Μπίμπας Αθανάσιος, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ, Επιβλέπων
Κατσουγιάννη Ελένη-Κλεάνθη, Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Κυροδήμος Ευθύμιος, Επίκουρος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Acute acoustic trauma is the clinical condition of immediate persistent hearing loss after exposure to an impulse and high-intensity noise. There are no definitive guidelines for the treatment of acute noise-induced hearing loss. Glucocorticoids have been long used for therapy of inner ear disease and seem to comprise the only potentially beneficial option for the patient with AAT, since steroid hormones act in several pathophysiological pathways ameliorating cochlear damage induced by noise overexposure. The optimal management of steroid administration, considering the regimen choice, dosage, route, duration and onset of therapy are not well established. The aim of the present study is to critically appraise the role of corticosteroids in AAT treatment.
Methods: A list of predefined terms was used to electronically search the Medline and Cochrane Library databases. Main inclusion criteria were English language; publication during the 2005-2019 period; noise-induced hearing loss due to AAT and steroid treatment; clinical and preclinical studies.
Studies on noise-induced hearing loss due to chronic exposure to noise, acute noise-induced hearing loss involving middle ear pathology, studies on combination of steroids with other, non pharmacological therapies for treatment, such as hyperbaric oxygen administration (HBO), on preventive steroid administration, studies without details of treatment or outcome and articles for which full texts were not obtainable were excluded.
After systematic search, 247 articles were identified. 232 were excluded (124 after de-duplication, 99 due to irrelevancy with the disease and treatment, 10 due to not fulfilling the eligibility criteria). In total, 15 studies were included in the qualitative synthesis; (6 clinical, 9 preclinical). Results of each study were presented separately, assessing the overall efficacy of treatment and all the other factors that might influence the outcome.
The main points of interest from the available clinical and preclinical studies are:
1. There is a lack of placebo-controlled clinical trial, although clinical studies presented a possible beneficial effect of steroids on AAT treatment. Support was provided by the majority of preclinical studies.
2. There is no evidence of difference in efficacy between various steroid agents. Most common regimens are prednisolone 60mg administered orally and dexamethasone 5mg/ml transtympanically
3. Prolonged treatment duration might further improve outcomes.
4. Early treatment onset seems to be crucial. Evidence suggests that early initiation of steroids significantly improves the final hearing recovery, especially when treatment is offered within an hour from the noise exposure.
5. Route of administration seems to not affect efficacy, however combination of systemic and intratympanic administration proved to be superior over the conventional systemic treatment.
Limitations in the included studies were mainly the absence of control group in clinical studies, which would produce definite and quantitative outcomes, the small size of the samples and the difficulty to determine the noise level and characteristics inducing AAT..
There is evidence in support of the efficacy of steroid therapy in AAT. High dosage, immediate onset of treatment, combined oral and intratympanic administration may result in the optimal outcome for hearing recovery. Yet, more clinical trials with larger samples are required so that guidelines for AAT treatment can be established.
Acoustic trauma, Acute noise-induced hearing loss, Corticosteroid, Cortisone, Steroid, Treatment