Treatment of sudden deafness: carbon dioxide and oxygen inhalation and steroids

Steroids for idiopathic sudden sensorineural hearing loss

BACKGROUND

This is an update of a Cochrane review first published in The Cochrane Library in Issue 1, 2006 and previously updated in 2009.Idiopathic sudden sensorineural hearing loss (ISSHL) is a clinical diagnosis characterised by a sudden deafness of cochlear or retrocochlear origin in the absence of a clear precipitating cause. Steroids are commonly prescribed to treat this condition. There is no consensus on their effectiveness.

OBJECTIVES

To determine whether steroids in the treatment of ISSHL a) improve hearing (primary) and b) reduce tinnitus (secondary).To determine the incidence of significant side effects from the medication.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 22 April 2013.

SELECTION CRITERIA

We identified all randomised controlled trials (with or without blinding) in which steroids were evaluated in comparison with either no treatment or a placebo. We considered trials including the use of steroids in combination with another treatment if the comparison control group also received the same other treatment. The two authors reviewed the full-text articles of all the retrieved trials of possible relevance and applied the inclusion criteria independently.

DATA COLLECTION AND ANALYSIS

We graded trials for risk of bias using the Cochrane approach. The data extraction was performed in a standardised manner by one author and rechecked by the other author. Where necessary we contacted investigators to obtain the missing information. Meta-analysis was neither possible nor considered appropriate because of the heterogeneity of the populations studied and the differences in steroid formulations, dosages and duration of treatment. We analysed and reported the quality of the results of each study individually. A narrative overview of the results is presented.

MAIN RESULTS

Only three trials, involving 267 participants, satisfied the inclusion criteria and all three studies were at high risk of bias. One trial showed a lack of effect of oral steroids in improving hearing compared with the placebo control group. The second trial showed a significant improvement of hearing in 61% of the patients receiving oral steroid and in only 32% of the patients from the control group (combination of placebo-treated group and untreated control group). The third trial also showed a lack of effect of oral steroids in improving hearing compared with the placebo control. However, this trial did not follow strict inclusion criteria for participant selection and analysis of data was limited by significant exclusion of participants from the final analysis and lack of participant compliance to the treatment protocol. No clear evidence was presented in two trials about any harmful side effects of the steroids. Only one study declared that no patients suffered from adverse effects of the steroid treatment.

AUTHORS' CONCLUSIONS

The value of steroids in the treatment of idiopathic sudden sensorineural hearing loss remains unclear since the evidence obtained from randomised controlled trials is contradictory in outcome, in part because the studies are based upon too small a number of patients.

Vasodilators and vasoactive substances for idiopathic sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) is sudden hearing loss where clinical assessment fails to reveal a cause. The most widely used therapeutic agents for ISSHL are antivirals, steroids, hyperbaric oxygen, vasodilators and rheological/vasoactive substances. There is currently conflicting evidence for vasodilator and vasoactive substances in the treatment of ISSHL.

OBJECTIVES

1. To determine the effectiveness of vasodilators and other vasoactive substances in improving hearing in patients with ISSHL. 2. To determine the adverse effects of these medications.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was 16 September 2008.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of vasodilators/vasoactive substance versus placebo in the treatment of ISSHL. Trials were assessed for methodological quality.

DATA COLLECTION AND ANALYSIS

The authors assessed trials and extracted data independently. We contacted investigators to obtain additional information where necessary. Meta-analysis was neither possible nor considered appropriate due to the differences in the type of vasodilators used, dosage and duration of treatment. The quality and the result of each study was analysed and reported individually.

MAIN RESULTS

Only three trials, involving 189 participants, satisfied the inclusion criteria and these were of low methodological quality. One study showed a significant difference in hearing recovery in the vasodilator group (carbogen combined with a course of several other drugs) compared to the control group (a course of several other drugs alone). Another study only showed a significant improvement in higher frequencies in the vasodilator group (prostaglandin E1 + steroid) compared with the control group (placebo and steroid), no difference having been shown in overall hearing gain. In the third study the vasodilator group (naftidrofuryl and low-molecular weight dextran) showed an improvement only in lower frequencies over the control group (placebo and low-molecular weight dextran).Two of the studies reported adverse effects from vasodilator treatment, whereas there was no mention of any side effects in the third. Five patients in one study developed a sensation of heaviness in the head which settled spontaneously and did not interfere with treatment. In the other study one patient developed an allergic reaction and had to be excluded from the study.

AUTHORS' CONCLUSIONS

The effectiveness of vasodilators in the treatment of ISSHL remains unproven. The included studies were of relatively poor quality and the number of patients included was small. Moreover, there were differences in the type, dosage and duration of vasodilator used in each study. Due to the degree of heterogeneity the results could not be combined to reach a conclusion.

Steroids for idiopathic sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) is a clinical diagnosis characterised by a sudden deafness of cochlear or retrocochlear origin in the absence of a clear precipitating cause. Steroids are commonly prescribed to treat this condition. There is no consensus on their effectiveness.

OBJECTIVES

To determine the effectiveness and the side-effect profile of steroids in the treatment of idiopathic sudden sensorineural hearing loss.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to December 2004) and EMBASE (1974 to December 2004). Reference lists of all trials were also manually searched.

SELECTION CRITERIA

We identified all randomised controlled trials (with or without blinding) in which steroids were evaluated in comparison with either no treatment or a placebo. Trials including the use of steroids in combination with another treatment were considered if the comparison control group also received the same other treatment. The full text articles of all the retrieved trials of possible relevance were reviewed by the two authors and the inclusion criteria applied independently. Any differences in opinion about which studies to include in the reviews were resolved by discussion.

DATA COLLECTION AND ANALYSIS

Trials were graded for methodological quality using the Cochrane approach. The data extraction was performed in a standardised manner by one author and rechecked by the other author, and where necessary investigators were contacted to obtain the missing information. Meta-analysis was neither possible nor considered appropriate because of the heterogeneity of the populations studied, the differences in steroid formulations, dosages and duration of the treatment. The quality of the result of each study was analysed and reported individually. A narrative overview of the result is presented.

MAIN RESULTS

Only two trials satisfied the inclusion criteria and both were of low methodological quality. One trial showed a lack of effect of oral steroids in hearing improvement compared with the placebo control group. The other trial showed a significant improvement of hearing in 61% of the patients receiving oral steroid and in only 32% of the patients from the control group (combination of placebo treated group and untreated control group). There was no clear evidence presented in the former study about any harmful side effects of the steroids. The latter study declared that no patients suffered from adverse effects from the steroid treatment.

AUTHORS' CONCLUSIONS

The value of steroids in the treatment of idiopathic sudden sensorineural hearing loss remains unclear since the evidence obtained from randomised controlled trials are contradictory in outcome, in part because the studies are based upon too small a number of patients.