Healthcare Infection Prevention - FDA warns of meningitis after cochlear implants
October 1, 2002 4 minutes read
FDA warns of meningitis after cochlear implants
25 cases, nine deaths reported
The Food and Drug Administrations (FDA) reports that at least 25 cases of meningitis have been diagnosed worldwide in children and adults, from age 21 months to 63 years old, who have undergone cochlear implantation for severe to profound deafness. A total of nine deaths have been reported. However, the number of cases may be underreported. A survey being conducted by two physicians who are working with the FDA has uncovered eight additional cases.
That survey is being conducted by Noel L. Cohen, MD, Mendic Foundation professor and chairman in the Department of Otolaryngology at New York University School of Medicine in New York City, and Thomas J. Balkany, MD, chairman of the Department of Otolaryngology, chief of the Division of Otology, Hotchkiss Professor at University of Miami (FL) School of Medicine.
Two of the three companies that manufacture cochlear implants have reported cases of bacterial meningitis in patients who have implants. Cochlear Americas in Englewood, CO, has reported four cases, none of which occurred in the last two years. Cochlear manufactures the Nucleus 24 Contour, and it previously manufactured the Nucleus 24 and Nucleus 22. The physicians’ survey has found four additional cases involving Cochlear, but none within the last two years, Cohen says.
Anne Cosgriff, MD, medical officer at Cochlear, says, "At this point, we feel pretty confident we’ve scoured all the clinics, and the incidences we’ve calculated to this day of post-op meningitis are no higher than incidences of meningitis in general population with or without cochlear implants."
Advanced Bionics Corp. in Sylmar, CA, reported four cases, all of which occurred in the last two years. Advanced Bionics manufactures Clarion implants. The physicians’ survey has uncovered four additional cases involving Advanced Bionics implants, three of which occurred in the last two years.
While no one is certain why there have been additional cases in the last two years, higher risk groups, such as young children, the elderly, and multiple handicapped, are now being implanted, according to Advanced Bionics. Also, the overall number of implants has increased significantly in the last couple of years, particularly in the at-risk age groups, the company says.
Med-El in Durham, NC, has no reported cases, according to a company spokesperson. Med-El manufactures Combi40+ Implants.
Cases appear to be in unvaccinated
Cerebrospinal fluid culture results, which are available in 11 of the 25 worldwide cases, indicate that seven have grown Pneumococcus and four have grown Diplococci (most likely Pneumococcus), according to the FDA. Of the five cases in which a vaccination history against Pneumococcus was available, none had been vaccinated, the agency reports. One particular concern with meningitis is that the symptoms can appear anytime from fewer than 24 hours after an implant to more than five years later.
"You might not relate the symptoms to the device" because of the amount of time that has passed, says Nancy M. Young, MD, head of the Section of Otology at Children’s Memorial Hospital in Chicago.
Early symptoms of meningitis include fever, irritability, lethargy, and loss of appetite in infants and young children. Older children and adults also may have a headache, stiff neck, nausea and vomiting, and confusion or alteration in consciousness. Patients younger than 2 and the elderly are most vulnerable to meningitis, the FDA reports.
Cohen raises several issues with the notification. "What concerns me about the [notification] is, I don’t know where they got numbers from, but the [notification] is very worrisome, and it’s inaccurate in that it doesn’t at all put things into context," he says. He uses the 25 cases as an example. "I don’t know where they got that from," he says. "They switch back and forth with American data and what they say are worldwide data."
Peg Williams, PhD, executive director of the Cochlear Implant Association in Washington, DC, estimates that worldwide, there have been about 33,000 implants. Also, the notification implies that the problem is industrywide, which Cohen says is "open to question."
Another issue is that of the nine deaths, only two are in the United States, Young points out. Only limited information is available for the European cases, she says. "We don’t know if they really were meningitis or what type of meningitis," Young says. Interestingly, thus far, none of the U.S. cases have been in children who have had the vaccine against pneumococcal meningitis, she adds.
Predisposing factors
According to the FDA, there are predisposing factors for meningitis, which may include congenital abnormalities of the inner ear, otitis media, immunodeficiency status, prior history of meningitis, or surgical technique. While the FDA did not respond to requests for interviews, the reference to "surgical technique" may refer to protecting the inner ear following implant by packing some of the patient’s tissue around the electrode to prevent leaking of the fluid out of the inner ear and introducing infection into the cochlea, Cohen says. Also, some devices can cause trauma to the cochlear if they are completely inserted, he says. These "techniques" could cause recipients to be more prone to meningitis, he says. Improper sterile technique also could be a problem in some cases, Young and Cosgriff state.
The FDA is continuing to investigate this issue and gather new information. The notification (www.fda.gov/cdrh/safety/cochlear.html) will be updated as additional information becomes available. While data are being collected, providers are urged to exercise caution. "We don’t have enough data to say for sure that there’s an increased risk, and to what degree," Young says. "We don’t know if there’s any. But we have to assume there could be a problem, and we have to react for the safety of our patients."
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