Sudden Deafness and Viral Infections

Abstract

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.

Sudden Deafness: Is It Viral?

“…Measles and rubella have also been temporally or serologically associated with a few cases of sudden deafness [13,18] . With widespread immunization against mumps, measles and rubella, the incidence of these diseases has fallen drastically, along with the near eradication of these agents as an etiological agent for ISSHL [19] . However, there has not been a concomitant decline in the incidence of ISSHL, further supporting the argument that these particular viruses are not the cause of most cases of ISSHL.…”

“…Other types of viruses such as respiratory viruses, adenovirues and arenaviruses have also been implicated in ISSHL, based on anamnestic or serological data [3,13,19] . On the other hand, some studies have reported lack of increases in antibodies against multiple tested viruses [reviewed by Pitkäranta et al,19 ].…”

“…On the other hand, some studies have reported lack of increases in antibodies against multiple tested viruses [reviewed by Pitkäranta et al,19 ]. In patients with ISSHL, Pitkäranta and Julkunen [24] could not detect production of interferon or interferon-induced gene expression in peripheral blood samples, both of which are useful diagnostic markers for systemic viral infections.…”

Sudden sensorineural hearing loss: Is antiviral treatment really necessary?

“…Many studies, however, reported that mumps virus was only responsible for a very small fraction of ISSHL cases (less than 10%) [7,8], and, measles and rubella virus has been reported as a rare cause of ISSHL serologically in few cases [7,10]. Indeed, these agents, which were considered in the etiology of ISSHL, are almost eradicated thanks to a worldwide vaccination [11].…”

Sudden hearing loss as a first complication of long‐standing Type 1 diabetes mellitus: a case report

“…The cause and pathophysiology of ISSNHL loss remains unclear. The main pathogenic mechanisms are possibly related to vascular disturbances or immunological reactions, perhaps secondary to viral infectons [7–10]. The incidence of ISSNHL is difficult to estimate as spontaneous remission occurs in 70% of the cases [11].…”