Tinnitus and Hearing Loss Causes and Considerations

Primary Causes of Tinnitus and Hearing Loss

• Sensorineural hearing loss (SNHL) is the most common underlying cause of tinnitus, with various etiologies, according to the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• Noise exposure (occupational or recreational) can cause tinnitus and hearing loss, as reported by the International Journal of Occupational and Environmental Medicine 3, 4
• Sudden sensorineural hearing loss is a cause of tinnitus, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 2
• Cochlear synaptopathy ("hidden hearing loss") can trigger irreversible degeneration of auditory nerve fibers without affecting outer hair cells or permanent threshold shifts, leading to difficulty understanding speech in noisy environments, as found by the International Journal of Occupational and Environmental Medicine 4, 5

Secondary Causes of Tinnitus

• Otosclerosis is a cause of conductive hearing loss, which can lead to tinnitus, as reported by the American Academy of Otolaryngology-Head and Neck Surgery 2
• Neurodegeneration is a neurologic cause of tinnitus, as noted by the International Journal of Occupational and Environmental Medicine 5
• Anxiety and depression are psychogenic factors that can contribute to tinnitus, as found by the American Academy of Otolaryngology-Head and Neck Surgery 6

Important Clinical Considerations

• Tinnitus can be perceived as coming from within or outside the head, and can occur unilaterally or bilaterally, as described by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• The quality of tinnitus varies, with patients describing ringing, buzzing, clicking, pulsations, and other sounds, as reported by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• Approximately 10-15% of adults experience tinnitus, with prevalence increasing with age, as found by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2, 6
• Around 20% of adults with tinnitus require clinical intervention, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• Patients with tinnitus accompanied by severe anxiety or depression require prompt identification and intervention due to increased suicide risk, as reported by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2

Risk Factors for Developing Tinnitus and Hearing Loss

• Advanced age is a risk factor for developing tinnitus and hearing loss, as found by the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• Occupational noise exposure is a risk factor for developing tinnitus and hearing loss, as reported by the International Journal of Occupational and Environmental Medicine 3, 4
• Recreational noise exposure (concerts, firearms, etc.) is a risk factor for developing tinnitus and hearing loss, as noted by the International Journal of Occupational and Environmental Medicine 4

Tinnitus Etiology and Classification

Introduction to Tinnitus

• Tinnitus is not a disease but a symptom that can result from numerous underlying causes, ranging from cerumen impaction to vascular abnormalities, with primary tinnitus being idiopathic and secondary tinnitus associated with an identifiable underlying source 7

Classification of Tinnitus

• The American College of Radiology notes that subjective tinnitus is perceived only by the patient, is the most common type, and is often associated with sensorineural hearing loss 7, 8
• Objective tinnitus is audible to the examining healthcare provider and should prompt evaluation for underlying vascular abnormality 7, 9
• Pulsatile tinnitus is a repetitive sound coinciding with heartbeat, often vascular in origin 7, 10
• Non-pulsatile tinnitus is a continuous or constant non-synchronous sound 8, 9

Common Etiologies

• The American College of Radiology identifies presbycusis (age-related hearing loss) as a common etiology of tinnitus 8
• Vascular causes of tinnitus include arterial dissection, fibromuscular dysplasia of carotids, dural arteriovenous fistulas, arteriovenous malformations, carotid cavernous sinus fistulas, transverse sinus stenosis, sigmoid sinus diverticulum, persistent petrosquamosal sinus, prominent mastoid or condylar emissary veins, paragangliomas (glomus tumors), and vascular middle ear tumors 10
• Bony abnormalities such as superior semicircular canal dehiscence, sigmoid sinus wall dehiscence, high jugular bulb, and Paget disease affecting temporal bone can also cause tinnitus 10
• Neurologic causes of tinnitus include intracranial hypertension, neurodegeneration, and spontaneous intracranial hypotension 7, 10, 11
• Ototoxic medications can cause tinnitus, according to the American College of Radiology 8
• Psychogenic factors such as anxiety and depression can contribute to tinnitus 7, 12

Important Clinical Considerations

• Pulsatile tinnitus requires thorough evaluation for vascular abnormalities, as noted by the American College of Radiology and Praxis Medical Insights 7, 10
• Tinnitus with severe anxiety or depression requires prompt identification and intervention due to increased suicide risk, according to the American College of Radiology and the American Academy of Otolaryngology-Head and Neck Surgery 7, 12

Tinnitus Causes and Risk Factors

Primary Mechanism: Auditory System Dysfunction

• Sensorineural hearing loss is the single most common underlying cause of tinnitus, particularly in patients with bothersome tinnitus and no obvious ear pathology, according to the American Academy of Otolaryngology-Head and Neck Surgery 13, 14

