Differential Diagnosis of Tinnitus
The differential diagnosis of tinnitus must first distinguish between pulsatile and non-pulsatile presentations, as pulsatile tinnitus requires urgent imaging evaluation in nearly all cases due to identifiable structural or vascular causes in over 70% of patients, including life-threatening conditions like dural arteriovenous fistulas and arterial dissection. 1, 2
Primary Classification Framework
Pulsatile Tinnitus (Synchronous with Heartbeat)
This presentation demands immediate systematic evaluation for underlying vascular abnormalities:
Arterial Causes:
- Atherosclerotic carotid artery disease (most frequent cause at 17.5% of pulsatile cases) 2
- Arterial dissection (life-threatening, requires urgent identification) 2
- Arteriovenous malformations (high-flow vascular lesions with 2-3% annual hemorrhage risk) 2
Arteriovenous Shunting:
- Dural arteriovenous fistulas (8% of cases, can lead to hemorrhagic or ischemic stroke if untreated) 2
Venous Causes:
- Idiopathic intracranial hypertension/pseudotumor cerebri (second most common cause, particularly in young overweight women with headaches) 2
- Sigmoid sinus diverticulum or dehiscence (commonly associated with intracranial hypertension) 2
- Jugular bulb abnormalities (high-riding jugular bulb or dehiscence of sigmoid plate) 2
- Aberrant venous anatomy (persistent petrosquamosal sinus, abnormal condylar/mastoid emissary veins) 2
Structural/Neoplastic Causes:
- Paragangliomas and glomus tumors (16% of cases, appear as vascular retrotympanic masses on otoscopy) 2
- Adenomatous middle ear tumors 2
- Superior semicircular canal dehiscence (bony defect allowing transmission of vascular sounds) 2
Non-Pulsatile Tinnitus
Otologic Causes:
- Sensorineural hearing loss (most common identified cause) 3
- Cerumen impaction 4
- Tympanic membrane abnormalities 4
- Middle ear pathology 4
- Meniere disease 3
Neoplastic:
Other Causes:
- Temporomandibular joint dysfunction 1
- Eustachian tube dysfunction 1
- Ototoxic medications 5
- Head or cervical trauma 5
- Noise exposure 5
Psychological/Systemic:
Critical Diagnostic Approach
Step 1: Targeted History
Obtain specific tinnitus characteristics:
- Onset, duration, laterality (unilateral vs bilateral) 4
- Quality, pitch, loudness, pattern 4
- Pulsatile vs non-pulsatile 2
- Associated symptoms: hearing loss, vertigo, otalgia, otorrhea, neurological symptoms 4
- Medication history (ototoxic drugs) 5
- History of noise exposure, head trauma 5
Step 2: Physical Examination
- Otoscopic examination for cerumen, tympanic membrane abnormalities, vascular retrotympanic masses 4, 2
- Cranial nerve examination, especially CN VIII 4
- Auscultation of neck, periauricular region, temporal area for bruits if pulsatile 4
- Temporomandibular joint assessment 1
- Carotid/jugular compression maneuvers (relief suggests venous etiology or arterial dissection) 2
Step 3: Audiologic Testing
Obtain comprehensive audiologic examination (pure tone audiometry, speech audiometry, acoustic reflex testing) for: 7, 4
- Unilateral tinnitus (mandatory)
- Persistent tinnitus ≥6 months (mandatory)
- Associated hearing difficulties (mandatory)
- Consider for all tinnitus patients regardless of laterality or duration 4
Step 4: Imaging Decision Algorithm
Obtain imaging studies ONLY if one or more of the following are present: 7, 1
- Pulsatile tinnitus (nearly always requires imaging) 2
- Unilateral/asymmetric tinnitus 7, 1
- Asymmetric hearing loss 7, 1
- Focal neurological abnormalities 7, 1
Do NOT obtain imaging for: 7, 2
- Non-pulsatile, bilateral tinnitus without neurological symptoms
- Non-localizing tinnitus without red flags
Imaging Selection for Pulsatile Tinnitus:
First-line: High-resolution CT temporal bone (non-contrast) when suspecting: 2
- Paragangliomas, glomus tumors
- Jugular bulb abnormalities
- Superior semicircular canal dehiscence
- Aberrant vascular anatomy
First-line: CT angiography (CTA) head/neck with contrast when suspecting: 2
- Dural arteriovenous fistulas
- Arterial dissection
- Atherosclerotic carotid disease
- Sigmoid sinus diverticulum/dehiscence
- Arteriovenous malformations
Second-line: MRI with contrast and MRA reserved for: 2
- Cerebellopontine angle lesions (vestibular schwannoma)
- Negative CT/CTA with high clinical suspicion
- Contraindications to iodinated contrast
Red Flags Requiring Urgent Evaluation
Immediate escalation needed for: 1
- Sudden onset unilateral tinnitus with hearing loss
- Focal neurological deficits
- Pulsatile tinnitus (especially objective tinnitus audible to examiner) 2
- Severe anxiety or depression
- History of malignancy or recent trauma
- Vision changes (suggests intracranial hypertension) 2
Common Pitfalls to Avoid
- Missing dural AVF: Life-threatening cause requiring high index of suspicion; can present with isolated pulsatile tinnitus before catastrophic hemorrhage 2
- Dismissing pulsatile tinnitus as benign: Pulsatile tinnitus almost always requires imaging due to identifiable causes in >70% of cases 2
- Inadequate otoscopic examination: Can lead to delayed diagnosis of vascular retrotympanic masses (paragangliomas) 2
- Overlooking intracranial hypertension: Particularly in young, overweight women with headaches; can lead to vision loss if missed 2
- Unnecessary imaging for bilateral non-pulsatile tinnitus: Avoid routine imaging without red flags 7, 2
- Overlooking mild hearing loss: May benefit from amplification even if patient doesn't perceive hearing loss 1
Management Classification
Distinguish Bothersome vs Non-Bothersome Tinnitus
This distinction is mandatory as it determines intervention intensity 7, 1
Distinguish Recent Onset vs Persistent (≥6 months)
This classification prioritizes intervention and facilitates discussions about natural history 7, 1
For persistent bothersome tinnitus: