Sudden Sensory Neural Hearing Loss

Jeetendra Bhandari

Introduction

• Definition• 30 dB or more of sensory neural hearing loss over least three contiguous

frequencies occurring within a period of 3 days or less

• Mostly unilateral

• May be accompanied with tinnitus or temporary spell of vertigo

Aetiology

• Cause not well known(idiopathic)

• Three aetiologic factors considered-viral, vascular or the rupture of cochlear membrane

• Spontaneous perilymph fistula may form in the oval or round windows

• Other factors• Infection(mumps, herpes zoster, meningitis, otitis media)

• Trauma(head injury, ear operation, noise trauma, barotrauma)

• Vascular(haemorrhage (leukemia), embolism or thrombosis of labyrinthine or cochlear artery or their vasospasm)

• Ear( otologic ) (Meniere's disease, Cogan’s syndrome, large vestibular aqueduct)

• Toxic(ototoxic drugs, insecticides)

• Neoplasm( acoustic neuroma, Metastases in cerebellopontine angle, carcinomatous neuropathy)

• Miscellaneous(multiple sclerosis, hypothyroidism, sarcoidosis)

Clinical Presentation

• Sudden onset hearing loss• Less than 3 days

• Usually unilateral• Left side possibly more common (55%)• Bilateral 2%

• Median age 40-54

• Equal among males and females

• Awakening from sleep

• Hearing a “popping” prior to hearing loss

• Aural fullness

• Tinnitus

• Vertigo

Clinical evaluation

• History

• Complete head and neck exam• Pneumatoscopsy to evaluate for fistula sign

• Audiogram including pure-tone audiometry (PTA), speech reception threshold (SRT), and speech discrimination scores (SDS)

• Tympanometry

• +/- Auditory brainstem response (ABR) and otoacoustic emission (OAE)

• Electronystagmography (ENG) if vestibular symptoms and/or signs are present

Investigation

• CBC with differential count• Polycythemia, leukemia, thrombocytosis

• Electrolytes

• Erythrocyte sedimentation rate (ESR)• Nonspecific, autoimmune or inflammatory marker• Antinuclear antibody or 68 kD antibody

• Rheumatoid factor (RF)

• FTA-Abs (Syphilis)

• Coagulation profile

• Thyroid function testing

• Lipid profile

• Blood glucose

• Radiography• MRI with gadolinium

• 0.8%-2% of patients with SSNHL have been diagnosed with Cerebellopontine Angle tumors

• Non-contrasted CT of temporal bones in younger patients• Mondini malformation

• Enlarged vestibular aqueduct

Treatment

• Cause unknown so, main stay of treatment is based on observation or experience

• Many treatment protocol suggested for idiopathic sensorineural sudden hearing loss

• None of protocol shown benefit over benefit of spontaneous recovery(50-60%) within 2 weeks

Treatment

• Bed rest

• Steroids therapy• Prednisolone 40-60 mg (single morning dose for 1 week; then tapering in 3

week time)

• Acts as anti-inflammatory agent and relieve oedema

• Found useful in idiopathic sudden hearing loss of moderate degree

• Inhalation of carbogen(5%CO2 and 95% O2)• Increase cochlear blood flow

• Improves oxygenation

• Vasodilator Drugs

• Low molecular weight dextran• Decrease blood viscosity

• Contraindicated if cardiac failure and bleeding disorders

• Hyperbaric oxygen therapy• Raise concentration of oxygen in labyrinthine fluids

• Improve cochlear function

• Low salt diet and a diuretics• Some benefit in Meniere’s disease

• Intratympanic steroids therapy• Raises local concentration of steroids in cochlear fluid

• Avoids side effect of systemic therapy

Prognosis

• About half of patient recover spontaneously within 15 days

• Chances of recovery after 1 months POOR

• Severe hearing loss and that associated with vertigo have poor prognosis

• Younger patient below 40 and those with moderate lossbetterprognosis

Otitis Media with EffusionSynonyms: Serous Otitis Media, Secretory otitis media, Mucoid otitis

media, “glue ear”

Introduction

• Presence of fluid without signs or symptoms of ear infection

• Effusion thick and viscid(often); thin and serous(sometime)

• Sterile fluid

• 90% of children suffer before school age (usually 6 months to 4 years)

• 30-40% of children with recurrent otitis media with effusion

• 5-10% last greater than 1 year

Pathogenesis

• Malfunctioning of Eustachian tube• Fail to aerate middle ear

• Unable to drain fluid

• Increased secretory activity of middle ear mucosa• Increase in number of mucus or serous secreating cells

