NEW YORK (Reuters Health) – For patients with Mיniטre's disease where vertigo is resistant to other therapies, intratympanic gentamicin therapy may relieve symptoms, Loyola University of Chicago investigators report.
Dr. John P. Leonetti told Reuters Health that the intratympanic injections take advantage of gentamicin's ototoxicity to create a "chemical ablation of the balance system in the affected ear," he explained.
"The gentamicin liquid is instilled into the middle ear, from where it is absorbed into the inner ear through the round window membrane," he continued. "It's not curing the vertigo. We're paralyzing the balance system completely in the affected ear, because the brain works better if it is using the normal balance system in the good ear only and no balance system in the affected ear."
As they report in the February issue of Otolaryngology-Head and Neck Surgery, Dr. Leonetti and Dr. Sam J. Marzo identified 68 patients with Mיniטre's disease treated at their clinic between 1999 and 2000. After failing medical therapy, they were all treated with endolymphatic sac decompression.
After endolymphatic sac decompression was performed, six patients experienced recurrent or persistent vertigo. Four were treated with a low sodium diet, diuretics, and vestibular suppressants, which failed to relieve symptoms after 3 to 6 months.
These four patients were given 3 or 4 weekly intratympanic injections of gentamicin, which relieved symptoms in three patients. The only patient who did not respond had also experienced no improvement following the endolymphatic sac procedure. None of the patients developed permanent hearing loss due to the injections.
Drs. Marzo and Leonetti note that if this treatment is successful, the patient can forgo the craniotomy required for vestibular neurectomy. However, they point out, the injections have a lower success rate and a higher incidence of hearing loss than does the neurectomy procedure.
The two otolaryngologists report that they have used intratympanic gentamicin to successfully treat patients with persistent vertigo following stapedectomy, perilymphatic fistula, and after vestibular neurectomy.
"Gentamicin injections are also of potential use in patients with benign postural vertigo, balance problems related to trauma, postoperative dizziness after the removal of tumors, and for those who are prone to virus infections of the inner ear," Dr. Leonetti added.