Cochlear Implant Recipients may be at Greater Risk for Meningitis - Information Update

Date: 2003-02-17

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The Marketed Health Products Directorate (MHPD), Therapeutic Products Directorate (TPD) and Biologics and Genetic Therapies Directorate (BGTD) post safety alerts, public health advisories, press releases and other notices from industry as a service to health professionals, consumers, and other interested parties. Although MHPD, TPD and BGTD approve therapeutic products, MHPD, TPD and BGTD do not endorse either the product or the company. Any questions regarding product information should be discussed with your health professional.

From the Marketed Health Products Directorate, Therapeutic Products Directorate, and the Health Products and Food Branch Inspectorate

February 17, 2003

To: Hospital Chief of Medical Staff

Please forward to the relevant Departments of Surgery; Otolaryngology; Pediatrics; Geriatrics; Internal Medicine; Intensive Care Units; Infection Control; Family Medicine; Emergency and involved professional staff and post this NOTICE in your institution.

Cochlear Implant Recipients may be at Greater Risk for Meningitis - Information Update

On July 29, 2002, Health Canada issued a notice to hospitals entitled Cochlear Implant Recipients May be at Greater Risk for Meningitis. This notice provides an update on this issue, including updated information about the reported cases of bacterial meningitis and the cochlear implants themselves, factors that predispose cochlear implant recipients to bacterial meningitis, and immunization and prevention strategies. The original document may be found at: http://www.hc-sc.gc.ca/dhp-mps/medeff/advisories-avis/prof/_2002/implant_cochle_nth-ah-eng.php

Health Canada has become aware of new information about the possible increase of bacterial meningitis in cochlear implant recipients. In Canada, five cases of bacterial meningitis have been reported in patients with cochlear implants; three cases were in children and two in adults. One paediatric case was fatal. The time interval from implant to onset of meningitis ranged from 4.5 months to 4.25 years. Causative organisms identified include Streptococcus pneumoniae (3 cases), Haemophilus influenzae type f (1 case) and haemolytic streptococcus group B (1 case).

The theoretical risk of developing bacterial meningitis in cochlear implant recipients has been known for some time but current epidemiologic studies may provide an assessment of the magnitude of this risk. To date, more than 90 cases have been reported worldwide in a population base of approximately 60,000 implantations. The US Food and Drug Administration advisory on this subject may be found at:  http://www.fda.gov/cdrh/safety/cochlear.html

In Canada, about 2000 people have received implants from two manufacturers: Cochlear Corporation (since 1987) and Advanced Bionics Corporation (since 1994). A third manufacturer, Med-EL has recently received a device licence for the Combi-40+ device.

What are Cochlear Implants?

Cochlear implants are medical devices that contain an electrode which is positioned in the cochlea (inner ear) to activate auditory nerve fibres allowing for transmission of sound signals to the brain.

What is bacterial meningitis?

Bacterial meningitis is an infection of the lining of the surface of the brain which is caused by certain bacteria. The yearly incidence of bacterial meningitis is approximately 3 to 5 cases per 100,000 population. (ref. Harrison's Principles of Internal Medicine, 14th Edition, 1998, p. 2419)

Early symptoms of meningitis include fever, irritability, lethargy and loss of appetite in infants and young children. Older children and adults may suffer from headache, stiff neck, photophobia, nausea and vomiting, and confusion or alteration in consciousness. Physicians should consider a diagnosis of meningitis in any patient, but especially in cochlear implant patients, when such symptoms exist. Children under 2 years of age have the highest risk of developing meningitis. The same bacteria cause meningitis in cochlear implant recipients as in other patients.

Predisposing Factors

The mechanism of infection for bacterial meningitis in cochlear implant recipients has not been established. The electrode of the cochlear implant is positioned in the inner ear, which is in close proximity to the brain. Some deaf people may have congenital abnormalities of the cochlea which predispose them to meningitis even prior to implantation. Individuals who became deaf as a result of meningitis may be at increased risk of subsequent episodes of meningitis. Surgical implantation of the device in a patient who has a middle ear infection may increase the risk of a post-operative infection of the inner ear, and subsequent meningitis. The cochlear implant, because it is a foreign body, may act as a source for infection when patients have bacterial illnesses. This minimal increase in risk is seen with all medical device implants.

One hypothesis for the increased risk of meningitis is that the design of the electrode with a positioner, as found in the ClarionTM HiFocus I and Hi Focus II may be a predisposing factor. Advanced Bionics Corporation now markets the ClarionTM HiFocus electrode without the positioner.

Prophylaxis:

Surgeons are encouraged to consider prophylactic antibiotic treatment prior to implantation, as appropriate, and physicians should diagnose and treat otitis media promptly in patients with cochlear implants.

Vaccination

Cochlear implant candidates, as well as those individuals who have already received the implant, may benefit from immunizations against organisms that are known to cause bacterial meningitis. All persons with implants and candidates for cochlear implants should be up-to-date with their immunizations. The National Advisory Committee on Immunization has made specific immunization recommendations for recipients of cochlear implants. These recommendations are available at:  http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/03vol29/acs-dcc-2-3/acs-2.html

What is Health Canada doing to address this situation?

1. Health Canada is conducting investigations into the potential association between having a cochlear implant and the risk of developing bacterial meningitis. Since July 2002, Health Canada has been conducting enhanced surveillance of bacterial meningitis, and this is ongoing. As well, the Department is conducting a survey of all cochlear implant recipients in Canada who have received implants since 1995. The objectives of the survey are to determine the rates of bacterial meningitis among the cochlear implant population and to determine if the risk of bacterial meningitis among cochlear implant recipients is related to the type of implant and/or the manufacturer of the device. The results of this investigation should be available early in 2003.
   
   
2. Health Canada is working with the US Food and Drug Administration, the Centers for Disease Control and Prevention, European health agencies and Canadian health care professionals to obtain additional information relevant to this issue.
   
   
3. Health Canada is working with the manufacturers of cochlear implants. A new device licence has been issued to Advanced Bionics for a modified electrode design for the Clarion^TM device. A review of the Labelling of the Cochlear Corporation Nucleus^TM 24 cochlear implants has been conducted, and revised labelling has been implemented for the most recently licensed cochlear implant, the MED-EL Combi 40+^TM. Health Canada is working with manufacturers on risk management and communication activities, including distribution of information letters providing updated information to health care professionals and implant recipients.
   
   
4. At the request of Health Canada, the National Advisory Committee on Immunization has made immunization recommendations for cochlear implant recipients. These recommendations will be published in the February 15, 2003 supplement to Canadian Communicable Disease Report and are posted at the following address:  http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/03vol29/acs-dcc-2-3/acs-2.html

Reporting Cases of Meningitis in Cochlear Implant Recipients

Health care professionals are reminded that most cases of bacterial meningitis are notifiable and should be promptly reported to your local Medical Officer of Health. Also, please report cases of meningitis in cochlear implant patients directly to the device manufacturer and to the Health Products and Food Branch Inspectorate of Health Canada at: 1-800-267-9675.

For additional information about the Health Products and Food Branch Inspectorate, please consult our website: Inspectorate website: www.hc-sc.gc.ca/dhp-mps/compli-conform/index-eng.php