Sudden sensorineural hearing loss (SSNHL) can occur suddenly in one ear, and generally within three days, cause a 30+ dB hearing loss at three consecutive frequencies. The cause for this disorder is unclear, but research has indicated that viral infection, vascular compromise, and immunologic diseases could be key reasons for this hearing disorder.

Treatment of SSNHL remains controversial. Different approaches such as steroids, vasodilator, antiviral agents, diuretics, and low-salt diets have been suggested. Nevertheless, spontaneous recovery rate without treatment ranges from 30 to 60%, most resolving within two weeks after onset.

As a result of its anti-inflammatory effect, high-dosage systemic steroid therapy is currently the mainstay of the treatment for SSNHL. Despite oral or intravenous steroid therapy for two weeks, approximately 30-50% of patients show no response. Animal studies have found that intratympanic steroid injections, introducing steroids through the tympanic membrane, results in reduced systemic steroid toxicity and higher perilymph steroid level selectively. Past research has focused on use of these injections as a secondary-line therapy in SSNHL refractory cases. Other clinicians promote its use as first-line therapy in all SSNHL cases. Nevertheless, few controlled studies have been published comparing the results between intratympanic steroid treatment and other approaches.

A new study evaluates the effect of intratympanic steroid injections in patients with SSNHL after failure to respond to systemic steroid treatment. Patients who refused this regimen were used as controls in this research. The authors of “Intratympanic Steroids for Treatment of Sudden Hearing Loss After Failure of Intravenous Therapy,” are Guillermo Plaza, MD, PhD, from the Otolaryngology Department, Hospital de Fuenlabrada, and Carlos Herráiz, MD, PhD, with the Otolaryngology Department, Fundación Hospital Alcorcón, both in Madrid, Spain. Their findings were presented at the 110th Annual Meeting and OTO EXPO of the American Academy of Otolaryngology—Head and Neck Surgery Foundation, held September 17-20, 2006, at the Metro Toronto Convention Centre, Toronto, Canada.

This non-randomized prospective clinical trial showed that intratympanic methylprednisolone significantly improved the outcome of SSNHL after intravenous steroid treatment. As previously reported, intratympanic steroids actually are an effective and safe therapy in SSNHL cases that are refractory to standard treatment.

The researchers suggest that the number of injections, the type of steroid, and the most adequate doses must be defined in randomized prospective clinical trials. Also, these randomized studies will allow establishing an evidence-based treatment for idiopathic SSNHL. These trials should also evaluate outcomes after initial therapy for SSNHL comparing steroids that are administrated systemically or by intratympanic injections.

[SOURCE: Newswise, September 2006]