[Audiovestibular manifestations in systemic vasculitis]

Hearing loss in outbred Hartley guinea pigs experimentally infected with Pichinde virus as a surrogate model of human mammarenaviral hemorrhagic fevers

Lassa fever (LF) is a neglected tropical disease that is caused by Lassa virus (LASV), a human hemorrhagic fever-causing mammarenavirus. A notable sequela of LF is sensorineural hearing loss (SNHL) that can develop in about 33% of the patients. Animal models of LF-associated SNHL have been limited in size and scope because LASV is a biosafety level 4 (BSL4) pathogen that requires its handling in a high biocontainment laboratory. In this report, we describe the development of an alternative arenavirus hearing loss model by infecting outbred Hartley guinea pigs with a virulent strain (rP18) of the Pichinde virus (PICV), which is a guinea pig-adapted mammarenavirus that has been used as a surrogate model of mammarenaviral hemorrhagic fevers in a conventional (BSL2) laboratory. By measuring auditory brainstem response (ABR) throughout the course of the virulent rP18 PICV infection, we noticed that some of the animals experienced an acute but transient level of hearing loss. Cochleae of hearing-impaired animals, but not of controls, had demonstrable viral RNA by quantitative RT-PCR, indicating the presence of virus in the affected inner ear with no overt histopathological changes. In contrast, neither the outbred Hartley guinea pigs infected with a known avirulent strain (rP2) of PICV nor those that were mock-infected showed any evidence of hearing loss or viral infection of the inner ear. This is the first report of an immunocompetent small animal model of mammarenavirus-induced hearing loss that can be used to evaluate potential therapeutics against virus-induced hearing impairment under a conventional laboratory setting.

Giant Cell Arteritis (GCA): Pathogenesis, Clinical Aspects and Treatment Approaches

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Giant Cell Arteritis (GCA), or Horton’s Arteritis, is a chronic form of vasculitis of the large and medium vessels, especially involving the extracranial branches of the carotid arteries, in particular, the temporal artery, with the involvement of the axillary, femoral and iliac arteries too. Arterial wall inflammation leads to luminal occlusion and tissue ischemia, which is responsible for the clinical manifestations of the disease.

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A substantial number of patients affected by GCA present head and neck symptoms, including ocular, neurological and otorhinolaryngological manifestations.

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The aim of this article is to present pathogenesis, clinical aspects and treatment approaches of GCA manifestations.

[Giant cell arteritis: Ischemic complications]

GCA ischemic complications occur generally in patients with a yet undiagnosed or uncontrolled disease. When disease control is fair, ischemic complications may be due mostly to atheromatosis. Ophtalmic complications are most frequent and are dominated by anterior ischemic optic neuropathy. Vasculitic strokes occur essentially in the vertebrobasilar arterial territory. Overt vasculitic coronary disease is exceptional. The diagnosis of upper and lower limbs ischemic complications benefit from advances in echography (halo sign) and positron emission tomography imaging. Treatment relies on corticosteroids (initially 1mg/kg prednisone or more, preceded by intravenous methylprednisolone gigadoses if necessary), the control of cardiovascular risk factors and antiplatelet drugs; heparin may be indicated for threatening limbs ischemia.

Elevated serum macrophage migration inhibitory factor levels correlate with benign paroxysmal positional vertigo and recurrence events

Objective: We aimed to assess the possible relations between serum levels of macrophage migration inhibitory factor (MIF), a central cytokine of the innate immunity and inflammatory response, and benign paroxysmal positional vertigo (BPPV) risk and BPPV recurrence events.

Methods: In the present study, 154 patients with BPPV, and 100 age-and sex-matched control subjects were enrolled in the study. All the patients and controls underwent a complete audio‐vestibular test battery including the Dix–Hallpike maneuver and supine roll test. In the BPPV group, measurements of MIF levels were repeated 1 month after the vertigo attack. The patients were also divided into the recurrence group and the nonrecurrence group in the 1-year follow-up.

Results: The serum levels of MIF in patients with BPPV were higher than in those controls (13.9[interquartile range {IQR}, 8.9–18.4] ng/ml vs. 9.8[7.8–11.8]; P<0.001). As a continuous variable, MIF was associated with increased risk of BPPV (odds ratio [OR] 1.21, 95% confidence interval [CI]: 1.11–1.39; P=0.004) in multiple regression analyses. Recurrent attacks of BPPV were reported in 35 patients, and those patients had higher levels of MIF than those patients were not recurrence (18.0[IQR, 13.6–22.2] ng/ml vs. 12.6[9.3–16.8] ng/ml). In multivariate models comparing the second (Q2), third (Q3) and fourth(Q4) quartiles against the first (Q1) quartile of MIF, levels of MIF in Q4 were associated with recurrent BPPV, and the odds were increased by approximately 305% (OR = 4.05; 95%CI: 1.65–15.44; P=0.009).