Secondary Causes Requiring Identification

• Otosclerosis, a condition causing conductive hearing loss, is a secondary cause of tinnitus that requires identification, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery 13
• Menière's disease is another secondary cause of tinnitus that needs to be identified, according to the American Academy of Otolaryngology-Head and Neck Surgery 13
• Sudden sensorineural hearing loss is a secondary cause of tinnitus that requires prompt identification and intervention, as per the American Academy of Otolaryngology-Head and Neck Surgery 13

Clinical Classification That Guides Diagnosis

• Subjective tinnitus, which accounts for 70-80% of cases, is typically related to sensorineural hearing loss, as noted by the American College of Radiology 15
• Pulsatile tinnitus, which synchronizes with heartbeat, often has a vascular origin and requires thorough vascular evaluation, according to the American College of Radiology 15

Critical Risk Factors

• Age is the strongest demographic risk factor for tinnitus, with prevalence increasing from 1.6% in adults aged 18-44 years to 9.0% in those over 60 years, as reported by the American Academy of Otolaryngology-Head and Neck Surgery 13, 14

Important Clinical Pitfalls

• Patients with tinnitus accompanied by severe anxiety or depression require prompt identification and intervention, as they are at risk of suicide, according to the American Academy of Otolaryngology-Head and Neck Surgery 13, 14
• Approximately 20% of adults with tinnitus require clinical intervention, although most patients adapt to the phantom sound over time, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 13

Tinnitus with Vascular or Neuromuscular Etiology

Critical Distinguishing Features

• Tinnitus that wakes a patient from sleep is highly unusual and should immediately raise suspicion for objective tinnitus with a vascular or neuromuscular etiology, particularly pulsatile tinnitus from vascular abnormalities or typewriter tinnitus from neurovascular compression of the cochlear nerve 16
• The fact that tinnitus wakes the patient from sleep is a red flag that distinguishes this from typical subjective tinnitus, which comprises 70-80% of cases and rarely disrupts sleep to this degree 16

Primary Differential Diagnoses

• Pulsatile tinnitus is the most likely category when tinnitus is severe enough to wake someone from sleep 16
• Palatal or tympanic myoclonus represents pulse-asynchronous objective tinnitus from muscle contractions, creating clicking sounds from rhythmic muscle contractions in the middle ear or palate 16

Critical Clinical Approach

• First, determine if the tinnitus is pulsatile or non-pulsatile, as this fundamentally changes the diagnostic workup 16
• Key history elements to elicit include quality of sound, synchronization with heartbeat, laterality, associated symptoms, and positional variation 16
• Physical examination priorities include auscultation over the neck, periauricular area, and mastoid to detect objective tinnitus, otoscopic examination, and neurologic examination to detect focal deficits 16
• Imaging is strongly indicated for this presentation, contrary to typical tinnitus, with recommendations for MRI with heavily T2-weighted sequences, CT angiography or MR angiography/venography for suspected vascular causes of pulsatile tinnitus 16
• The American Academy of Otolaryngology-Head and Neck Surgery makes a strong recommendation against imaging for bilateral, non-pulsatile tinnitus without neurologic abnormalities or asymmetric hearing loss, but this patient's presentation does not fit that low-risk profile 16

Tinnitus Causes and Diagnostic Approach

Primary Causes to Consider

• Presbycusis (age-related hearing loss) represents a gradual, progressive decline in the ability to perceive high-frequency tones due to degeneration of hair cells in the ear and is the most common cause in older adults, according to the American College of Physicians, as published in the Annals of Internal Medicine 17

Tinnitus Causes and Diagnostic Approaches

Primary Auditory System Causes

• The American Academy of Otolaryngology-Head and Neck Surgery suggests that cerumen impaction is a simple, reversible cause of tinnitus identifiable on otoscopic examination 18
• The American Academy of Otolaryngology-Head and Neck Surgery recommends that middle ear infection or effusion can cause conductive hearing loss with associated tinnitus 18
• The American Academy of Otolaryngology-Head and Neck Surgery states that vestibular schwannoma (acoustic neuroma) almost always causes unilateral tinnitus with asymmetric hearing loss 18
• The American Academy of Otolaryngology-Head and Neck Surgery notes that cerebellopontine angle masses and auditory pathway lesions can cause tinnitus 18
• The American Academy of Otolaryngology-Head and Neck Surgery suggests that temporal bone fracture or head trauma with vascular injury can cause tinnitus 18
• The American Academy of Otolaryngology-Head and Neck Surgery recommends that severe psychiatric illness with tinnitus carries suicide risk and requires prompt intervention 18

Vascular Causes

• The American College of Radiology recommends that carotid artery atherosclerosis with stenosis should be evaluated in patients with pulsatile tinnitus 19
• The American College of Radiology suggests that unilateral or asymmetric tinnitus demands investigation for acoustic neuroma, requiring MRI of the internal auditory canals with contrast to exclude vestibular schwannoma 19
• The American College of Radiology states that pulsatile tinnitus is vascular until proven otherwise, requiring CT angiography/venography or MR angiography to identify potentially life-threatening vascular abnormalities 19