What are the causes of tinnitus?

Causes of Tinnitus

Primary Cause: Sensorineural Hearing Loss

Sensorineural hearing loss (SNHL) is the single most common underlying cause of tinnitus, particularly in patients with bothersome tinnitus and no obvious ear pathology. 1

• Age-related hearing loss (presbycusis) is a leading etiology, with tinnitus prevalence increasing from 1.6% in adults aged 18-44 years to 9.0% in those over 60 years 1
• Noise exposure (occupational or recreational, including concerts and firearms) causes both tinnitus and permanent hearing damage 1
• Sudden sensorineural hearing loss requires prompt identification as it represents a medical emergency 1
• Cochlear synaptopathy ("hidden hearing loss") triggers irreversible auditory nerve fiber degeneration without affecting outer hair cells, leading to difficulty understanding speech in noisy environments 1

Secondary Otologic Causes

• Otosclerosis causes conductive hearing loss that can lead to tinnitus 1
• Menière's disease is a secondary cause requiring identification 1
• Cerumen impaction is a simple, reversible cause that should be ruled out 2
• Middle ear effusion and external ear infection can cause conductive hearing loss with tinnitus 2

Vascular Causes (Especially with Pulsatile Tinnitus)

Pulsatile tinnitus (synchronous with heartbeat) indicates an underlying vascular or structural abnormality in over 70% of cases and requires urgent imaging evaluation. 3

Arterial Causes

• Atherosclerotic carotid artery disease is the most frequent cause of pulsatile tinnitus, accounting for 17.5% of cases 3
• Arterial dissection is potentially life-threatening and requires urgent identification 3
• Fibromuscular dysplasia of carotids can cause turbulent flow 1

Arteriovenous Causes

• Dural arteriovenous fistulas (AVF) account for 8% of pulsatile tinnitus cases and can lead to hemorrhagic or ischemic stroke if untreated 3
• Arteriovenous malformations (AVMs) are high-flow vascular lesions that create abnormal shunting 1, 3
• Carotid cavernous sinus fistulas can cause pulsatile tinnitus 1

Venous Causes

• Idiopathic intracranial hypertension (pseudotumor cerebri) is the second most common cause of pulsatile tinnitus, particularly in young overweight women 3
• Transverse sinus stenosis and sigmoid sinus abnormalities are commonly associated with intracranial hypertension 1, 3
• Sigmoid sinus diverticulum or dehiscence can cause pulsatile tinnitus 3
• High-riding jugular bulb or jugular bulb dehiscence allows transmission of vascular sounds 3
• Persistent petrosquamosal sinus and abnormal condylar/mastoid emissary veins are aberrant venous anatomy causes 3

Vascular Tumors

• Paragangliomas (glomus tympanicum/jugulare) account for 16% of pulsatile tinnitus cases and appear as vascular retrotympanic masses on otoscopy 3
• Adenomatous middle ear tumors are less common vascular masses 3

Structural/Bony Abnormalities

• Superior semicircular canal dehiscence is a bony defect that allows transmission of vascular sounds 1, 3
• Sigmoid sinus wall dehiscence can cause pulsatile tinnitus 1
• Paget disease affecting temporal bone is a rare bony cause 1

Neurologic Causes

• Vestibular schwannoma (acoustic neuroma) almost always causes tinnitus, particularly when unilateral 1, 4
• Neurodegeneration can contribute to tinnitus 1
• Intracranial hypertension causes tinnitus and can lead to vision loss if missed 1, 3
• Spontaneous intracranial hypotension is a rare neurologic cause 1

Medication-Induced (Ototoxic)

• Ototoxic medications including certain antibiotics can cause tinnitus 1, 4
• Ibuprofen lists tinnitus as an adverse reaction in its FDA labeling 5

Psychogenic Factors

• Anxiety and depression are psychogenic factors that can contribute to tinnitus 1
• Patients with tinnitus accompanied by severe anxiety or depression require prompt identification and intervention due to increased suicide risk 1

Critical Clinical Distinctions

Subjective vs. Objective Tinnitus

• Subjective tinnitus (perceived only by patient) accounts for 70-80% of cases and is typically related to sensorineural hearing loss 1
• Objective tinnitus (audible to examiner) is rare and strongly suggests vascular pathology requiring immediate workup 1, 3

Unilateral vs. Bilateral

• Unilateral tinnitus has a higher likelihood of identifiable structural or vascular cause and warrants more aggressive investigation, including imaging to rule out acoustic neuroma 1, 6
• Bilateral, nonpulsatile tinnitus without localizing features typically does not require imaging 3, 6

Common Pitfalls to Avoid

• Missing dural AVF is life-threatening, as it can present with isolated pulsatile tinnitus before catastrophic hemorrhage 3
• Dismissing pulsatile tinnitus as benign is dangerous, as it almost always requires imaging evaluation 3
• Overlooking intracranial hypertension in young, overweight women with headaches can lead to permanent vision loss 3
• Inadequate otoscopic examination can delay diagnosis of vascular retrotympanic masses like paragangliomas 3