Conclusions: Elevated MIF is positively correlated with BPPV risk and BPPV recurrence events, requiring further efforts to clarify the exact mechanism.

Immune-Mediated Systemic Vasculitis as the Proposed Cause of Sudden-Onset Sensorineural Hearing Loss following Lassa Virus Exposure in Cynomolgus Macaques

Lassa virus (LASV) causes a severe, often fatal hemorrhagic disease in regions in Africa where the disease is endemic, and approximately 30% of patients develop sudden-onset sensorineural hearing loss after recovering from acute disease. The causal mechanism of hearing loss in LASV-infected patients remains elusive. Here, we report findings after closely examining the chronic disease experienced by surviving macaques assigned to LASV exposure control groups in two different studies. All nonhuman primates (NHPs) developed typical signs and symptoms of Lassa fever, and seven succumbed during the acute phase of disease. Three NHPs survived beyond the acute phase and became chronically ill but survived to the study endpoint, 45 days postexposure. All three of these survivors displayed continuous disease symptoms, and apparent hearing loss was observed using daily subjective measurements, including response to auditory stimulation and tuning fork tests. Objective measurements of profound unilateral or bilateral sensorineural hearing loss were confirmed for two of the survivors by brainstem auditory evoked response (BAER) analysis. Histologic examination of inner ear structures and other tissues revealed the presence of severe vascular lesions consistent with systemic vasculitides. These systemic immune-mediated vascular disorders have been associated with sudden hearing loss. Other vascular-specific damage was also observed to be present in many of the sampled tissues, and we were able to identify persistent virus in the perivascular tissues in the brain tissue of survivors. Serological analyses of two of the three survivors revealed the presence of autoimmune disease markers. Our findings point toward an immune-mediated etiology for Lassa fever-associated sudden-onset hearing loss and lay the foundation for developing potential therapies to prevent and/or cure Lassa fever-associated sudden-onset hearing loss.IMPORTANCE Lassa virus is one of the most common causes of viral hemorrhagic fever. A frequent, but as yet unexplained, consequence of infection with Lassa virus is acute, sudden-onset sensorineural hearing loss in one or both ears. Deafness is observed in approximately 30% of surviving Lassa fever patients, an attack rate that is approximately 300% higher than mumps virus infection, which was previously thought to be the most common cause of virus-induced deafness. Here, we provide evidence from Lassa virus-infected cynomolgus macaques implicating an immune-mediated vasculitis syndrome underlying the pathology of Lassa fever-associated deafness. These findings could change the way human Lassa fever patients are medically managed in order to prevent deafness by including diagnostic monitoring of human survivors for onset of vasculitides via available imaging methods and/or other diagnostic markers of immune-mediated vascular disease.

Determination of hearing levels in patients with Familial Mediterranean Fever

OBJECTIVE

Familial Mediterranean Fever is the most common congenital, periodic fever condition that affects over 100,000 people worldwide. In the literature, there is limited number of studies about hearing levels in children with Familial Mediterranean Fever. In the present study, we aimed to investigate hearing levels and cochlear functions by using Distortion product Otoacoustic Emission and High Frequency Audiometry (250-20,000 Hz) in pediatric patients with Familial Mediterranean Fever.

METHODS

The study included 62 children with Familial Mediterranean Fever and 27 healthy children with similar age and gender. After otoscopic examination, both groups underwent audiological evaluation including High Frequency Audiometry (250-20,000 Hz) and Distortion product Otoacoustic Emissions. The results obtained were assessed among groups. In addition, these results were compared regarding colchicine use, age at the onset of disease and duration of the diseases in the Familial Mediterranean Fever group.

RESULTS

Of the Familial Mediterranean Fever patients, 93.5% were on colchicine therapy and mean duration of colchicine use was 19.9 ± 13.9 months. The mean age at diagnosis was 6.57 ± 2.86 years (min-max: 2-14) and mean duration of disease was 23 ± 17 months (min-max: 6-84). Pure tone audiometry values, and hearing levels between 9000 and 20,000 Hz were similar and within normal range in both groups. The Distortion product Otoacoustic Emissions responses at the frequencies of 1020, 2040, 3000, 4080 and 5040 Hz were similar for both groups.

CONCLUSION

To the best of our knowledge, this is the first study evaluating hearing levels at the frequencies of 18k Hz and 20k Hz in children with Familial Mediterranean Fever in the literature. In children with Familial Mediterranean Fever, Pure tone audiometry values, hearing values obtained at all frequencies from 250 to 20,000 Hz, and Distortion product Otoacoustic Emissions levels were within normal range. Furthermore, hearing levels were found to be similar to those in healthy children.

