Topical treatment of chronic suppurative otitis media in Aboriginal children.

In Aboriginal children, chronic suppurative otitis media (CSOM) is a serious health problem, particularly in the remote areas of Australia. According to the World Health Organization (WHO), CSOM may be seen in more than 34% of children in a given population. (1) Another possible sequela is a serious intracranial complication. CSOM is a disease of poverty related to poor living conditions, a lack of good water and hygiene, overcrowding, early exposure to infection, and poor access to medical care--all factors that apply to Aboriginal children. (2) The federal government of Australia recently published national clinical management guidelines on behalf of the National Aboriginal Community Controlled Organisation (NACCHO). (3)

For the past 30 years, the mainstay of treatment for discharging ears in the Aboriginal population has been ear toilets or dry ear swabbing followed by administration of antibiotic eardrops. The standard drops that have been used are made up of 0.5% neomycin B (framycetin), gramicidin, and dexamethasone. However, this combination is potentially ototoxic. Dry ear swabbing has been found to be ineffective,a so the current best-practice management entails the use of 0.005% povidone iodine (a 5% solution of 10% povidone iodine) followed by drying of the external ear canal with tissue spears and administration of antibiotic eardrops by a tragal pressure injection technique.

Many studies have shown that the nonototoxic quinolones are more effective than other ototopicals in the management of CSOM. (4) However, until recently, no comparison of ototopical therapy had been conducted in Aboriginal children. The recent NACCHO eardrop trial was the first to do so.

The NACCHO eardrop trial

The NACCHO trial was a community-based, multicenter, randomized, controlled, double-blind study to compare the efficacy of topical ciprofloxacin/hydrocortisone with that of neomycin B/gramicidin/dexamethasone drops in the management of CSOM in Aboriginal children. This study was conducted in eight Aboriginal communities located in the northern parts of Western Australia and Queensland. The NACCHO board of directors recruited Aboriginal children younger than 15 years who were diagnosed with CSOM (defined by the WHO as otorrhea of more than 2 weeks' duration).

Patients were assigned to receive either topical 0.3% ciprofloxacin combined with hydrocortisone or topical 0.5% neomycin B combined with gramicidin and dexamethasone. All patients received 5 drops twice daily for 9 days. Prior to drop therapy, 0.005% povidone iodine solution was used as an ear toilet to clear the otorrhea. Also, data on each patient's history, epidemiology, and bacteriology with accompanying video-otoscopic and audiometric findings were obtained at baseline. Aboriginal health workers measured primary outcomes in terms of the degree of reduction of otorrhea at 10 and 14 days; secondary outcomes included changes in tympanic membrane perforation status and improvements in hearing. Bacteriology was performed and bacterial resistance studies were conducted. The results of this study are being prepared for publication in The Medical Journal of Australia.

In accordance with WHO regulations, nonototoxic ototopical drops in CSOM in Aboriginal children should be the first line of therapy because of their efficacy and lack of ototoxicity.

Biofilm

I recently isolated bacterial biofilm in the middle ear mucosa of an Aboriginal child with CSOM. This finding represents perhaps the first instance of biofilm being isolated in a normal middle ear structure in a child. This discovery has important implications for the development of substances to break down the biofilm's defenses and thus allow for subsequent enhancement of treatment with a quinolone ototopical agent.

References

(1.) WHO/CIBA Foundation. Prevention of hearing impairment from chronic otitis media. Presented at a WHO/CIBA Foundation Workshop: Nov. 19-21, 1996; London.

(2.) Coates HL, Morris PS, Leach AJ, Couzos S. Otitis media in Aboriginal children: Tackling a major health problem. Med J Aust 2002;177:177-8.

(3.) Morris PD, Ballinger D, Leach A. et al. Recommendations for clinical care guidelines on the management of otitis media in Aboriginal and Torres Strait Islander populations. Canberra: Office of Aboriginal and Torres Strait Islander Health, 2001.

(4.) Acuin J, Smith A, Mackenzie I. Interventions for chronic suppurative otitis media (Cochrane Review). In: The Cochrane Library, Issue 2, 2002. Oxford: Update Software.