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Three firms in the USA make cochlear implants and nearly 10 000 American children have such a device. In June 2002 one of the manufacturers notified the US Food and Drug Administration of 15 reports of cochlear implant-associated bacterial meningitis. This firm’s implants included a positioner, a small Silastic wedge intended to keep the electrode pressed against the medial wall of the cochlea, and it was suspected that the positioner might be implicated in the meningitis cases. These implants were recalled in July 2002 but cases of meningitis were also reported in children who had had implants made by the other two firms that did not have a positioner. Data have now been reported (
, see also perspective article, ibid: 421–3) about all 4264 children under 6 years of age who had a cochlear implant in the USA between 1 January 1997 and 6 August 2002.
Twenty-three children each had one episode of bacterial meningitis and three had two each. The causative organisms were Streptococcuspneumoniae (15 episodes), nontypeable Haemophilus influenzae (3), H influenzae type b (2), Acinetobacter baumanii (2), Escherichia coli (1), enterococcus (1), and unknown (5). The meningitis occurred within 30 days of implantation in nine children but the longest time from implantation to meningitis was 3 years. Eight children had otitis media at the time of presentation with meningitis. One child died. Three had the implant removed.
The incidence of pneumococcal meningitis (138 cases per 100 000 child-years at risk) was more than 30 times higher than in children of the same age in the US population. Use of a positioner was associated with 4.5-fold increase in meningitis compared with implants without a positioner. Children who had both a CSF leak during surgery and radiological evidence of a middle ear malformation had a ninefold increase in risk compared with other children with an implant.
The authors of this paper emphasise the importance of immunisation against pneumococcus and Hib and of prompt response to symptoms suggestive of meningitis and early treatment of otitis media in all children with a cochlear implant.