Bilateral Pulsatile Tinnitus When Laying Down: Causes and Evaluation
Primary Recommendation
Bilateral pulsatile tinnitus when laying down most commonly indicates idiopathic intracranial hypertension (IIH) or venous sinus abnormalities, particularly in patients with hypertension, and requires urgent vascular imaging with CT angiography (CTA) of the head and neck as first-line evaluation. 1, 2
Critical Diagnostic Context
While bilateral presentation is less common than unilateral pulsatile tinnitus, it still demands comprehensive imaging evaluation because identifiable structural or vascular causes exist in over 70% of pulsatile tinnitus cases overall. 1, 2 The positional nature (occurring when laying down) is particularly suggestive of venous pathology or intracranial pressure changes. 2
Most Likely Causes in Bilateral Presentation
Venous and Intracranial Pressure Etiologies
Idiopathic intracranial hypertension (IIH) is the second most common cause of pulsatile tinnitus overall and frequently presents bilaterally, particularly in young overweight women with headaches. 2, 3 This condition can lead to vision loss if missed. 1
Sigmoid sinus diverticulum or dehiscence is commonly associated with intracranial hypertension and can cause bilateral symptoms. 2
Jugular bulb abnormalities including high-riding jugular bulb or dehiscence of the sigmoid plate can produce bilateral pulsatile tinnitus. 2
Aberrant venous anatomy including persistent petrosquamosal sinus and abnormal condylar/mastoid emissary veins may cause bilateral symptoms. 2
Arterial Causes (Can Present Bilaterally)
Atherosclerotic carotid artery disease is the single most frequent cause of pulsatile tinnitus at 17.5% of cases, resulting from turbulent flow, and can affect both sides in patients with hypertension. 1, 2, 3
Arterial dissection is potentially life-threatening and requires urgent identification, though typically unilateral. 1, 2
Systemic and Metabolic Causes
Hypertension itself can cause bilateral pulsatile tinnitus through increased vascular pulsatility and turbulent flow. 3
High cardiac output states including hyperthyroidism, anemia, or cardiac arrhythmias can produce bilateral pulsatile tinnitus. 3, 4
Mandatory First-Line Imaging Strategy
Order CT angiography (CTA) of the head and neck with contrast as the initial study when suspecting venous sinus abnormalities, sigmoid sinus diverticulum/dehiscence, atherosclerotic carotid disease, or arteriovenous malformations. 1, 2 A mixed arterial-venous phase (20-25 seconds post-contrast) captures both arterial and venous pathology in a single acquisition. 2
Alternatively, order high-resolution CT temporal bone (non-contrast) if the clinical presentation suggests jugular bulb abnormalities, superior semicircular canal dehiscence, or aberrant vascular anatomy. 1, 2
CTA source images can be reconstructed to create dedicated temporal bone CT images without additional radiation exposure. 2
When to Escalate Imaging
If initial CTA is negative but clinical suspicion remains high (particularly with vision changes, severe headaches, or neurologic symptoms), proceed to MRI brain with contrast and MR venography (MRV) to evaluate for venous sinus abnormalities, subtle vascular malformations, or cerebellopontine angle lesions. 1, 2
Life-Threatening Causes That Cannot Be Missed
Dural arteriovenous fistulas (AVF) account for 8% of pulsatile tinnitus cases and can lead to catastrophic hemorrhage or ischemic stroke if untreated—maintain extremely high index of suspicion even with bilateral presentation. 1, 2
Arterial dissection requires urgent anticoagulation or endovascular intervention. 1
IIH with papilledema can cause permanent vision loss if treatment is delayed. 1, 2
Clinical Examination Pearls
Perform jugular/carotid compression test: Relief of pulsatile tinnitus upon compression suggests venous etiology (sigmoid sinus abnormalities, jugular bulb variants) or arterial dissection. 1, 2
Otoscopic examination is mandatory to identify vascular retrotympanic masses (paragangliomas), though these typically present unilaterally. 1, 2
Assess for papilledema on fundoscopic exam, particularly in young overweight women, as this indicates IIH requiring urgent treatment. 2
Check blood pressure, as uncontrolled hypertension can both cause and exacerbate pulsatile tinnitus. 3
Critical Pitfalls to Avoid
Never dismiss bilateral pulsatile tinnitus as benign without imaging—the bilateral nature does not exclude dangerous pathology. 1, 2
Do not confuse this with bilateral nonpulsatile tinnitus, which typically does not require imaging per ACR guidelines. 5 The pulsatile quality fundamentally changes the diagnostic approach. 2
Inadequate otoscopic examination leads to delayed diagnosis of paragangliomas and other vascular masses. 1, 2
Missing IIH in young overweight women with headaches can result in irreversible vision loss. 1, 2
Ordering MRV alone is insufficient—CT temporal bone or CTA head and neck should be the initial study. 2