Aetiology

• Malfunction of Eustachian tube• Adenoid hyperplasia• Chronic rhinitis and sinusitis• Chronic tonsillitis(mechanical obstruction on Eustachian tube)• Benign and malignant tumors of nasopharynx(nasopharyngeal fibroma,

Angiofibroma, choanal polyp, squamous papilloma, Lympoma)• Palatine defect( cleft palate, palatal paralysis)

• Allergy• Seasonal allergy to inhalants or foodstuff• Obstruct Eustachian tube by oedema• Increase secretory activities

• Unresolved otitis media• Due to inadequate antibiotic therapy in acute suppurative otitis

media(inactivate infection; fail to resolve)

• Stimulate mucosa to secrete more fluids

• number of goblet cell and mucous gland increases

• Viral infection• Adeno and rhinoviruses of upper respiratory tract; invade middle ear mucosa

• Stimulate to increase secretory activities

Clinical features

• Symptoms• Hearing loss

• presenting symptom

• insidious onset rarely exceed 40 dB

• Accidently found in audiometric screening test(in some cases)

• Delayed and defective speech• Due to hearing loss

• Mild earache• History of upper respiratory tract infection with mild earache

Otoscopic finding

• Tympanic membrane• dull and opaque

• Loss of light reflex

• Yellow, grey or bluish in colour

• Thin lash of blood vessels along handle of malleus or at periphery of tympanic membrane

• Retraction

• Sometimes, appear full or slightly bulging in posterior part(due to effusion)

• Fluid level and air bubble when fluid is thin

Hearing Tests

• Tuning fork tests

• Audiometry• Conductive hearing loss of 20-40dB

• Occasionally, associated sensorineural hearing loss (fluid pressing on round window membrane) disappear with evacuation of fluid

• Impedance audiometry• Objective test for infants and children

• Presence of fluid by reduced compliance and flat curve with shift to negative side

• X-ray mastoid: clouding or air cells due to fluid

Treatment

• AimRemoval of fluid and prevention of recurrence

• Strategy• Medical

• Surgical

Medical

• Decongestant• Topical decongestant(nasal drop, spray or systemic decongestants)

• Relieve oedema or oestachian tube

• Antiallergic measure• Antihistamine or steroids

• Identification of allergen and desensitization

• Antibiotics• In case of upper respiratory tract infection

• In unresolved acute suppurative otitis media

• Middle ear aeration• Repeated Valsalva manoeuver

• Eustachian tube catherization(for ventilation and drainage of fluid)

• Politerization or Eustachian tube catheterization(for ventilation and drainage of fluid)

• Chewing gum for children and encourage them to swallow opens tube

Surgical

• When medical treatment alonTympanotomy or cortical mastoideedoesn’t help

• Surgical procedure include• Myringotomy and aspiration of fluid

• Grommet insetion

• Tympanotomy or cortical mastoidectomy

• Surgical treatment of causative factor

• Myringotomy and aspiration of fluid• Incision made in tympanic membrane and fluid

aspirated with suction• For thick mucus saline or mucolytics

(chrymotrypsin solution)• Two incision made at tympanic

membrane(anteroinferior and anterosuperiorquadrants to aspirate thick, glue like secretion)

• Grommet insertion• If myringotomy and aspiration combined with medical

measure fails• Provide continued aeration or middle ear• Can be kept for weeks

• Tympanotomy or cortical mastoidectomy• Required for removal of loculated thick fluid

• In associated pathology(cholesterol granuloma)

• Surgical Treatment of causative factor• Adenectomy

• Tonsillectomy

• Usually done at the time of myringotomy

Sequelae of chronic secretory Otitis media

• Atrophic tympanic membrane and atelectasis of the middle ear• Due to dissulation of fibrous layer

• Becomes thin and atrophic and reacts into middle ear

• Ossicular necrosis• Long process of incus, stapes suprastructures get necrosed

• Increases the conductive hearing loss more than 50 dB

• Tympanosclerosis• Hyalinized collagen with chalky deposits may be seen in tympanic membrane,

around ossicles or their joints leading to fixation

• Retraction pockets and cholesteatoma• Thin atrophic part of pars tensa may get invaginated to form retraction

pockets or cholesteatoma

• Cholesterol granuloma• Due to stasis of secretion in middle ear and mastoid

References

• Disease of Ear, Nose and Throat and head and neck surgery. DhingraPL, Dhingra S. 6th ed. Hearing loss. 35-37.

• Disease of Ear, Nose and Throat and head and neck surgery. DhingraPL, Dhingra S. 6th ed. Disorders of middle ear. 64-68.

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