What are the causes of tinnitus?

Causes of Tinnitus

Tinnitus is most commonly caused by sensorineural hearing loss, but can also result from various other conditions including vascular abnormalities, neurologic disorders, and certain medications. 1

Primary Causes

• Hearing-related causes:

  • Sensorineural hearing loss (most common cause) 1, 2
  • Noise exposure (both acute and chronic) 2, 3
  • Age-related hearing loss (presbycusis) 4

• Otologic conditions:

  • Ménière's disease 4
  • Vestibular schwannoma (acoustic neuroma) 1, 4
  • Other ear pathologies affecting the auditory system

• Vascular causes:

  • Vascular abnormalities (causing pulsatile tinnitus) 1
  • Hypertension 5

• Neurologic disorders:

  • Traumatic brain injury 6
  • Migraine 6

• Medication-induced (ototoxic):

  • Certain antibiotics 4, 5
  • Other ototoxic medications 1, 5

Systemic Diseases Associated with Tinnitus

Systemic diseases can cause degenerative changes in the inner ear, leading to tinnitus:

• Hypertension (most common systemic cause - 47% of patients with systemic disease) 5
• Hypercholesterolemia (41% of patients with systemic disease) 5
• Diabetes 5
• Rheumatic diseases (22% of patients with systemic disease) 5
• Kidney diseases 5
• Thyroid disorders 5
• Small vessel disease 6

Psychological and Neuropsychiatric Factors

Tinnitus can be exacerbated by or associated with:

• Anxiety 1, 6
• Depression 1, 6
• Insomnia 1, 6
• Stress 6

Pathophysiological Mechanisms

Tinnitus can be categorized into:

• Objective tinnitus: Caused by sounds generated within the body that reach the ear through tissue conduction (less common) 4

• Subjective tinnitus: A phantom sensation with no physical sound source (more common), caused by:

  • Abnormal neural activity in the ear
  • Abnormal neural activity in the auditory nerve
  • Abnormal neural activity in the central nervous system 4

The pathophysiology often involves neural plasticity changes that:

• Alter the balance between excitation and inhibition in the nervous system
• Promote hyperactivity in auditory pathways
• Cause reorganization of specific parts of the nervous system 4

Important Clinical Considerations

• Unilateral tinnitus, pulsatile tinnitus, or tinnitus with asymmetric hearing loss requires prompt evaluation and may need imaging to rule out serious underlying causes 1, 2

• Patients with severe tinnitus and coexisting psychiatric illness require urgent assessment for suicide risk 1

• The anatomical location of the physiological abnormality in chronic subjective tinnitus is rarely in the ear itself but more often in the auditory nervous system 4

• Tinnitus is increasingly recognized as a neuropsychiatric condition involving both auditory and non-auditory cortical areas of the brain 6

• Since there are many different forms of tinnitus with different underlying causes, a single universal treatment is unlikely to be effective for all cases 4