Interferon-alpha-2b/ribavirin-induced vestibulocochlear toxicity with dysautonomia in a chronic hepatitis C patient

Cochlear Changes Caused by Peginterferon α-2b

To evaluate the effect of peginterferon α-2b on guinea pigs' hearing and its cochlea, and to determine whether these effects are permanent or reversible. This study is an experimental animal study done on the organs of Corti of 30 guinea pigs after a peginterferon α-2b injection course. The cochleae of guinea pigs were extracted and examined by scanning electron microscopy for the right side and immunohistochemistry for the left side. All guinea pigs were subjected to pinna reflex, otological examination, and distortion product otoacoustic emission (DPOAE) both before and after the receiving of interferon (IFN). Electron microscopic scanning and immunohistochemistry of the cochleae revealed that peginterferon α-2b has a harmful effect on guinea pigs' cochleae, in the form of structural changes in the hair cells and supporting cells with apoptotic changes in the organ of Corti and the stria vascularis. These changes were reversible. DPOAE showed a significant reduction in distortion product mean amplitude and signal-to-noise ratio in all frequencies after 3 days from the last dose of IFN injection except at 1,006 Hz. After 14 days, there was a significant improvement in most of the frequencies, but are still below the normal values.

Bilateral sudden sensorineural hearing loss: review

Introduction:

Unilateral and bilateral sudden sensorineural hearing loss represent different disease entities. The unilateral condition is more common and predominantly idiopathic, and up to 65 per cent of patients spontaneously recover hearing. Conversely, the bilateral condition is rare, mostly associated with serious systemic conditions, and has a higher prevalence of morbidity and mortality.

Methods:

A literature search using the PubMed database was conducted using the MeSH terms ‘sudden’, ‘bilateral’ and ‘sensorineural hearing loss’.

Results:

One hundred and three reported cases of bilateral sudden sensorineural hearing loss were identified. The condition is most often associated with toxic, autoimmune, neoplastic and vascular conditions. A younger age of onset, with a bimodal age distribution, was seen for bilateral sudden sensorineural hearing loss, compared with the unilateral condition. Patients with the bilateral condition had more profound hearing loss, with poorer recovery and a 35 per cent mortality rate. Vestibular symptoms were also less common than in the unilateral condition.

Conclusion:

The presentation of bilateral sudden onset sensorineural hearing loss is a medical emergency requiring thorough and urgent investigation to exclude life-threatening and reversible conditions.

Distortion-product otoacoustic emissions: a useful test for monitoring ototoxicity induced by pegylated interferon and ribavirin treatment in patients with chronic hepatitis C

Pegylated-interferon (peg-IFN) and ribavirin combination therapy for the treatment of hepatitis C virus (HCV) infection is well known to be associated with significant adverse effects. Several studies have investigated a possible auditory pathway involvement during IFN therapy, but a method to monitor the potential auditory involvement during treatment has not yet been described. The aim of this study is to evaluate possible modifications of the outer hair cell (OHC) function in HCV patients receiving peg-IFN and ribavirin combination therapy. Thirteen adult HCV patients (8 F/5 M, mean age 52∓12 years) treated with peg-IFN and ribavirin combination therapy underwent Pure Tone Audiogram and Distortion Product Otoacoustic Emission (DPOAE) tests. We compared mean auditory thresholds (PTA) and mean DPOAE amplitude before, at month 3 during, and at the end of treatment (T0, T3, and Tend, respectively), and 3 months after treatment discontinuation (Tfu). No significant differences were found in hearing levels at the different time points analyzed. During treatment, three patients developed tinnitus, which in 2 cases resolved spontaneously after the end of therapy. Compared to T0 (19.5±0.83), a statistically significant DPOAE increase at T3 (30±1,26) and Tend (28.6±2.16) was found (p<0.05 at both time points), while DPOAEs returned to pre-treatment levels at Tfu (19.3±1.3). In our group, none of the patients reported a permanent auditory impairment, excluding one patient with persistent tinnitus. Peg-IFN could produce an increase of motility of the OHCs by means of intracellular pathways. DPOAE test could be considered a new method for monitoring ototoxicity induced by IFN. On the basis of recent literature and our audiological results, physicians should be aware of the possible ototoxic effects of peg-IFN, requiring appropriate surveillance, and the patient should be informed of the potential side effects of IFN therapy on the auditory pathway.

The effects of pegylated interferon/lamivudine therapy on auditory functions in patients with chronic hepatitis B

OBJECTIVES

The aim of this study was to assess the effects of pegylated interferon monotherapy and pegylated interferon+lamivudine combination therapy on auditory functions in patients with chronic hepatitis B (CHB) infection.

METHODS

A total of 54 patients with a diagnosis of CHB were grouped into four treatment groups: patients in Group 1 received pegylated interferon-alpha 2a; patients in Group 2 received pegylated interferon-alpha 2a+lamivudine; patients in Group 3 received pegylated interferon-alpha 2b, and patients in Group 4 received pegylated interferon-alpha 2b+lamivudine treatment. The auditory system (using standard and high frequency audiometry) and the vestibulocochlear adverse effects including otalgia, tinnitus, vertigo and imbalance were assessed immediately before the onset of the study, and at the 12th, 24th, and 48th weeks of the study.

RESULTS

A mean elevation of auditory threshold of 1-10dB was found in all treatment groups when the thresholds at the onset of the study and the thresholds at the 12th, 24th, and 48th weeks were compared. However, the elevations were not significant. The elevations were mostly at high frequencies (10,000, 12,000 and 16,000Hz). The most common vestibulocochlear adverse effects related to treatment were tinnitus, vertigo, imbalance, and otalgia, respectively. Tinnitus was the most common adverse effect in Group 2, vertigo was the most common in Group 3, imbalance was at equal frequency in Group 2 and 3, and otalgia was the most common adverse effect in Group 2 (p>0.05).

CONCLUSION

There were no significant auditory adverse effects in the treatment groups. We think that it may be beneficial to monitor the auditory functions in patients receiving PEG-IFN treatment because of the mild elevation in the auditory thresholds (although not significant).