathology:
  • Impaired endolymph absorption (possibly due to endolymphatic sac dysfunction)
  • Endolymph accumulates → distension of scala media and saccule
  • Eventually: Reissner's membrane ruptures → endolymph mixes with perilymph → acute attack of vertigo
• Possible causes:
  • Autoimmune (strong evidence)
  • Allergy
  • Viral infection
  • Vascular insufficiency
  • Anatomical abnormality (narrow endolymphatic duct/sac)

B. Clinical Features - Classic Triad

"ELV" - Episodic Vertigo + Low-frequency hearing Loss + Tinnitus

1. Episodic vertigo:
   • Sudden, severe, rotatory, lasting 20 minutes to 24 hours
   • Accompanied by nausea and vomiting
   • NOT triggered by head movement (unlike BPPV)
   • Patient is incapacitated during attack
2. Fluctuating SNHL:
   • Low-frequency loss initially (distinguishes from other SNHL)
   • Fluctuates - worse during attacks, improves between attacks
   • Progressive with repeated attacks
3. Tinnitus:
   • Low-pitched, roaring/sea-shell quality
   • Increases before/during attacks
4. Aural fullness/pressure (4th feature - ear congestion)

• Unilateral in 85% of cases
• Lermoyez syndrome: Variant where tinnitus + hearing loss precede vertigo, and vertigo relieves them

C. Investigations

• Audiometry: Low-frequency SNHL; type B or C tympanogram (normal in early stages; flat curve in end-stage)
• Electrocochleography (ECoG): SP:AP ratio > 0.3-0.4 (summating potential to action potential ratio elevated) - most specific
• Glycerol dehydration test (Glycerol test): Oral glycerol improves hearing by 15 dB = positive → supports diagnosis
• Caloric test: Reduced or absent response on affected side (canal paresis)
• Furosemide test: Similar principle to glycerol test
• MRI: To exclude acoustic neuroma

D. Management

Acute Attack:

• Bed rest in a quiet, dark room
• Prochlorperazine (vestibular sedative) IM/oral
• Dimenhydrinate (antihistamine/antiemetic)
• IV fluids if vomiting

Prophylactic (Between attacks):

• Low-salt diet (<1.5 g Na/day) + fluid restriction - most important lifestyle measure
• Betahistine (16 mg TDS) - improves labyrinthine microcirculation; reduces attack frequency
• Diuretics: Hydrochlorothiazide + triamterene (reduces endolymph production)
• Stress management, avoid caffeine, alcohol, nicotine

Surgical/Interventional (refractory cases):

• Intratympanic gentamicin injection - chemical labyrinthectomy (destroys vestibular function; risk to hearing)
• Intratympanic steroids (dexamethasone) - controls vertigo, preserves hearing
• Endolymphatic sac decompression/shunt - drains excess endolymph (controversial efficacy)
• Vestibular nerve section - definitive for vertigo, preserves hearing
• Labyrinthectomy - if no useful hearing; complete cure of vertigo

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Source references: Cummings Otolaryngology Head and Neck Surgery; Scott-Brown's Otorhinolaryngology Head & Neck Surgery Vol 2; K.J. Lee's Essential Otolaryngology