الفهرس 
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Abstract
Sudden sensorineural hearing loss is a sensorineural hearing impairment that develops over a period of a few hours to a few days.
Several theories have been proposed regarding the development of SSNHL. There is considerable evidence suggesting that hearing can be influenced by immunity in the inner ear.
It is extremely important to recognize immune disorders of inner ear because they are among the few forms of hearing loss that are currently amenable to medical treatment.
The pathogenesis of autoimmune hearing loss includes vasculitis of inner ear vessels, cross-reacting antibodies, or autoantibodies directed against inner ear antigenic epitopes.
The hypothesis that vascular damage might have a pathogenetic role in immune-mediated SSNHL is supported by labyrinthine fibrosis and cochlear ossification found in patients affected by autoimmune disorders and SSNHL.
This work aimed to detect to what extent the vascular damage could have a role in the pathogenesis of SSNHL and to evaluate the role of AECA as a serological marker of vasculitis in patients with SSNHL.
The material of this study entailed fifty patients with ISSNHL. Thirty healthy subjects, with matching age and sex, were included in the study as a control group.
Some quantitative immunological parameters, AECA, ESR and CRP, were estimated in patients’ and controls’ sera. Qualitative parameters, namely ANA and ANCA, were estimated as well.
ESR, CRP and AECA levels showed highly significant elevations in patients group as compared to controls. Thus these parameters could be of value in suspecting immune-mediated vasculitis in hearing loss.
As regards ANA and ANCA, no positive cases were noticed among controls. In the patients group, 6.0% (3/50) of the patients were positive for ANA and a total of 27/50 patients (54%) were ANCA-positive and thus differed significantly from normal controls.
So, the majority of patients in the current study could be considered as ANCA-associated vasculitis as a cause of their HL while only 3 patients out of 50 (6.0%) were positive for ANA and this notion could be explained as the patients with systemic autoimmune disorders were excluded from this study, as all cases were ISSNHL.
On comparing AECA levels in patients with moderate, severe and profound HL, its levels showed a highly significant difference which means that AECA levels are correlated to disease activity.
A comparison between ANCA-positive patients versus ANCA-negative patients as regards AECA levels showed that its levels were significantly elevated in ANCA-positive patients.
Correlation studies revealed a highly significant positive correlation between AECA levels and both of ESR and CRP, which indicates that the cause of rising of all these parameters is almost the same.
Finally, the results obtained by the ROC curve indicate that AECA may provide a valuable tool for detecting inner ear vasculitis as a cause of SSNHL.
from the above mentioned results, it could be concluded that vasculitis of the inner ear may play a role in the pathogenesis of some cases of ISSNHL. It may occur with any age, sex and with any degree of HL.
ESR and CRP should be taken in consideration as a routine screening test for such cases. More specific laboratory investigations are warranted when ESR and/or CRP are elevated
AECA may represent a serological marker of immune-mediated vascular damage in SSNHL. Being inexpensive and feasible test, it could be used early in the disease for proper early diagnosis and to identify a subset of patients that can potentially benefit from immunosuppressive therapy for stabilization of and possibly improvement in hearing.