Tinnitus - Differential Diagnosis

Classification Framework

DD: Subjective Nonpulsatile Tinnitus

Otologic (Inner Ear)

• Sensorineural hearing loss (SNHL) - most common cause overall; bilateral tinnitus + symmetric SNHL typically requires no further imaging
• Presbycusis (age-related hearing loss)
• Noise-induced hearing loss (NIHL) - acoustic trauma (single event or chronic occupational)
• Meniere disease - classic triad: episodic vertigo + fluctuating low-frequency SNHL + tinnitus (often roaring quality)
• Labyrinthitis (viral or bacterial)
• Sudden sensorineural hearing loss - medical emergency; requires urgent audiogram and treatment

Otologic (Middle Ear)

• Otosclerosis - conductive or mixed hearing loss + tinnitus
• Ossicular chain abnormalities / tympanic membrane perforation
• Cholesteatoma
• Otitis media (acute or chronic)
• Herpes zoster oticus (Ramsay Hunt syndrome)

Otologic (External Ear)

• Cerumen impaction / canal occlusion
• Otitis externa

Retrocochlear / Neurologic

• Vestibular schwannoma (acoustic neuroma) - unilateral tinnitus + asymmetric SNHL is the red flag; requires MRI with gadolinium of IAC/CPA
• Other cerebellopontine angle tumors (meningioma, epidermoid cyst, glomus jugulare)
• Multiple sclerosis
• Charcot-Marie-Tooth disease
• Epilepsy / migraine
• Basilar skull fracture / whiplash injury
• Meningitic effects

Ototoxic Medications

• Aminoglycosides (gentamicin, tobramycin)
• Aspirin / NSAIDs (dose-dependent, often reversible)
• Loop diuretics (furosemide, ethacrynic acid)
• Platinum-based antineoplastics (cisplatin - irreversible cochlear damage)
• Tricyclic antidepressants
• Quinine / antimalarials
• Heavy metals
• Oral contraceptives

Metabolic / Endocrine

• Hypothyroidism or hyperthyroidism (hypermetabolic state increases cochlear blood flow)
• Diabetes mellitus / hyperinsulinemia
• Hyperlipidemia
• Vitamin deficiencies (B12, zinc)
• Anemia (increased cardiac output)
• Pregnancy

Autoimmune

• Systemic lupus erythematosus (SLE)
• Systemic sclerosis
• Rheumatoid arthritis
• Autoimmune inner ear disease

Psychological / Psychiatric

• Anxiety disorder
• Depression
• These are associated conditions that amplify tinnitus perception through altered central auditory processing

Musculoskeletal

• Temporomandibular joint (TMJ) disorder - often unilateral, clicking, altered by jaw movement

Social Habits

• Caffeine, nicotine, alcohol, cocaine, marijuana (can worsen or precipitate tinnitus)

DD: Pulsatile Tinnitus (Arterial vs. Venous)

Arterial Causes (Objective or Subjective)

• Atherosclerotic carotid artery disease - most common arterial pulsatile tinnitus cause; bruit may be audible
• Arteriovenous malformation (AVM) / dural arteriovenous fistula
• Carotid-cavernous fistula
• Aneurysm (intracranial or extracranial)
• Persistent stapedial artery (congenital anomaly)
• Fibromuscular dysplasia of the carotid
• Carotid artery dissection
• Hypermetabolic states (hyperthyroidism, anemia, pregnancy) - increased arterial flow

Venous Causes

• Idiopathic intracranial hypertension (IIH) / pseudotumor cerebri - often bilateral pulsatile tinnitus in obese young women; venous hum that resolves with digital compression of the ipsilateral internal jugular vein
• Dehiscent jugular bulb (high-riding jugular bulb)
• Jugular vein stenosis or thrombosis
• Idiopathic venous hum

Vascular Tumors

• Glomus tympanicum - pulsatile tinnitus + reddish-blue retrotympanic mass on otoscopy
• Glomus jugulare - pulsatile tinnitus + lower cranial nerve palsies (IX, X, XI)
• Paraganglioma

Semicircular Canal / Inner Ear Dehiscence

• Superior semicircular canal dehiscence (SSCD) - autophony, pulsatile or nonpulsatile tinnitus, Tullio phenomenon; diagnosed by high-resolution CT

DD: Objective Tinnitus (Rare, ~1.5% of cases)

• Palatal myoclonus - rhythmic clicking from levator/tensor veli palatini spasms; audible as clicking
• Stapedial muscle myoclonus - rapid, irregular clicking
• Patulous Eustachian tube - autophony, breath-synchronous, worsened upright/weight loss
• Vascular tumors (glomus, AVM) - as above
• Arnold-Chiari malformation type I - associated with intracranial venous hypertension

Red Flags Requiring Urgent/Prompt Workup

Diagnostic Approach Summary

1. History - laterality, quality (ringing/clicking/pulsatile), onset, associated hearing loss, vertigo, medications, noise exposure, cardiovascular risk factors
2. Otoscopy - look for retrotympanic mass, cerumen, perforation, cholesteatoma
3. Audiogram - mandatory for all; defines symmetric vs. asymmetric SNHL
4. Tuning fork tests (Weber, Rinne) - bedside differentiation of conductive vs. sensorineural
5. Auscultation - periauricular, neck, chest for bruit/murmur
6. Imaging - reserved for: unilateral, pulsatile, asymmetric SNHL, or neurologic deficit
7. Labs - TSH, CBC, lipids, fasting glucose if metabolic cause suspected