Sudden sensori-neural hearing loss treated by carbon dioxide and oxygen inhalation. A preliminary study

Roid Rage: Historical Perspective on the Emergence of Oral Steroids as a Treatment of Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVES

To review the historical circumstances that led to the emergence of corticosteroid therapy for idiopathic sudden sensorineural hearing loss (ISSNHL) and to discuss how this history has influenced current perspectives on the condition.

METHODS

PubMed and Google scholar were used to identify articles of ISSNHL and oral corticoid steroid use. Historical articles accessed through our institutional medical library were also reviewed.

RESULTS

The use oral corticosteroids as a treatment for ISSNHL was seemingly influenced by three key historical circumstances that, together, provided the substrate for the treatment's use in ISSNHL. First, ISSNHL was a frustrating condition with uncertainty regarding its etiology and few reliable treatment options. Second, the discovery of corticosteroids was awarded the Nobel Prize in 1950, which led to widespread application of this therapy. Third historical circumstance was the evolution and emergence of more rigorous methodological study designs in clinical research. In 1980, these events culminated in a double-blind study evaluating the effectiveness of oral steroids for treatment of ISSNHL. Interestingly, this study is often misrepresented as a randomized controlled trial, which ultimately contributed to adoption of a new standard for treatment in ISSNHL. Research subsequent to these historical events has challenged the notion of corticosteroids as a gold standard but has not altered the historically established paradigm of corticosteroid treatment.

CONCLUSIONS

The use of steroids as a treatment for ISSNHL evolved from our specialty's need to address a complex condition, a novel therapeutic discovery, and a landmark study that met emerging methodological standards. Despite these strong historical foundations, ISSNHL remains a condition with an unknown etiology and the therapeutic value of corticosteroids remains unpredictable despite their gold standard label.

Effectiveness of hyperbaric oxygen therapy in management of sudden hearing loss

Objective:

To evaluate the effectiveness of hyperbaric oxygen therapy in the management of sudden hearing loss.

Study design:

Patients with sudden hearing loss were divided into study and control groups. The 36 patients in the study group were treated with hyperbaric oxygen therapy in addition to standard medical therapy, whereas the 21 patients in the control group were treated with only standard medical therapy.

Subjects and methods:

Both groups were treated with standard therapy, comprising prednisolone starting at a dose of 1 mg/kg and reducing over three weeks. Patients in the study group received hyperbaric oxygen therapy in addition to standard drug therapy.

Results:

Success rates were 78.95 per cent in the study group and 71.30 per cent in the control group. However, this difference was not statistically significant (p > 0.05).

Conclusions:

Considering the cost of hyperbaric oxygen therapy and its inconvenience to patients, this treatment should only be considered in patients suffering sudden hearing loss if there are contraindications to standard medical treatment.

Sudden Hypoacusis Treated with Hyperbaric Oxygen Therapy: A Controlled Study

The term sudden hypoacusis describes a hearing loss of rapid onset and unknown origin that can progress to severe deafness. Of the many therapeutic protocols that have been proposed for treating sudden hypoacusis, hyperbaric oxygen therapy (HOT) plays a leading role. We studied 50 patients who had been referred to our ENT unit within 48 hours of the onset of sudden hypoacusis. We randomly assigned 30 of these patients to undergo once-daily administration of HOT for 10 days; the other 20 patients were treated for 10 days with an intravenous vasodilator. Response to therapy in all patients was evaluated by calculating the mean hearing threshold at frequencies between 500 and 4, 000 Hz and by assessing liminal tonal audiometry results recorded at baseline and 10 days after the cessation of treatment. These results, plus the findings of other audiologic and otoneurologic examinations, revealed that the patients in the HOT group experienced a significantly greater response to treatment than did those in the vasodilator group, regardless of age and sex variables. Significantly more patients in the HOT group experienced a good or significant response. In both groups, patients with pantonal hypoacusis responded significantly better than did those with a milder condition. Based on our findings, coupled with the fact that oxygen therapy is well tolerated and produces no side effects, we conclude that HOT should be considered the preferred treatment for patients with sudden hypoacusis.

The influence of carbogen on susceptibility to TTS

A group of 20 male subjects were exposed to noise in each of four separate conditions. In two conditions they inhaled carbogen (95% oxygen, 5% carbon-dioxide). In two others they inhaled compressed air. In two conditions they were exposed to noise after inhalation and in two they were exposed to noise during the inhalation. The results indicated that carbogen inhalation reduced the magnitude of TTS but only in the 'During' condition.

Evaluation of a "shotgun" regimen for sudden hearing loss

One hundred nine patients with idiopathic sudden hearing loss were treated with a "shotgun" regimen that included dextran, histamine, Hypaque, diuretics, steroids, vasodilators, and carbogen inhalation. Thirty-three patients received the entire protocol and 76 patients received most, but not all, of the protocol drugs. Some improvement of hearing (greater than 10 dB in pure-tone average) was seen in 52% of patients treated with the complete protocol and in 54% of patients who received the partial protocol. All patients were analyzed for potential prognostic indicators. Patients with thresholds at 8000 Hz better than at 4000 Hz fared better than the group as a whole. Vertigo at the time of onset of hearing loss was a sign of poor prognosis. There was no correlation between hearing improvement and the age of the patient or the sedimentation rate. Most importantly, there was no statistically significant difference in outcome between patients treated with the complete protocol and those who received only part of the protocol. Furthermore, when the effect of each drug was examined individually, there was no significant difference between those patients receiving and not receiving treatment. The results suggest that this "shotgun" approach for treatment of sudden hearing loss offers no better outcome than is reported in the literature for spontaneous recovery.

Acute bilateral total deafness complicating mumps

While it is well known that mumps is a potential cause of deafness, it is not generally appreciated that it can produce total deafness. The damage is usually unilateral but bilateral disease has been recorded. A case is presented of severe bilateral hearing loss during a mumps epidemic in which, in spite of intensive conventional as well as lesser known therapy, no improvement occurred. In the absence of a successful therapeutic regime it is clearly advisable to intensify immunization in non-developed countries.

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

The results of treating 86 patients with sudden deafness are reviewed in this paper. They were treated with intravenous ATP-2Na, Vitamin B1, B6, B12 and C, stellate ganglion block, peroral steroids, cyclandelate and Kallidinogenase. Fifty-one of 86 patients were additionally treated with carbon dioxide and oxygen inhalation. The first 35 patients (no gas inhalation group) and the latter 51 patients (gas inhalation group) were compared with each other concerning hearing improvement, and recovery rate associated with age of the patients, untreated period and effect of steroids. There was no statistical difference between the two groups with regard to these parameters.

Management of sudden deafness

Measurements according to the polarographic principle in cats have shown that the factors influencing the perilymphatic oxygen tension are the arterial PCO2, the arterial PO2, and the systemic blood pressure. In patients with sudden deafness, the oxygen supply to the vestibular tissues is significantly reduced but the response to carbogen is still possible. The vasodilation induced by carbogen in sudden deafness is not accompanied by a reduction (stealing effect) but by an increase of perilymphatic oxygenation. Therefore carbogen inhalation was used for the treatment of sudden deafness. In a prospective randomized study, carbogen inhalation yielded significantly better results than the intravenous infusion of papaverine and low-molecular dextran. Carbogen inhalation is recommended for the effective, noninvasive treatment of sudden deafness.