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LETTERS

Cochlear implants and meningitis: update and recommendations for prevention

Bluestone, Charles D. M.D.

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The Pediatric Infectious Disease Journal: May 2003 - Volume 22 - Issue 5 - p 477-478
doi: 10.1097/01.inf.0000068212.52052.53
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In a recent Newsletter in this Journal, the original Food and Drug Administration’s (FDA) Public Health Web Notification was cited that meningitis had been reported in patients who received cochlear implants. 1 I have recently informed my colleagues in otolaryngology concerning the magnitude, etiology and possible pathogenic mechanisms of this problem, and also I recommended methods to prevent meningitis not only in recipients of cochlear implants but also in other patients who have inner ear malformations and could be at risk of developing this potentially life-threatening complication. 2 However, it is important also to update and more fully inform pediatricians about this important public health problem, because the primary care physician is frequently the first professional to encounter these infants and children.

The original FDA Public Health Web Notification has recently been updated and now states that 91 cases have been reported from around the world of which there were 17 deaths. 3 Of the 52 cases reported from the United States, with ages ranging from 18 months to 84 years, 33 (63%) were <7 years of age. O’Donoghue et al. 4 recently estimated that of the 5000 US children <5 years of age who have been implanted, 17 developed meningitis after their implantation, i.e. incidence of >3 per 1000.

The FDA reported that the most common organisms isolated from the cerebrospinal fluid from 23 US patients were Streptococcus pneumoniae (16 cases) and Haemophilus influenzae (4 cases), but 2 patients had Streptococcus viridans and 1 patient had Escherichia coli isolated.

The cause of these attacks of meningitis remains uncertain, but the FDA cites that the design of the implant and the surgical technique to implant them may be factors. After investigating this possibility, one implant (CLARION; Advanced Bionics) has been identified as a possible source of this complication and has recently been removed from the market, but the manufacturers of the implants and implant surgeons are continuing to evaluate other devices and surgical techniques. 3, 4 The FDA also suggested other possible predisposing factors, such as a congenital malformation of the inner ear, otitis media and immunodeficiency. They note that patients with inner ear malformations are predisposed to meningitis even in the absence of a cochlear implant. There have been many case reports published in the past that described children who developed recurrent meningitis, during episodes of otitis media, caused by a congenital defect between the middle and inner ears. Diagnosis of these inner ear malformations in many of these patients, before development of meningitis, can be made by pediatricians and preventive measures instituted.

My recommendations to the primary care physician for infants and children who are cochlear implant recipients, candidates for implantation or others in whom an inner ear malformation may predispose to meningitis are:

  1. Any child who develops sensorineural hearing loss of any degree or has moderate-to- severe vertigo, or both, associated with an episode of otitis media has labyrinthitis and deserves a work-up, which includes complete assessments of hearing and labyrinthine function, tympanocentesis and computed tomography/magnetic resonance imaging of the temporal bones to determine whether there is a defect between the middle and inner ears. Consultation with an otolaryngologist is indicated.
  2. Patients who have had meningitis in association with an episode of otitis media are also candidates for a work-up, which includes tympanocentesis in addition to the spinal tap, and imaging of the temporal bones and brain, to determine whether the meningitis originated in the middle ear or mastoid. If the patient has had recurrent attacks of meningitis during episodes of otitis media, an otogenic origin should still be suspected even in the absence of evidence from temporal bone imaging of a malformation. Again an otolaryngologist should be consulted.
  3. Suppurative complications of otitis media in children who have cochlear implants or who are candidates, as well as other patients who have a documented or suspected defect between the middle and inner ears, should be prevented by prompt and effective treatment of each episode of otitis media; also tympanostomy tube placement, antimicrobial prophylaxis or both are advised for infants and young children who are otitis-prone.
  4. Vaccines against the bacterial pathogens causing meningitis, S. pneumoniae, H. influenzae and Neisseria meningitidis should be administered to all patients who have, or will have, a cochlear implant and should be also recommended to all other individuals who have an abnormal communication between the middle and inner ears. The pneumococcal conjugate vaccine is also moderately effective in reducing the attack rate of otitis media, especially in children who have recurrent episodes. 5
  5. Because otitis media is the most likely antecedent event in the pathogenesis of labyrinthitis and meningitis in patients who have a middle and inner ear defect, surgical repair is indicated. If cochlear implant surgery is planned, the repair can be performed at the time of the implantation if feasible. 2

In the past meningitis, especially recurrent attacks, associated with inner ear abnormalities was considered to be a rare occurrence, but we now have the cumulative outcomes of children from around the world who received cochlear implants that the incidence of this suppurative complication is relatively high. Timely referral of patients who are suspected of having an inner ear malformation to the otolaryngologist is an important step in prevention of meningitis in these infants and children. Long term follow-up should be a team effort between the primary care physician and the otolaryngologist.

Charles D. Bluestone, M.D.

1. Newsletter: cochlear implants and meningitis. Pediatr Infect Dis J 2002; 21 ( 10).
2. Bluestone CD. Prevention of meningitis: cochlear implants and inner ear abnormalities. Arch Otolaryngol Head Neck Surg 2003; 129: 279–81.
3. FDA Public Health Web Notification: cochlear implant recipients may be at greater risk for meningitis. July 24, 2002; updated: August 15, 2002; October 17, 2002. Available at: http://www.fda.gov/cdrh/safety/cochlear.html.
4. O’Donoghue G, Balkany T, Cohen N, et al. Meningitis and cochlear implantation. Otol Neurotol 2002; 23: 823–4.
5. Fireman B, Black SB, Shinefield HR, et al. Impact of the pneumococcal conjugate vaccine on otitis media. Pediatr Infect Dis J 2003; 22: 10–16.
Keywords:

Meningitis; cochlear implants

© 2003 Lippincott Williams & Wilkins, Inc.