Cochlear Implants and Bacterial Meningitis

by Food and Drug Administration (FDA)

Children with a cochlear implant to treat hearing loss have a greater risk of developing bacterial meningitis compared to children in the general population, according to a study conducted by the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration, and state and local health departments.

The study, published in the July 31, 2003, issue of The New England Journal of Medicine, also found that children with a specific type of cochlear implant that had an extra piece called a "positioner" had 4.5 times the risk of developing meningitis compared to those who had other cochlear implant types. However, the study authors note that individuals who are candidates for cochlear implants may have factors that increase their risk of meningitis compared to the general population even prior to being implanted with the device. The study was not able to determine whether the implant, the pre-existing risk factors, or perhaps a combination of both caused the increased occurrence of meningitis in the cochlear implant population studied.

Meningitis is an infection in the fluid that surrounds the brain and spinal cord. Of the two types of meningitis--viral and bacterial--bacterial is the more serious of the two and is the type that has been reported in people with cochlear implants.

The FDA and the CDC began investigating this possible link between cochlear implants and meningitis in July 2002 after receiving reports of bacterial meningitis among children who had received the implants. As soon as the FDA became aware of a possible association between the implants and bacterial meningitis, the agency issued a public health Web notice and began working with manufacturers of cochlear implants to determine the nature and extent of the problem. Because early available information suggested that more cases of meningitis occurred in children with the implant that had the positioner than with other devices, the manufacturer of this implant voluntarily withdrew it from the market in July 2002.

"Working closely with CDC's network for monitoring infection outbreaks is an important part of how we monitor the safety of medical products in use in the population," says FDA Commissioner Mark B. McClellan, M.D., Ph.D. "In this case, we identified a heightened risk of meningitis that demanded prompt action, and the FDA was able to take it."

Nearly 10,000 children and 13,000 adults in the United States with severe to profound hearing loss have a cochlear implant. The implant is an electronic device containing electrodes that are surgically inserted into one of the structures of the inner ear, the cochlea, to activate nerve fibers and allow sound signals to be transmitted to the brain. It can help children with hearing loss perceive sounds and learn to speak.

The study group involved 4,264 children who received a cochlear implant in the United States between Jan. 1, 1997, and Aug. 6, 2002, and who were younger than 6 at the time of the implant. Bacterial meningitis was found in 26 children, and 15 of these children had meningitis caused by the bacterium Streptococcus pneumoniae. Less than one case of the disease would be ordinarily seen in a group this size during the same time period, based on the rates in the general population.

The FDA and the CDC continue to track new cases of meningitis in the United States that occur in people who have cochlear implants.

Advice for Parents

Make sure your child is up to date on vaccines at least two weeks before having a cochlear implant. If your child has already received an implant, check with the child's doctor to ensure that all vaccinations are up to date. (Current vaccines protect against the most common strains of bacteria causing meningitis, but they do not protect against all strains.)

Watch for possible signs and symptoms of meningitis: high fever, headache, stiff neck, nausea or vomiting, discomfort looking into bright lights, and sleepiness or confusion. A young child or infant with meningitis might be sleepy, cranky, or eat less. Contact a doctor promptly if your child shows any of these symptoms.

Watch for signs and symptoms of an ear infection, which can include ear pain, fever, and decreased appetite. Seek prompt medical attention for any possible ear infections.

Talk about the risks and benefits of cochlear implants with your child's doctor and discuss whether your child has certain medical conditions that might make him or her more likely to get meningitis.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.