Cochlear Implant Recipients Have Increased Risk of Meningitis Children with cochlear implants have a small—but increased—risk of contracting meningitis, according to a study by the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and state health departments that appeared in the July 31 issue of the New England Journal of Medicine (NEJM). Last ... Research in Brief
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Research in Brief  |   September 01, 2003
Cochlear Implant Recipients Have Increased Risk of Meningitis
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Hearing Aids, Cochlear Implants & Assistive Technology / Research in Brief
Research in Brief   |   September 01, 2003
Cochlear Implant Recipients Have Increased Risk of Meningitis
The ASHA Leader, September 2003, Vol. 8, 3-39. doi:10.1044/leader.RIB.08172003.3
The ASHA Leader, September 2003, Vol. 8, 3-39. doi:10.1044/leader.RIB.08172003.3
Children with cochlear implants have a small—but increased—risk of contracting meningitis, according to a study by the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and state health departments that appeared in the July 31 issue of the New England Journal of Medicine (NEJM). Last September, ASHA assisted in the epidemiological effort, communicating with audiologists to identify every case of meningitis that occurred.
An increase in meningitis among cochlear implant recipients was first noticed in June 2002. This prompted an ad hoc meeting of European and American otolaryngologists in Amsterdam to exchange information and make recommendations about patient management. As of May 2003, a total of 118 cochlear implant recipients around the world had developed bacterial meningitis, with 63 cases abroad and 55 cases in the United States, including five deaths. The majority of cases in the United States involved children 5 years of age or younger, many of whom developed meningitis within a year after implantation, often within several weeks of surgery.
Because young children are the largest group that will receive implants in the future—and the age group with the highest number of reported cases—the FDA and CDC study sought to determine the incidence of bacterial meningitis in children after cochlear implantation and to identify risk factors for contracting meningitis. The researchers identified 4,264 children who received cochlear implants between 1997 and 2002 and found that 26 developed bacterial meningitis—30 times the incidence among same-aged children in the general population.
One important risk factor was the use of an electrode design that included a positioner that placed the electrode in close proximity to the auditory nerve. Nearly half of all cases of meningitis were attributable to the use of the positioner, which was voluntarily withdrawn by the manufacturer in July 2002.
But even without cochlear implants, children with hearing loss have a higher incidence of meningitis than the general population. Other research found that 23% of children with implants had meningitis before receiving a cochlear implant, placing them at a higher risk for another episode. Another 11.5% of children with implants had inner-ear malformations that are associated with meningitis, such as common cavities, Mondini malformation, cerebralspinal fluid leak, or enlarged vestibular aqueduct syndrome.
“The NEJM article is the most rigorous study to date on this concern,” said John Niparko, an otolaryngologist and director of the cochlear implant center at Johns Hopkins Hospital. “The report suggests that surgery, devices—especially those that use a positioner—and patient factors could contribute to the risk. However, the laws of small numbers as they affected this study don’t allow for definitive conclusions on which of these factors were most responsible.”
In addition to identifying potential risk factors, Niparko said the report underscores two important safeguards: vaccination and vigilance. “Age-appropriate vaccination is now a clear necessity for children and adults with a cochlear implant,” he said. “To my knowledge, there are only rare cases of meningitis in vaccinated individuals as a consequence of a lack of protection against certain subtypes of the infecting microbe.”
Any suggestion of a flu-like illness with fever in a child or adult with a cochlear implant, with or without otitis media, should be evaluated by a physician, Niparko added. “When identified and treated within 48 hours, the outcome of an episode of meningitis is drastically better than when treatment begins 72 hours after symptoms appear. This suggests that all of us who work with patients with cochlear implants should be mindful of the importance of prompt diagnosis and treatment.”
To decrease the risk of meningitis, the study recommends that clinicians:
  • Review vaccination records of cochlear implant recipients and candidates to ensure that they have received pneumococcal vaccinations recommended for those at higher risk. Candidates should be vaccinated at least two weeks before surgery.

  • Know the symptoms of meningitis and encourage parents to be vigilant for possible signs of meningitis.

  • Treat otitis media promptly. In some cases, cochlear implant recipients had signs of otitis media prior to surgery or before meningitis developed.

Visit the CDC Web site at www.cdc.gov/ncbddd/ehdi/cochlear/ for more information about the study and links to the July 31 NEJM article (www.nejm.org) and vaccination recommendations. Visit the FDA Web site at www.fda.gov/cdrh/safety/cochlear.html for an updated public health notification. For more information on meningitis and cochlear implants, contact Gail Linn through the Action Center at 800-498-2071, ext. 4112.
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September 2003
Volume 8, Issue 17