In a patient with polycythemia vera presenting with unilateral tinnitus, what is the appropriate diagnostic work‑up and immediate management?

Unilateral Tinnitus in Polycythemia Vera: Diagnostic Work-Up and Management

In a patient with polycythemia vera presenting with unilateral tinnitus, immediately determine whether the tinnitus is pulsatile or non-pulsatile through focused history, then proceed directly to imaging—either high-resolution CT temporal bone or CT angiography of the head and neck—because unilateral tinnitus has identifiable structural or vascular pathology in over 70% of cases, and PV's hyperviscosity and thrombotic risk create additional vascular complications that require urgent exclusion. 1, 2, 3

Immediate Clinical Characterization

Determine the exact nature of the tinnitus:

• Ask if the sound is synchronous with the heartbeat (pulsatile) versus continuous buzzing or ringing (non-pulsatile), as this fundamentally changes the diagnostic pathway and urgency. 1, 2, 3

• Assess for associated symptoms including headache, vision changes, focal neurologic deficits, hearing loss, or vertigo—any of these red flags mandate immediate imaging. 1

• Perform comprehensive otoscopic examination to identify vascular retrotympanic masses (paragangliomas appear as red pulsatile lesions behind the tympanic membrane), cerumen impaction, or middle ear effusion. 2, 3

PV-Specific Vascular Considerations

Polycythemia vera creates unique thrombotic and hyperviscosity risks:

• PV patients have 16% arterial thrombosis and 7% venous thrombosis rates at or before diagnosis, with unusual sites like splanchnic veins commonly involved. 4

• Hyperviscosity from elevated hematocrit can cause microcirculatory symptoms including tinnitus, transient visual changes (14% of PV patients), and other neurologic manifestations. 5, 4

• Extreme thrombocytosis (≥1000 × 10⁹/L) in PV can cause acquired von Willebrand disease, increasing bleeding risk alongside thrombotic risk. 4

First-Line Imaging Strategy

For pulsatile tinnitus in PV:

• Order CT angiography (CTA) of head and neck with mixed arterial-venous phase contrast (20-25 seconds post-contrast) as the first-line study to simultaneously evaluate arterial causes (atherosclerotic disease, dissection, dural arteriovenous fistulas, AVMs) and venous causes (sigmoid sinus abnormalities, jugular bulb variants). 1, 2, 3

• CTA is critical in PV because it detects life-threatening vascular lesions—dural arteriovenous fistulas account for 8% of pulsatile tinnitus and can cause hemorrhagic stroke if missed, while arterial dissection is immediately life-threatening. 3

For non-pulsatile unilateral tinnitus in PV:

• Order MRI of head and internal auditory canals without and with IV contrast to exclude retrocochlear lesions, particularly vestibular schwannomas (present in 63-75% of patients with unilateral tinnitus) and cerebellopontine angle tumors. 1, 2

• If MRI is contraindicated, order high-resolution CT temporal bone with contrast, though small internal auditory canal lesions may be missed. 1

If otoscopy reveals a vascular retrotympanic mass:

• Order high-resolution CT temporal bone without contrast to evaluate for paragangliomas (glomus tympanicum/jugulotympanicum), adenomatous middle ear tumors, jugular bulb abnormalities, superior semicircular canal dehiscence, or aberrant vascular anatomy. 1, 2, 3

Mandatory Audiologic Testing

• Obtain comprehensive audiologic examination within 4 weeks including pure-tone audiometry, speech audiometry, and acoustic reflex testing for any unilateral tinnitus, as asymmetric hearing loss changes the diagnostic algorithm and treatment approach. 1, 2, 6

• Do not delay audiometry even if the patient denies hearing difficulties, as mild hearing loss amenable to amplification is frequently missed without formal testing. 3, 6

Immediate PV Management Alongside Tinnitus Work-Up

Optimize hematocrit control urgently:

• Verify hematocrit is maintained below 45% through therapeutic phlebotomy, as elevated hematocrit directly increases thrombotic risk and hyperviscosity symptoms including tinnitus. 5, 4

• Ensure aspirin therapy (81 mg once or twice daily) is prescribed unless contraindications exist, particularly if platelet count is extremely elevated (≥1000 × 10⁹/L) causing acquired von Willebrand disease. 5, 4

• Consider cytoreductive therapy intensification with hydroxyurea or interferon if the patient is high-risk (age >60 years or prior thrombosis) and not already on adequate cytoreduction. 5, 4

Second-Line Imaging if Initial Studies Negative

• If CTA or initial imaging is negative but clinical suspicion remains high, proceed to MRI brain with contrast combined with MR angiography and MR venography to assess for subtle vascular malformations, detailed venous sinus anatomy, cerebellopontine angle lesions, and signs of intracranial hypertension. 3

• Time-resolved gadolinium-enhanced MRA with arterial spin-labeling provides high sensitivity for detecting dural arteriovenous fistulas that may be missed on standard CTA. 3

Critical Pitfalls to Avoid

• Never dismiss unilateral tinnitus in PV as benign hyperviscosity without imaging, as structural vascular pathology is identifiable in >70% of unilateral tinnitus cases, and PV's prothrombotic state increases risk of arterial dissection, dural AVF, and venous sinus thrombosis. 2, 3

• Do not wait for tinnitus to become bilateral or persistent before ordering imaging—unilateral presentation is itself an indication for immediate imaging regardless of duration. 1, 2

• Avoid ordering MRV alone for pulsatile tinnitus evaluation, as it is insufficient; CT temporal bone or CTA head and neck should be the initial study. 3

• Do not overlook extreme thrombocytosis (≥1000 × 10⁹/L) in PV patients, as this paradoxically increases bleeding risk through acquired von Willebrand disease and may contraindicate aspirin. 4

• Never attribute tinnitus solely to PV without excluding structural causes, as vestibular schwannomas, dural AVFs, and other treatable lesions require specific interventions beyond PV management. 1, 2, 3