[Otorhinolaryngological manifestations in patients with Behçet disease]

INTRODUCTION AND OBJECTIVES

Behçet disease (BD) is a systemic immune-mediated vasculitis of unknown origin characterised by recurrent orogenital ulceration, ocular inflammation and skin lesions. The aim of our study was to identify ear, nose and throat (ENT) manifestations associated with BD.

PATIENTS AND METHODS

Retrospective review of the medical records of all patients diagnosed with BD who attended a tertiary public hospital in Cantabria (Spain) over a period of 22 years. Clinical manifestations, in particular those concerning ENT, were retrieved from medical records. A medical literature review of ENT manifestations was conducted.

RESULTS

Thirty-three patients (age range: 17-64 years) were included in the study. Most of them presented oral ulcers (97%). Eight patients (24%) presented oropharyngeal ulcers and 5 patients (15%) experienced audiovestibular symptoms (high frequency sensorineural hearing loss, vertigo and bilateral vestibular hypofunction). One patient had symptoms compatible with vestibular neuronitis as the presentation manifestation of Neuro-Behçet. In 4 patients (12%) the presence of odynophagia secondary to the presence of oropharyngeal lesions, initially interpreted as acute or recurrent tonsillitis, was the first manifestation of the disease, alone or associated with cutaneous or ocular lesions.

CONCLUSIONS

In addition to the characteristic oral ulcers present in most patients with BD, ulcers in the oropharynx, occasionally interpreted as acute pharyngitis, are also common in these patients. Audiovestibular manifestations frequently appear during the course of the disease and may be the first symptom of central nervous system involvement.

Corticosteroid therapy for hearing and balance disorders

This review addresses the current status of steroid therapies for hearing and vestibular disorders and how certain misconceptions may be undermining the efficacy in restoring normal ear function, both experimentally and clinically. Specific misconceptions addressed are that steroid therapy is not effective, steroid-responsive hearing loss proves an underlying inflammatory problem in the ear, and steroids only have application to the hearing disorders listed below. Glucocorticoid therapy for hearing and balance disorders has been employed for over 60 years. It is recommended in cases of sudden hearing loss, Meniére's disease, immune-mediated hearing loss, and any vestibular dysfunction suspected of having an inflammatory etiology. The predominant steroids employed today are dexamethasone, prednisone, prednisolone, and methylprednisolone. Despite years of use, little is known of the steroid responsive mechanisms in the ear that are influenced by glucocorticoid therapy. Furthermore, meta-analyses and clinical study reviews occasionally question whether steroids offer any benefit at all. Foremost in the minds of clinicians is the immune suppression and anti-inflammatory functions of steroids because of their efficacy for autoimmune hearing loss. However, glucocorticoids have a strong binding affinity for the mineralocorticoid (aldosterone) and glucocorticoid receptors, both of which are prominent in the ear. Because the auditory and vestibular end organs require tightly regulated endolymph and perilymph fluids, this ion homeostasis role of the mineralocorticoid receptor cannot be overlooked in both normal and pathologic functions of the ear. The function of the glucocorticoid receptor is to provide anti-inflammatory and antiapoptotic signals by mediating survival factors.

Vascular Pathophysiology in Hearing Disorders

The inner ear vasculature is responsible for maintenance of the blood-labyrinth barrier, transport of systemic hormones for ion homeostasis, and supplying nutrients for metabolic functions. Unfortunately, these blood vessels also expose the ear to circulating inflammatory factors resulting from systemic diseases. Thus, while the inner ear blood vessels are critical for normal function, they also are facilitating pathologic mechanisms that result in hearing and vestibular dysfunction. In spite of these numerous critical roles of inner ear vasculature, little is known of its normal homeostatic functions and how these are compromised in disease. The objective of this review is to discuss the current concepts of vascular biology, how blood vessels naturally respond to circulating inflammatory factors, and how such mechanisms of vascular pathophysiology may cause hearing loss.

Otolaryngologic manifestations of systemic vasculitis

Systemic vasculitis is a heterogeneous group of diseases of various aetiologies and manifestations. In general, the clinical results derive from ischemia caused by vascular inflammation, which depends on the organ affected. Such vasculitis cases are classified according to the classification of the Chapel Hill conference. They can present with relative frequency as ENT manifestations in both their debut and throughout their evolution. Consequently, the ENT specialist should include them in the differential diagnosis in patients with ENT manifestations that are difficult to control or of atypical presentation. Our objective was to review the most common ENT clinical signs and symptoms in each of these diseases.