Description

• Tinnitus is a perceived sensation of sound in the absence of an external acoustic stimulus; often described as a ringing, hissing, buzzing, clicking, or whooshing
• Derived from the Latin word tinnire, meaning “to ring”
• May be heard in one or both ears or centrally within the head
• Two types: subjective (most common) and objective tinnitus
  • Subjective tinnitus: perceived only by the patient; can be continuous, intermittent, or pulsatile
  • Objective tinnitus: audible to the examiner; rare
• Primary tinnitus: idiopathic with or without sensorineural hearing loss (SNHL) (1)
• Secondary tinnitus: associated with a specific cause (other than SNHL)

Epidemiology

Incidence

• Incidence is increasing in association with excessive noise exposure.
• Higher rates of tinnitus in smokers, hypertensives, diabetics, and obese patients

Prevalence

• Tinnitus reported by 35 to 50 million adults in the United States; although underreported, 12 million seek medical care.
• Affects 10–15% of adults (2)
• Prevalence increases with age and peaks in 6th decade of life; estimated 8% prevalence reported post–COVID-19 infection
• Prevalence of 13–53% in general pediatric population
• Ethnic: whites > blacks and Hispanics
• Gender: males > females

Etiology and Pathophysiology

• Precise pathophysiology is unknown; numerous theories have been proposed. Ototoxic agents or noise exposure damage hair cells so that there is abnormal neural activity in the auditory cortex. Inflammation may play a role.
• Causes of secondary tinnitus (2):
  • Otologic: cholesteatoma, cerumen impaction, foreign body, middle ear effusion, otosclerosis, Ménière disease, vestibular schwannoma, patulous Eustachian tube
  • Medications: anti-inflammatory agents (aspirin, NSAIDs); antimalarial agents, antimicrobial drugs (aminoglycosides, macrolides); antineoplastic agents, loop diuretics, miscellaneous drugs (antiarrhythmics, antiulcer, anticonvulsants, antihypertensives); anesthetics
  • Somatic: temporomandibular joint (TMJ) dysfunction, head or neck injury
  • Neurologic: multiple sclerosis, spontaneous intracranial hypertension, vestibular migraine, type I Chiari malformation, palatal myoclonus, idiopathic stapedial muscle spasm
  • Infectious: viral (impact of COVID-19 on tinnitus is unknown), bacterial, fungal
  • Metabolic: diabetes mellitus, dyslipidemia, vitamin B₁₂ deficiency
  • Vascular: aortic or carotid stenosis, venous hum, arteriovenous fistula or malformation, vascular tumors, high cardiac output state (anemia)

Genetics
Limited evidence to support a genetic component

Risk Factors

• Hearing loss (but can have tinnitus with normal hearing)
• High-level noise exposure
• Advanced age
• Use of ototoxic medications (Some are irreversible.)
• Otologic disease (otosclerosis, Ménière disease, cerumen impaction)
• Depression and anxiety are associated with increased odds of tinnitus.

General Prevention

• Avoid loud noise exposure and wear appropriate ear protection to prevent hearing loss.
• Monitor ototoxic medications and avoid prescribing more than one ototoxic agent concurrently.

Commonly Associated Conditions

• SNHL caused by presbycusis (age-associated hearing loss) or prolonged loud noise exposure
• Conductive hearing loss due to cerumen, otosclerosis, cholesteatoma
• Psychological disorders: depression, anxiety, insomnia, suicidal ideation
• Despair, frustration, interference with concentration and social interactions, work hindrance