Hearing Loss – Causes, Symptoms, Diagnosis, Treatment and Ongoing care

Basics

Description

  • Reduction in hearing manifested as decreased ability to detect or comprehend sound or speech
  • May be conductive hearing loss (CHL or air-bone gap), sensorineural hearing loss (SNHL), or both
  • System(s) affected: Auditory; External and middle ear (CHL), or inner ear (SNHL)

Alert

  • Any sudden SNHL (usually unilateral) is a medical emergency and should be referred to an otolaryngologist immediately.
  • Treatment with high-dose steroids (1 mg/kg/d prednisone for 14 days, followed by taper) should begin ASAP, ideally within 1–2 weeks of onset.
  • A simple 512-Hz tuning fork test lateralizes to unaffected ear in sudden SNHL (emergency) and lateralizes to the affected ear in CHL (not an emergency).

Epidemiology

  • Predominant age: All ages affected; common in children (CHL) and elderly (SNHL)
  • Predominant sex: Male = Female

Incidence

Hearing loss by age group:

  • 3 in 10 people >60 years old
  • 1 in 6 people ages 41–59 years old
  • 1 in 14 people ages 29–40 years old
  • At least 1.4 million children (18 or younger)

Prevalence

Hearing loss has doubled in the US during the past 30 years: 13.2 1971 to 28.2 million in 2000

Geriatric Considerations

  • Age-related hearing loss is the most common cause in the US.
  • ∼50% of people >85 years have hearing loss.
  • Hearing aids are underutilized.
  • Loss of communication is a source of emotional stress and a physical risk for elderly.

Pediatric Considerations

  • Congenital hearing loss:
    • 1–3/1,000 infants have hearing loss.
    • Mandatory newborn screening (OAE and ABR testing is ideal)
    • NICU screening before discharge
    • Audiologic testing after major intracranial infection (meningitis)

Pregnancy Considerations

Otosclerosis (a CHL) can worsen during pregnancy.

Risk Factors

  • Conductive:
    • Allergy
    • Chronic sinusitis
    • Cigarette smoking, 2nd-hand smoke
    • Sleep apnea with CPAP use
    • Adenoid hypertrophy
    • Nasopharyngeal mass
    • Eustachian tube dysfunction
    • Head trauma
    • Neuromuscular disease
    • Family history/heredity
    • Altered immunity
    • Prematurity and low birth weight
    • Young age
    • Craniofacial abnormalities (e.g., cleft palate, Down syndrome)
    • 3rd mobile window (superior canal dehiscence or large vestibular aqueduct)
  • Sensorineural:
    • Aging/older age
    • Loud noise/acoustic trauma
    • Dizziness/vertigo: Especially Ménière disease or history of labyrinthitis
    • Medications (aminoglycosides, loop diuretics, quinine, aspirin, chemotherapeutic agents)
    • Bacterial meningitis
    • Head trauma
    • Atherosclerosis
    • Vestibular schwannoma/skull base neoplasm
    • Previous ear surgery
  • Sensorineural, pediatric-specific:
    • Postnatal asphyxia
    • NICU hospitalization
    • Mechanical ventilation lasting ≥5 days
    • In utero infections (TORCH)
    • Toxemia of pregnancy
    • Maternal diabetes
    • Rh incompatibility
    • Prematurity or birth weight <1,500 g
    • Hyperbilirubinemia; exchange transfusions
    • Anomalous temporal bone (Mondini or large vestibular aqueduct)
    • Infectious diseases: Chickenpox, measles, encephalitis, influenza, mumps

Genetics

  • Connexin 26 (13q11–12): Most common cause of nonsyndromic genetic hearing loss
  • Mitochondrial mutations or disorders:
    • May predispose to aminoglycoside ototoxicity
  • Otosclerosis: Familial; no clear genetic cause
  • Most common congenital syndromes:
    • Hemifacial microsomia
    • Stickler syndrome
    • Congenital cytomegalovirus
    • Usher syndrome
    • Branchio-oto-renal syndrome
    • Pendred syndrome
    • CHARGE association
    • Neurofibromatosis type II
    • Waardenburg syndrome

General Prevention

  • Limit noise exposure; use hearing protection when exposure cannot be avoided.
  • Avoid ear canal instrumentation (Q-tips, etc.).
  • Limit ototoxic medications.

