Sudden hearing loss isn’t the only condition that responds to intratympanic (IT) therapy (see "Optimal Usage of Intratympanic Drug Therapy for Sudden Hearing Loss Unclear"). This novel drug delivery method is also effective in easing the vertigo that characterizes Ménière’s disease—a finding that is not surprising given the parallels between the two conditions.
The most fundamental link between Ménière’s and sudden hearing loss is etiology: Both conditions are caused, to varying degrees, by a malfunction of the cochlea and vestibular system; both conditions can fluctuate, making diagnosis and treatment assessments a moving target; and both disorders respond to IT steroid therapy, although for Ménière’s, gentamicin has gained traction due to the aminoglycoside’s ablative effects on vestibular hair cells that are dysfunctional in patients with the balance disorder.
Another parallel between Ménière’s disease and sudden hearing loss is the lack of consensus on the best way to treat the condition. For example, a recent Cochrane review stated that “an effective evidence-based therapy has never been established” for Ménière’s disease (Cochrane Database Syst Rev. 2011;(3):CD008234). But, in reviewing the recent literature on IT gentamicin, the reviewers found two studies that met their main inclusion criteria of being placebo controlled and randomized. Both studies showed a significant reduction in vertigo complaints when compared with placebo, the authors noted. But in one of the trials, 25 percent of patients experienced some hearing loss as a result of gentamicin therapy.
David Haynes, MD, professor in the department of otolaryngology/The Otology Group of Vanderbilt, in Nashville, said the finding of hearing loss is not surprising. Although gentamicin tends to be more vestibulotoxic than ototoxic, “the drug definitely can be ototoxic,” he said. “So I usually try patients on at least a week of systemic medications and [non-drug] interventions to see how they progress before giving them gentamicin—especially if they have a good amount of residual hearing, which you really want to protect.”
In cases in which hearing is present, “I am reluctant to use intratympanic gentamicin unless the patient is really miserable,” Dr. Haynes added. “In fact, I probably use it less than 10 times a year.”
Richard K. Gurgel, MD, assistant professor, division of otolaryngology-head and neck surgery at the University of Utah Health Care in Salt Lake City, agreed that IT gentamicin is usually not a good first-line choice. In fact, “it should be reserved for someone who has failed medical therapy,” he said. That might include a low-sodium diet, he noted, because there is evidence to suggest that Ménière’s is partly caused by a salt and fluid imbalance in the inner ear. Thus, a diuretic may be another first-line option, he said.
It also is important to rule out any other causes of dizziness and nerve-related or inner ear hearing loss before jumping to more aggressive therapy with IT medications, Dr. Gurgel said. “We do that by obtaining a baseline MRI to make sure the patient doesn’t have a tumor or other structural anomaly that could be the cause of their balance problems,” he said.
Once drug therapy is considered, Dr. Gurgel noted, the frequency of symptoms is an important factor. “If someone is having very active symptoms, IT steroids can help calm down a flare-up,” he said. “But for long-term control, studies have shown that gentamicin is more effective.” In one recent trial of long-term IT gentamicin treatments, the overall rate of successful vertigo control was 92.9 percent at two years of follow-up and 85.7 percent at an average follow-up of 10 years (Acta Otolaryngol. 2009;129:1420-1424).
As with sudden hearing loss, however, the dosage regimens used to treat Ménière’s disease vary considerably both in practice and in the literature, “so there’s not too much guidance there,” Dr. Gurgel said. “We tend to use 40 mg/mL in a single injection, to start.” The difficult question, he pointed out, is when to stop therapy if there is no appreciable response. “There can be diminished effectiveness after two or three injections, although for some patients, more may be warranted.” If there’s no improvement after diet and lifestyle changes, medical therapy and intratympanic injections, he added, “then surgical interventions may be considered.”