sudden sensorineural hearing loss ( ssnhl ) is defined as a hearing loss of greater than 30 db hl consecutively over three pure tone frequencies occurring within 72 hours . ssnhl occurs frequently but it is difficult to identify its etiology with certainty in most cases . about 85% of cases diagnosed as ssnhl are catagorized as idiopathic and managed with empirical treatment . possible causes of ssnhl include infectious , vascular , immune - mediated disorder , other neurological diseases , neoplasms , or ototoxicity . the risk of intralabyrinthine hemorrhage ( ilh ) has been reported to be high in the patients having hematological disease , under anti - coagulation therapy . since the signal intensity in the normal labyrinth on t1-weighted magnetic resonace image ( mri ) is usually isotense compared to the cerebrospinal fluid ( csf ) , ilh is strongly suspected when a high signal intensity is noted on pre - contrast t1-weighted mri image . here we report a case of ssnhl that deteriorated rapidly to deaf , and its possible cause as ilh . a 59-year - old female presented with sudden onset of hearing loss and tinnitus in the right ear , followed by vertigo after two days . thirteen years ago , she has experienced sudden hearing loss in the right ear . the hearing threshold of the right ear was 80 db hl , and speech discrimination score was 40% . after oral prednisolone medication , low tone hearing impairment was improved up to 40 db hl ( fig . follow up , there was no episode of hearing fluctuation or dizziness , she only complained of intermittent tinnitus . at present , but after three days , the spontaneous nystagmus disappeared and there was no vestibular weakness on caloric test ( fig . mri scans were performed to rule out a retrocochlear lesion , and showed strong signal intensity in the right vestibule , especially on the pre - contrast t1-weighted image ( fig . the signal intensity was equally high in both labyrinth and vestibule on the enhanced t2-weighted image ( fig . 2c ) . this signal change was confined to the right vestibule and semicircular canals and right cochlea appeared normal . these radiologic findings supported the diagnosis of ilh and the patient was prescribed to stop aspirin in order to reduce the risk of ongoing hemorrhagic condition in the labyrinth . also , high dose prednisolone ( 60 mg / day ) was added . the hearing threshold was same after 6 months later and the results of coagulation test , antinuclear antibody test and rheumatoid factor test were within normal range . because the follow - up hearing did not show any improvement , a cochlear implantation was performed after 22 months since second onset of sudden hearing loss . the hearing threshold on implanted side was about 25 db hl and she showed a good functional outcome . , hematologic disorders such as leukemia , sickle cell anemia , pernicious anemia and hyperviscosity disorders may increase the risk of ilh . and other studies in animal experiments showed that perilymphatic , endolymphatic hemorrhage by microvessel occlusion caused hearing loss . some cases of sudden hearing impairment have been reported in patients taking anticoagulants such as warfarin or aspirin . moreover , it is known that secondary ilh could be occured by tumors , labyrinthitis and trauma . poh and tan   reported that radiotherapy could cause ilh and defined the etiology as vascular causes , inner ear membrane damage and capillary dilation or proliferation of small sized vessels inside stria vascularis . in our case , although ilh was confined to the vestibule , the deterioration of hearing was severe and there was no improvement . it can be postulated that ischemic damage secondary to vestibular hemorrhage may had serious effect on hearing in weakened cochlea . mri is a distinguishable tool for not only retrocochlear lesion but also any pathologic change in labyrinth . although normal membranous labyrinth shows the similar intensity with csf on enhanced t1 or t2-weighted image , ilh shows high intensity typically on pre - contrasted t1-weighted image due to the methemoglobin increasing during subacute period . generally it is known that lipid , hemostasis , high protein concentration , and hemorrhage show high intensity on t1-weighted image , and it is maintained on post - contrasted t1 image . however , t2 images can be variable in ilh according to the hemorrhage stage . dizziness , accompanied with sudden hearing loss , is one of the main symptoms of ilh , and dizziness due to ilh easily subsides within a few days . spontaneous nystagmus was not checked in some cases of dizziness in ilh . according to jang and kim , caloric test is not distinctive , and the results may be either normal or abnormal . in our case , the dizziness symptom dramatically improved and there was no canal paresis on caloric test ( fig . even though recovery rate of sudden hearing loss is usually known as 47 - 63% including partial recovery , the reported results of sudden hearing loss caused by ilh is relatively poor . hearing loss by labyrinthine hemorrhage was reported to improve after discontinuing anticoagulant in marfan syndrome . in cases of aplastic anemia , leukemia or post - radiation therapy of head and neck lee , et al .   reported partial improvement of hearing by early steroid medication and intratympanic steroid injection even in cochlear hemorrhage . also , it should be noted that the initial level of hearing is associated with the prognosis of ssnhl because it reflects the extent of damage in the cochlea . recurrent ssnhl may be attributed to other underlying diseases such as meniere attack , autoimmune disease , and antiphospholipid syndrome . in our patient , also , the interval between the two episodes of sudden hearing loss was 13 years . such prolonged interval and lack of recurrent dizziness or hearing fluctuation renders the possibility of meniere 's disease unlikely . we postulate that the ssnhl in our case is caused by ischemic injury to the cochlea resulting from hemorrhage in the vestibule as shown in the mri . subsequent mri performed after 22 months showed that the signal change in the vestibule returned to normal . in conclusion ilh may deteriorate hearing suddenly and this condition should be considered as a possible cause of ssnhl , especially in patients with anticoagulation treatment or hematologic disorder . although hearing improvement by ilh is usually not dramatic , early diagnosis and removal of the predisposing cause may be helpful . and mri imaging study is also a valuable tool for the diagnosis of sudden hearing loss .
sudden hearing deterioration may occur in our population , but it is difficult to explain the exact pathophysiology and the cause . 
 magnetic resonance imaging ( mri ) in sudden sensorineural hearing loss ( ssnhl ) is usually useful to evaluate neural lesions such as acoustic schwannoma and hemorrhage in labyrinth . 
 recently some cases of ssnhl caused by intralabyrintine hemorrhage were reported by the advance of mri . in the case of intralabyrintine hemorrhage , 
 mri showed a hyperintense signal in the labyrinth on the pre - contrast and contrast enhanced t1-weighted image and relatively weak intensity on t2-weighted image . 
 the prognosis ssnhl by intralabyrintine hemorrhage is generally known to be poor . 
 we report a case of sudden deafness with intralabyrintine hemorrhage who has a history of anticoagulant administration , with a review of literature .