Susceptibility genes for gentamicin-induced vestibular dysfunction

Spontaneous spondylodiscitis and epidural abscess due to Listeria monocytogenes in a middle-aged patient with gentamicin related side effects: A case report and a review of literature

Introduction

Primary spondylodiscitis due to Listeria monocytogenes (LM) is a rare condition.

Research question

We present a case of spontaneous LM spondylodiscitis with an epidural abscess in a middle-aged man, who reported no gastrointestinal infection.

Material and methods

We identified 5 spinal infection cases due to LM in the literature, with 3 diagnosed as primary spondylodiscitis.

Results

The patient was treated with surgical decompression, debridement, and antibiotic therapy. Blood cultures remained negative throughout the case and microbiological cultures were obtained during surgery. The patient developed side-effects of prolonged gentamicin therapy but made a recovery from his spinal complaints at 6-months follow-up. Listeriosis is a relatively rare food-borne disease with a wide spectrum of presentation. Surgeons should consider more aggressive therapy for spinal infections and recognize the uncommon manifestations. We identified 3 primary and 2 secondary LM spondylodiscitis cases in the literature. Antibacterial treatment of LM spondylodiscitis varied in agents and duration, but no side-effects were previously reported. Gentamicin treatment requires care and attention to complications.

Discussion and conclusion

Listeria monocytogenes is a rare cause of primary spondylodiscitis. Further studies are needed to establish a safe treatment protocol for treatment with gentamicin and LM spondylodiscitis.

Gentamicin vestibulotoxicity with modern systemic dosing regimens: a prospective study using video-oculography

Objectives: To determine the incidence of gentamicin vestibulotoxicity with current dosing regimens, and to evaluate the feasibility of routine video-oculography on all patients given gentamicin. Materials and methods: In this prospective incidence study serial horizontal vestibulo-ocular reflex (HVOR) gain measurements were recorded using video-oculography on adult inpatients receiving intravenous gentamicin. The primary outcome was the proportion of patients developing impairment of their HVOR gain. Results: After exclusions, 42 patients were included in the analysis. Three patients (7.1%) developed asymptomatic vestibulotoxicity, exact 95% confidence interval 1.5-19.5%. In two of these patients the deficit resolved within several hours. No patients developed symptomatic vestibulotoxicity. There was no evidence for a generalised reduction in group HVOR gain with time. HVOR gain was not associated with total gentamicin dose, dynamic visual acuity or subjective imbalance. Conclusions and significance: Gentamicin may cause reversible, asymptomatic vestibulotoxicity. Video-oculography may be useful to monitor for vestibulotoxicity in patients treated with gentamcin; however, testing all patients routinely may be challenging.

Delayed endolymphatic hydrops. Special emphasis on nystagmus associated with episodes and contribution of chemical labyrinthectomy

OBJECTIVES

The main objective was to describe spontaneous nystagmus characteristics during an episode of delayed endolymphatic hydrops (DEH), including an initial vertical upbeating nystagmus in one patient. The secondary objective was to highlight the contribution of chemical labyrinthectomy.

METHODS

Episodic vertigo after a prolonged period of time of sensorineural hearing loss (profound or total) in one ear characterized ipsilateral DEH and was associated with the development of hearing loss in the opposite ear in contralateral DEH.

RESULTS

Ten patients met the criteria for DEH: 7 ipsilateral and 3 contralateral. Three (all ipsilateral DEH) were examined during a vertigo episode. Two patients had a typical horizontal-torsional nystagmus beating contralaterally to the hearing loss. One patient showed atypic initial vertical upbeating nystagmus with a slight torsional component, which secondarily became horizontal-torsional beating contralaterally to the hearing loss. Four patients had disabling vertigo with unilateral total deafness (ipsilateral DEH), successfully treated by 1-3 transtympanic gentamycin (Gentalline^®) injections.

CONCLUSION

Nystagmus direction during vertigo episodes varies, and may initially present as vertical upbeating nystagmus, which, to our knowledge, has not been previously reported in DEH or Menière's disease. This nystagmus might reflect an inhibition of the superior semicircular canal (on the hearing-impaired side), suggesting incipient hydrops in this canal. Chemical labyrinthectomy is a simple and effective procedure in unilateral DEH, especially as the patient often suffers from total deafness.

Bilateral Vestibular Weakness

Bilateral vestibular weakness (BVW) is a rare cause of imbalance. Patients with BVW complain of oscillopsia. In approximately half of the patients with BVW, the cause remains undetermined; in the remainder, the most common etiology by far is gentamicin ototoxicity, followed by much rarer entities such as autoimmune inner ear disease, meningitis, bilateral Ménière’s disease, bilateral vestibular neuritis, and bilateral vestibular schwannomas. While a number of bedside tests may raise the suspicion of BVW, the diagnosis should be confirmed by rotatory chair testing. Treatment of BVW is largely supportive. Medications with the unintended effect of vestibular suppression should be avoided.

[Current aspects of ototoxicity. Ototoxic substances and their effects]

Ototoxicity describes reversible or irreversible disorders of inner ear functions due to the influence of chemical, biological, or physical substances. Ototoxicity should be kept in mind during differential diagnosis of hearing loss, tinnitus, dizziness, and vertigo. In clinical practice, drug-induced ototoxic effects play a major role. The otorhinolaryngologist should also be involved in interdisciplinary cooperation, e.g., during treatment with antineoplastic chemotherapeutic agents with potential ototoxic side effects. In clinical practice, multimedication and interactions between different agents can complicate precise correlation in individual cases. Recent studies also show that noncellular components, such as otoconia, are extremely sensitive to chemical attacks.

Analysis of polymorphisms and haplotypes in genes associated with vascular tone, hypertension and oxidative stress in Mexican-Mestizo women with severe preeclampsia

OBJECTIVE

Several studies have reported the association of genes related to vascular tone, hypertension, oxidative stress and preeclampsia. We investigated the possible association among three polymorphisms in eNOS (as well their haplotypes): one of MTHFR, one of GSTP1 and one of AGT, with severe preeclampsia in Mexican-Mestizo women.

METHODS

Two hundred thirty women with severe preeclampsia and 350 control subjects were genotyped; for rs2070744 and rs1799983 of eNOS, rs1801133 of MTHFR, rs1695 of GSTP1 and rs699 of AGT we used real-time PCR allelic discrimination and for VNTR of eNOS, PCR. Allele frequency differences were assessed by χ(2). Logistic regression was used to test for associations and for haplotype frequencies using Haploview 4.2.

RESULTS

Genotypic and allelic distribution of the polymorphisms was similar between cases and controls; likewise, haplotype frequencies of the three polymorphisms of eNOS did not differ significantly.

CONCLUSIONS

To our knowledge, this is the first time that these polymorphisms have been analyzed together and exclusively in women with severe preeclampsia. However, we did not find an association between polymorphisms of eNOS, MTHFR, GSTP1 and AGT with severe preeclampsia in our population. Additionally, we observed differences in the distribution of the alleles and genotypes of these polymorphisms in our population in comparison to those described in other ethnic groups.