Morphological Changes in the Cochlear Aqueduct Following Herpes Simplex Virus Inoculation into the Subarachnoid Space

Yanagita, N; Koide, Junichi; Yokoi, Hisashi

doi:10.3109/00016488809125086

Cited by 8 publications

(6 citation statements)

References 6 publications

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“…Upper airway infections (UAI) and intracranial infections may reach the inner ear through the blood (stria vascularis) and through the cochlear aqueduct or internal acoustic meatus IAM 3,32 . Notwithstanding, it is noticed that the few cases of meningoencephalitis have HL associated, because the cochlear aqueduct present defense mechanisms that prevent the spread of the viral agent for the inner ear, reducing the risk of structural lesion and consequent hearing loss 32 .…”

Section: Viral Causesmentioning

confidence: 99%

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Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

Lazarini¹,

Camargo²

2006

Rev. Bras. Otorrinolaringol.

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Several factors have been postulated to elicit the etiology of idiopathic sudden sensorineural hearing loss. Through a bibliographic review, we made a critical analysis of the different etiopathogenic aspects of its clinical manifestation. The most recent studies concerning the possible causes of sudden hearing loss suggest vascular disorders, rupture of the inner ear membrane and autoimmune diseases; however, viral infections have received a great deal of attention in recent years. Little is known about the mechanism of sudden hearing loss. Viruses can cause sudden hearing loss in an acute infection, however the latent form, and its possible reactivation have also been considered as explanations of the cochlear injury mechanism. Even though hearing loss can be explained by a blood viscosity change, experimental and clinical studies do not show any evidence of labyrinthine fibrosis and new bone formation, or labyrinthine membrane breaks. These findings are not in agreement with vascular and rupture membrane factors, respectively. The eventual presence of antibodies against the inner ear suggests that sudden hearing loss pathogenesis may be of autoimmune nature, but the difficulty in establishing the correlation of its morphological and clinical aspects to the hearing loss also do not help to support this statement. Sudden hearing loss is still a controversial and obscure subject in several aspects.

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Section: Viral Causesmentioning

confidence: 99%

“…Notwithstanding, it is noticed that the few cases of meningoencephalitis have HL associated, because the cochlear aqueduct present defense mechanisms that prevent the spread of the viral agent for the inner ear, reducing the risk of structural lesion and consequent hearing loss 32 .…”

Section: Viral Causesmentioning

confidence: 99%

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

Lazarini¹,

Camargo²

2006

Rev. Bras. Otorrinolaringol.

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“…Recent studies ascribe an immunological function to the cochlear aqueduct to protect individuals against bacterial and viral infections [30]. Viral inoculation of the subarachnoid spaces in guinea pigs causes an accumulation of lymphocytes and macrophages, with narrowing of the reticular tissue spaces of the aqueduct [30].…”

Section: Discussionmentioning

confidence: 99%

“…Viral inoculation of the subarachnoid spaces in guinea pigs causes an accumulation of lymphocytes and macrophages, with narrowing of the reticular tissue spaces of the aqueduct [30]. This indicates that the soft tissue can respond defensively to infections [29].…”

Section: Discussionmentioning

confidence: 99%

The cochlear aqueduct in pediatric temporal bones

Bachor¹,

Byahatti

Karmody

1997

Eur Arch Otorhinolaryngol

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The cochlear aqueduct is a bony channel which contains the fibrous periotic duct and connects the perilymphatic space of the basal turn of the cochlea with the subarachnoid space of the posterior cranial cavity. Previous histological studies suggested that patency depended on age, whereas a more recent study showed no statistical correlation between age and patency. To clarify patency in pediatric cochlear aqueducts, we selected 21 temporal bones from 12 infants and children, varying in age from birth to 9 years, in which the cochlear aqueduct was fully visible on one histological section. Photographs were taken for documentation and the length and width of the orifice of the external aperture of the aqueduct at the scala tympani were measured and followed to the internal aperture at the subarachnoid space. The lumen of the duct was examined for mononucleated cells, blood cells and fibrous tissue. Measurements revealed that the mean length of the cochlear aqueduct was 4.6 mm (range, 2.4-10.7 mm), mean width of the external aperture was 484 microm (range, 225-869 microm), and mean width of the internal aperture was 1293 microm (range, 699-2344 microm). The mean diameter of the narrowest part (isthmus) was 151 microm (range, 75-244 microm). In all temporal bones the cochlear aqueduct was patent, with one exception. This latter temporal bone was from a 2-month-old girl with multiple intralabyrinthine anomalies, with the missing cochlear aqueduct believed to be due to an aplasia. Our results support prior measurements of the cochlear aqueduct and demonstrate a short and patent cochlear aqueduct in newborns. With growth, a significant increasing length of the duct was found.

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“…Guinea pig and hamster infection models revealed cochlear inflammatory responses as well as HSV-1 replication in the sensory cells of the labyrinth and in the stria vascularis with the destruction of the organ of Corti and other structures of the cochlea [45,[50][51][52]. Experimental HSV-1 labyrinthitis resembles the histopathology of idiopathic sudden deafness in humans [50,52] and therefore this infection model seems to provide a suitable model system for understanding the pathogenesis of sudden deafness.…”

Section: Experimental Studies In Animalsmentioning

confidence: 99%

Sudden Deafness and Viral Infections

Pitkäranta

Vasama

Julkunen

1999

Otorhinolaryngol Nova

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Sudden deafness is a dramatic and relatively common otological problem. The etiology in most cases remains unresolved although virus involvement has strong support. Sudden deafness has been associated with mumps, rubella, the respiratory and herpes groups of viruses as well as other more rare ones like hantavirus and Lassa virus. Perhaps the bestknown example of virus-induced sudden deafness is acute unilateral hearing loss associated with mumps virus infection. Mumps virus has also been isolated from the inner ear suggesting a direct virus-induced cytolytic mechanism for deafness. Herpesviruses are neurotropic and they have a tendency to become chronic. Therefore they have been strong candidates for viruses being responsible for acute hearing loss. Although serological associations have been found in certain studies, convincing evidence for the involvement of herpes and varicella-zoster viruses as agents causing direct cochlear damage and hearing loss in humans is missing. A number of case reports have associated sudden deafness to rubella, adeno- and hantavirus infections. Multiple studies showing no association of viruses with sudden deafness may reflect seasonal, geographical or epidemiological differences in this disease. This may also bring up the possibility of other etiological factors such as general inflammatory or autoimmune mechanisms for the disease. Histopathological changes in the affected ears are characterized by abnormal cellular architecture in the inner ear with loss of apical and spiral ganglion cells and destruction of the organ of Corti. Similar histopathological changes have been found in experimental animal models infected with mumps, rubella or herpesviruses. Histopathological observations could favor the theory of viral etiology in idiopathic sudden deafness but do not rule out the possibility of immunological disturbances, which would lead to similar histopathological changes.

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Morphological Changes in the Cochlear Aqueduct Following Herpes Simplex Virus Inoculation into the Subarachnoid Space

Cited by 8 publications

References 6 publications

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

The cochlear aqueduct in pediatric temporal bones

Sudden Deafness and Viral Infections

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