How do you differentiate between pulsatile and non-pulsatile tinnitus (Temporary Threshold Shift)?

Differentiating Pulsatile from Non-Pulsatile Tinnitus

Pulsatile tinnitus is rhythmic and synchronous with the patient's heartbeat, while non-pulsatile tinnitus is a continuous buzzing or ringing sound without cardiac synchronization. 1, 2

Key Clinical Distinctions

Pulsatile Tinnitus Characteristics

• The sound is rhythmic and beats in time with the patient's pulse, which can be confirmed by having the patient count their pulse while listening to the tinnitus 2, 3
• The patient describes hearing a "whooshing," "thumping," or "pulsing" sound that matches their heartbeat 1
• Pulsatile tinnitus can be further classified as objective (audible to the examiner with a stethoscope) or subjective (only the patient hears it), with objective tinnitus strongly suggesting vascular pathology requiring immediate workup 1
• The sound may be relieved by carotid or jugular compression, which suggests venous etiology (sigmoid sinus abnormalities, jugular bulb variants) or arterial dissection 1, 4

Non-Pulsatile Tinnitus Characteristics

• The sound is continuous, steady, and does not vary with the cardiac cycle 2
• Patients typically describe ringing, buzzing, hissing, or humming sounds that are constant 2
• The sound has no relationship to heartbeat or respiration 5

Critical Diagnostic Implications

Why This Distinction Matters

• Pulsatile tinnitus almost always requires imaging evaluation because it indicates an underlying vascular or structural abnormality in over 70% of cases, while bilateral non-pulsatile tinnitus without localizing features typically does not require imaging 1, 4
• Missing life-threatening causes like dural arteriovenous fistula or arterial dissection in pulsatile tinnitus can result in catastrophic hemorrhage or stroke 1
• The most common causes of pulsatile tinnitus include atherosclerotic carotid artery disease (17.5%), paragangliomas (16%), and idiopathic intracranial hypertension (second most common) 1

Unilateral vs Bilateral Presentation

• Unilateral pulsatile tinnitus has a higher likelihood of identifiable structural or vascular cause compared to bilateral 1, 6
• Bilateral pulsatile tinnitus should prompt evaluation for systemic conditions causing increased cardiac output 7
• Unilateral presentation requires focused imaging studies to exclude organic etiologies at cervical and cranial levels 7

Physical Examination Maneuvers

Essential Bedside Tests

• Perform otoscopy to identify vascular retrotympanic masses (paragangliomas appear as red pulsatile masses behind the tympanic membrane) 1, 6
• Apply gentle pressure to the ipsilateral carotid artery or jugular vein while the patient reports whether the tinnitus changes 4, 3
• Auscultate over the periauricular area, mastoid, orbit, and neck with a stethoscope to detect objective pulsatile tinnitus 3
• Perform head positioning tests to assess whether positional changes affect the tinnitus 3

Common Pitfalls to Avoid

• Dismissing pulsatile tinnitus as benign is a critical error, as it requires imaging evaluation in nearly all cases due to identifiable causes in >70% of cases 1
• Inadequate otoscopic examination can lead to delayed diagnosis of vascular retrotympanic masses (paragangliomas), resulting in inappropriate imaging selection 1
• Missing dural arteriovenous fistula is life-threatening, as it can present with isolated pulsatile tinnitus before catastrophic hemorrhage 1, 8
• Overlooking intracranial hypertension, particularly in young overweight women with headaches, can lead to permanent vision loss 1