Pathophysiology

  • CHL:
    • Hearing loss can result from middle ear effusion, obstruction of canal (cerumen/foreign body, osteomas/exostoses, cholesteatoma, tumor), loss of continuity (ossicular discontinuity), stiffening of the components (myringosclerosis, tympanosclerosis, and otosclerosis), and loss of the pressure differential across the TM (perforation).
  • SNHL:
    • Damage along the pathway from oval window, cochlea, auditory nerve, and brainstem. Examples include vascular/metabolic insult, mass effect, infection and inflammation, acoustic trauma (see below).
    • Noise-induced hearing loss is caused by acoustic insult that affects outer hair cells in organ of Corti causing them to be less stiff. Over time, severe damage occurs with fusion and loss of stereocilia. Eventually may progress to inner hair cells and auditory nerve as well.
  • Large vestibular aqueduct or superior canal dehiscence: 3rd mobile window shunts acoustic energy away from cochlea.

Sensorineural hearing loss, Conductive hearing loss, Eustachian tube, hearing aids, otolaryngologist, middle ear, hypertrophy, Abscess,

Diagnosis

History

  • Difficulty hearing:
    • Rapid vs gradual decline: Rapid (<2 weeks’ duration) is a medical emergency. If suspect sudden SNHL, refer to ENT ASAP.
    • Difficulty with discrimination
    • Difficulty hearing in crowds
    • Frequently having to ask speakers to repeat
    • Friends/family complain of hearing loss
    • TV, phone volume increasing
  • Tinnitus, bilateral or unilateral
  • Otalgia
  • Otorrhea, clear or purulent
  • Dizziness or vertigo
  • Ear fullness
  • Autophony (hearing own voice louder or echoing)
  • Facial nerve twitching or asymmetry
  • Depression
  • Anxiety
  • History of ear infections or ear surgeries
  • History of trauma or noise exposure
  • Family history of hearing loss
  • History of recent viral infection
  • Nasal obstruction
  • Frequent epistaxis

Physical Exam

  • 512-Hz tuning fork tests:
    • Sensorineural loss:
      • Placed on the forehead: Lateralizes to nonaffected ear (Weber test)
      • Placed on the mastoid and then next to ear; heard louder next to ear (Rinne test)
    • Conductive loss:
      • Placed on the forehead or teeth lateralizes to affected or symptomatic ear
      • Placed on the mastoid and then next to ear; heard louder behind the ear on the side of conductive deficit
  • Otoscopy: Assess for deformity, canal patency, and otorrhea, TM integrity/retraction/mobility with insufflation, canal, or middle ear mass.
  • Facial symmetry
  • Cranial nerve exam
  • Nasopharyngoscopy: Adenoid hypertrophy or nasopharyngeal mass (mandatory in adult patient with new unilateral serous effusion)
  • Pediatric: Survey for syndromic anomalies

Diagnostic Tests & Interpretation

Lab

Often labs are not needed. If indicated:

  • Pendred syndrome (goiter, mental retardation + SNHL): Perchlorate test, thyroid function tests
  • Alport syndrome (nephritis + SNHL): Urinalysis, renal function tests
  • Jervell and Lange-Nielsen syndrome (syncope, family history of sudden death + SNHL): EKG
  • Any pediatric patient with SNHL: Genetic testing for connexin 26, mitochondrial studies
  • TORCH screening test
  • RPR confirmed with FTA-ABS
  • Lyme titer in endemic areas
  • Antinuclear antibodies and sedimentation rate as a screen for autoimmune disease

Imaging

Often imaging is not required; if indicated:

  • Fine-cut CT temporal bones without contrast
  • MRI of brain and brainstem with gadolinium

Diagnostic Procedures/Surgery

  • Audiometry: Pure tone (air and bone), speech testing, and impedance (middle ear pressure) testing
  • Tympanometry: Type B or C tympanograms indicate fluid or retraction, respectively. Negative middle ear peak pressures seen even with normal (Type A) tympanograms.
  • Other tests:
    • Auditory brainstem response
    • Otoacoustic emissions: Echo of the cochlea
    • Behavioral (visual reinforcement) audiometry; used in children 6 months–5 years
  • Myringotomy for aspiration of middle ear fluid is both diagnostic and therapeutic.

Pathological Findings

Varies depending on etiology

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Differential Diagnosis

  • Conductive:
    • Cerumen impaction/foreign body
    • Perforation of tympanic membrane
    • Middle ear fluid (serous otitis media)
    • Acute otitis media
    • Adhesive otitis media
    • Cholesteatoma
    • Ossicular erosion (infection, cholesteatoma)
    • Myringosclerosis/tympanosclerosis
    • Temporal bone fracture
    • Otosclerosis
    • Congenital malleus fixation
    • Glomus tumor
    • Congenital aural atresia
    • Osteogenesis imperfecta
    • Superior canal dehiscence
  • Sensorineural:
    • Presbycusis (hearing loss related to aging)
  • Noise-induced (recreational, occupational)
    • Ménière disease
    • Ototoxicity (aspirin, quinine, aminoglycosides)
    • Viral labyrinthitis
    • Cerebellopontine angle tumor
    • Large vestibular aqueduct syndrome
    • Syndromic hearing loss
    • Congenital cochlear malformation
    • Labyrinthine artery infarct
    • Idiopathic
    • Syphilis
    • CMV
    • Rubella
    • Temporal bone fracture
    • Metabolic (hyper/hypothyroid)
    • Paget disease
    • Perilymphatic (inner ear) fistula
    • Autoimmune disease

Treatment

  • Early detection: If sudden single-sided deafness, refer ASAP to otolaryngologist for hearing testing and prompt steroid therapy.
  • Hearing rehabilitation: Hearing aids, cochlear implants for patients with bilateral severe to profound hearing loss

Medication

  • Depends on cause. Hearing loss is a broad topic with many possible etiologies.
  • Sudden SNHL: High-dose oral steroids: 1 mg/kg or 60–100 mg/d prednisone or 12–16 mg/d dexamethasone for 14 days, followed by a taper:
    • Some recent papers suggest simultaneous use of oral and intratympanic steroid use results in better outcomes. There is an ongoing multi-center trial comparing the efficacy of oral steroids and intratympanic steroids (1)[A],(2).
    • Evidence is conflicting regarding use of systemic steroids in sudden SNHL (2)[A].
  • Vasodilators and vasoactive substances are being used to treat idiopathic SNHL, but evidence is conflicting (3)[A].

Additional Treatment

Issues for Referral

  • Audiology: If hearing loss is suspected, referral to audiology is warranted. Audiologists also provide hearing aid options and maintenance.
  • Genetics: If congenital syndrome or familial hearing loss is suspected
  • Speech therapist: If speech delay or speech impediment is present
  • Endocrinology: Pendred syndrome, other associated endocrine disorder (hypo-/hyperthyroidism)
  • Cardiology: Jervell and Lange-Nielsen syndrome
  • Ophthalmology: Usher syndrome
  • Neurosurgery: CPA lesion, intracranial complication of middle ear disease

Surgery/Other Procedures

  • CHL often has surgical options for repair:
    • Tympanostomy and tube placement
    • Tympanoplasty
    • Mastoidectomy
    • Ossicular chain reconstruction
    • Stapedectomy/stapedotomy
    • Canaloplasty
  • Those with profound bilateral SNHL may qualify for cochlear implantation.

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Audiogram and clinical exam are primary means of monitoring patient.

Diet

Salt restriction to 2 g/d is helpful for Ménière disease patients.

Prognosis

SNHL is usually permanent and progressive.

Complications

Acute middle ear problems may become chronic (perforations, cholesteatoma).

References

1. Plontke SK, Löwenheim H, Mertens J, et al. Randomized, double blind, placebo controlled trial on the safety and efficacy of continuous intratympanic dexamethasone delivered via a round window catheter for severe to profound sudden idiopathic sensorineural hearing loss after failure of systemic therapy. Laryngoscope. 2009;119:359–69.

2. Wei BP, Mubiru S, O’Leary S et al. Steroids for idiopathic sudden sensorineural hearing loss. Cochrane Database Syst Rev. 2006;CD003998.

3. Agarwal L, Pothier DD et al. Vasodilators and vasoactive substances for idiopathic sudden sensorineural hearing loss. Cochrane Database Syst Rev. 2009;CD003422.

Additional Reading

Chau JK, Lin JR, Atashband S, Irvine RA, Westerberg BD et al. Systematic review of the evidence for the etiology of adult sudden sensorineural hearing loss. Laryngoscope. 2010;120:1011–21.

For information on NIH-funded study. Available at: http://www.suddendeafness.org

National Institute on Deafness and Other Communication Disorders. At: http://www.nidcd.nih.gov/health/hearing/.

Ragab A, Shreef E, Behiry E, et al. Randomised, double-blinded, placebo-controlled, clinical trial of ozone therapy as treatment of sudden sensorineural hearing loss. J Laryngol Otol. 2008:1–7.

Codes

ICD9

  • 389.00 Conductive hearing loss, unspecified
  • 389.10 Sensorineural hearing loss, unspecified
  • 389.20 Mixed hearing loss, unspecified
  • 389.8 Other specified forms of hearing loss
  • 389.9 Unspecified hearing loss

Snomed

  • 15188001 Hearing loss (disorder)
  • 44057004 Conductive hearing loss (disorder)
  • 60700002 Sensorineural hearing loss (disorder)
  • 77507001 Mixed conductive AND sensorineural hearing loss (disorder)

Clinical Pearls

  • In sudden hearing loss, if a 512-Hz tuning fork test (Weber test) lateralizes to the unaffected ear, suspect sensorineural causes (emergent evaluation needed), but if it lateralizes to the affected ear, the diagnosis is conductive hearing loss (not an emergency).
  • ∼50% of people >85 years have hearing loss, so encourage screening and treatment, especially in pat

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