Two cases of acute vestibular dysfunction associated with interferon-α therapy

Abstract

Interferon-α (IFNα) has been recognized to be effective for the treatment of chronic hepatitis B or C. At the same time, it has been reported that IFNα can cause various side effects such as hearing loss, sensory neuropathy, retinopathy, behavioral changes, and so on. Acute vestibular dysfunction without cochlear symptoms has rarely been reported. We encountered two patients who had acute vestibular dysfunction without cochlear symptoms associated with IFNα therapy for chronic hepatitis. A 53-year-old woman was treated daily with 6 million U of IFNα for hepatitis C. On the second day of IFNα treatment she experienced dizziness. She did not have any cochlear symptoms or other neurological symptoms. On examination, she showed bilateral decreased caloric responses. A 32-year-old man was treated daily with 6 milion U of IFNα for hepatitis B. In the third week of IFNα treatment, he experienced spontaneous vertigo without cochlear or any other neurological symptoms. On examination he showed right-beating spontaneous nystagmus and decreased caloric responses on left ear stimulation. After discontinuation of IFNα therapy, caloric responses were recovered in both patients. Although the mechanism of acute vestibular dysfunction associated with IFNα therapy is still unclear, IFNα associated acute vestibular dysfunction might be caused by microvascular problems. We need to be mindful of IFNα associated acute vestibular dysfunction without cochlear symptoms.