Sudden hearing loss is a type of hearing loss that occurs in three successive frequencies by more than 30 dB and in less than 72 hours. Every 10 person in 100000 in the world and 25000 people in USA suffer this kind of hearing loss. The average age of the onset is 43 years old.

A 34-year-old female with a history of a sudden mild left-sided hearing loss and high-pitched tinnitus along with fullness in the same ear was referred to the audiology clinic. Hearing fluctuation and variability in other symptoms were also reported. Although no complain of any vertigo or balance disorder was mentioned, light headedness was implied. Differential diagnosis of endolymphatic Fistula and retro cochlear lesion was demanded. Audiologic and radiologic findings of this patient are presented in the article to discuss findings regarding the diagnosis of the suspected disorder.