Intratympanic Dexamethasone Injection as Salvage Therapy for Refractory Bilateral Sudden Sensorineural Hearing Loss in Clinically Presumed Waldenström Macroglobulinemia: A Case Report and Literature Review.

Bilateral sudden sensorineural hearing loss (BSSHL) is an uncommon otologic emergency that may occur as the initial manifestation of relapsed B-cell non-Hodgkin lymphoma complicated by hyperviscosity syndrome (HVS). Systemic Bruton tyrosine kinase (BTK) inhibition can reduce IgM levels but may be insufficient to reverse cochlear dysfunction. We present a 74-year-old woman with a history of small B-cell non-Hodgkin lymphoma who developed simultaneous bilateral profound sudden hearing loss secondary to clinically presumed Waldenström macroglobulinemia (WM). Serum IgM peaked at 53.21 g/L, and fundoscopic examination showed typical hyperviscosity retinopathy. Despite four weeks of treatment with zanubrutinib, hearing showed no improvement. Bilateral intratympanic dexamethasone (IT-Dex) injections (5 mg daily for 6 consecutive days) were administered as salvage therapy.The patient began to perceive sound on day 3 and showed significant hearing improvement by day 6. Pure-tone average thresholds improved by 15 dB in the right ear and 20 dB in the left ear. This case demonstrates that IT-Dex injection is an effective salvage intervention for refractory HVS-related BSSHL that is unresponsive to systemic BTK inhibitor therapy. Multidisciplinary collaboration between otolaryngologists and hematologists is essential for timely diagnosis and intervention.