The role of vestibular function tests in nontuberculous mycobacterial otomastoiditis: A case report

Background: Nontuberculous mycobacteria (NTM), an extremely rare pathogen causing cervicofacial infections, may result in permanent hearing impairment or intracranial complications. Due to the lack of specific manifestations during the initial onset of NTM otomastoiditis, physicians may misdiagnose it as cholesteatoma or other common bacterial infections. Patient concerns: A 44-year-old male who complained of left-sided aural fullness, otalgia, and dizziness for 2 months. Diagnosis: The initial diagnosis was hypothesized to be cholesteatoma based on a whitish mass with mucoid discharge filling the entire outer ear canal on otoscopy and left-sided mixed hearing loss. However, NTM was identified by microbial culture at the 2-month follow-up after surgery. Interventions: The patient underwent a left-sided exploratory tympanotomy. Because NTM otomastoiditis was diagnosed, 3 weeks of starting therapies were administered with azithromycin (500 mg/day, oral administration), cefoxitin (3 g/day, intravenous drip), and amikacin (750 mg/day, intravenous drip). The maintenance therapies were azithromycin (500 mg/day, oral administration) and doxycycline (200 mg/day, oral administration) for 7 months. Outcomes: The patient's clinical condition improved initially after surgery, but the otomastoiditis gradually worsened, combined with subtle meningitis, 2 months after surgery. The external auditory canal became swollen and obstructed, making it difficult to monitor the treatment efficacy through otoscopy. Thus, we used regular vestibular function tests, including static posturography, cervical vestibular evoked myogenic potentials, and video Head Impulse Test, to assess recovery outcomes. After antibiotic treatment, the infectious symptoms subsided significantly, and there was no evidence of infection recurrence 7 months after treatment. Improvements in static posturography and cervical vestibular evoked myogenic potentials were compatible with the clinical manifestations, but video Head Impulse Test showed an unremarkable correlation. Lessons: The clinical condition of NTM otomastoiditis may be evaluated using vestibular tests if patients have symptoms of dizziness.