What are the causes of tinnitus?

Causes of Tinnitus

Tinnitus is a symptom, not a disease, with sensorineural hearing loss (SNHL) being the most common underlying cause, though it can result from numerous etiologies ranging from benign conditions like cerumen impaction to serious pathology like vascular abnormalities or tumors. 1, 2

Primary Causes

Auditory System Pathology

• Sensorineural hearing loss (SNHL) is the predominant cause of tinnitus, particularly in patients with bothersome tinnitus and no obvious ear pathology 1, 2
• Presbycusis (age-related hearing loss) is a common etiology, with tinnitus prevalence increasing from 1.6% in adults aged 18-44 years to 9.0% in those over 60 years 1, 2
• Noise exposure (occupational or recreational) causes both tinnitus and hearing loss 2, 3
• Cochlear synaptopathy ("hidden hearing loss") triggers irreversible degeneration of auditory nerve fibers without affecting outer hair cells, leading to difficulty understanding speech in noisy environments 2
• Sudden sensorineural hearing loss is an important acute cause requiring prompt evaluation 2

Conductive and Middle Ear Pathology

• Otosclerosis causes conductive hearing loss that can lead to tinnitus 2, 4
• Cerumen impaction is a simple, reversible cause 1
• Otitis (middle ear inflammation) can produce tinnitus 4

Secondary Causes Requiring Specific Evaluation

Vascular Etiologies (Typically Pulsatile Tinnitus)

• Arterial abnormalities: arterial dissection, fibromuscular dysplasia of carotids, carotid artery atherosclerosis 2, 4
• Arteriovenous malformations: dural arteriovenous fistulas, arteriovenous malformations, carotid cavernous sinus fistulas 2, 4
• Venous abnormalities: transverse sinus stenosis, sigmoid sinus diverticulum, persistent petrosquamosal sinus, prominent mastoid or condylar emissary veins 2
• Vascular tumors: paragangliomas (glomus tumors), vascular middle ear tumors 2, 4

Structural/Bony Abnormalities

• Superior semicircular canal dehiscence 2
• Sigmoid sinus wall dehiscence 2
• High jugular bulb 2
• Paget disease affecting temporal bone 2

Neurologic Causes

• Vestibular schwannoma (acoustic neuroma) - individuals with this tumor almost always have tinnitus 4, 5
• Intracranial hypertension 2, 4
• Spontaneous intracranial hypotension 2
• Neurodegeneration 2, 6
• Head or cervical vertebra trauma 3, 6
• Traumatic brain injury 6

Medication-Induced (Ototoxic)

• Ototoxic medications including certain antibiotics can cause tinnitus 2, 5
• Antidepressants (e.g., escitalopram) can cause bilateral, non-pulsatile tinnitus 7

Psychogenic and Comorbid Conditions

• Anxiety and depression are both risk factors for and consequences of tinnitus 2, 3, 8
• Menière's disease includes tinnitus as part of its symptom complex 4, 5
• Migraine is correlated with tinnitus 6
• Insomnia and stress exposure are associated factors 3, 6

Critical Clinical Distinctions

Classification by Perception

• Subjective tinnitus (70-80% of cases) is perceived only by the patient and is most commonly associated with SNHL 1, 2
• Objective tinnitus can be detected by the examining clinician and should prompt evaluation for underlying vascular abnormality 1, 2

Classification by Quality

• Pulsatile tinnitus is rhythmic, coinciding with heartbeat, often vascular in origin, and requires thorough evaluation for vascular abnormalities 1, 2
• Non-pulsatile tinnitus is continuous or constant, non-synchronous sound, almost always subjective and more common 1, 2

Localization

• Tinnitus can be unilateral, bilateral, or perceived inside the head 1, 2
• Unilateral or asymmetric tinnitus warrants comprehensive audiological examination to rule out serious pathology like vestibular schwannoma 1, 7

Important Clinical Pitfalls

Patients with tinnitus accompanied by severe anxiety or depression require prompt identification and intervention, as suicide has been reported in patients with tinnitus who have coexisting psychiatric illness. 1, 2, 7

• The quality of tinnitus varies widely, with patients describing ringing, buzzing, clicking, pulsations, roaring, or hissing sounds 1, 2
• Approximately 20% of adults with tinnitus require clinical intervention 1, 2
• Avoid dismissive statements like "there is nothing that can be done" - such attitudes are inappropriate and should be strongly condemned 4
• For non-pulsatile tinnitus that does not localize to one ear and is not associated with focal neurological abnormalities or asymmetric hearing loss, imaging studies are not recommended 1, 7