Case Presentation: A 58 year old female with history of sensorineural hearing loss at 25 years of age due to meningitis presented with severe right ear pain. She underwent a right cochlear ear implant three years ago with uncomplicated postoperative course. The patient also endorsed subjective fever, chills, nausea and dizziness. Laboratory results were notable for leukocytosis 13.9, CRP 105 and ESR 43. Physical exam revealed edema, erythema, warmth and exquisite tenderness at the right implant site. Left cochlear site was without concern. CT head did not show soft tissue infection. The patient was initiated on antibiotics with little improvement and therefore reevaluated by otorhinolaryngology (ENT). It was interesting to note that she had a de-novo cochlear implant in the contralateral ear (left ear) a month prior to current presentation. There was a concern for foreign body antigenic response given her recent surgery more than infection of a chronically placed right cochlear implant. She received high dose steroids with significant improvement in symptoms. The patient was discharged on a steroid taper and ultimately underwent explantation of the right cochlear implant. Microbiological cultures sent during explantation were without bacterial or fungal growth; pathology revealed multinucleated giant cells, confirming non-allergic foreign body reaction.

Discussion: Cochlear implant is a safe procedure for sensorineural hearing loss with low complication rate. When reported, complications include misplaced electrode, intractable vertigo, skin flap necrosis or wound infection. Only a few case reports cite cochlear implant removal due to foreign body reaction. Suspicion should arise with infection-like presentation but no improvement following antibiotics. Diagnosis is with histology and the presence of multinucleated giant cells as foreign-body reaction represents the end-stage response of inflammatory and wound healing following implantation of a medical device. Interestingly, foreign body reaction can occur immediately or years following implantation. Treatment is with steroids and device removal. Foreign body reaction should be considered in patients with cochlear implants to ensure timely and appropriate therapy in this inflammatory condition often mistaken for infection.

Conclusions: Often mimicking infection, foreign body reaction following cochlear implantation is an extremely rare cause of inflammation, with only a few cases cited in the literature. We present the case of an even more peculiar occurrence, when cochlear implant induced inflammation of the contralateral ear.