Acute mastoiditis in children: a 10-year retrospective and validated multicenter study.

BACKGROUND: Conservative treatment of acute otitis media may lead to more complications. This study evaluates changes in incidence, the clinical and microbiological findings, the complications and the outcome of acute mastoiditis in children in a country employing conservative guidelines in treating acute otitis media.
METHODS: All admitted children (0-15 years) diagnosed with acute mastoiditis during the period from 1998 to 2007 in eastern Denmark (population 2.2 million) were identified. Patient files were retrieved and reviewed; the data were entered into a database.
RESULTS: The average incidence of admitted children with acute mastoiditis was 4.8/100,000 children per year (95% CI were ± 0.03 -0.04), and there was no change in the incidence during the 10-year period. Of the 214 children included (mean age 2.1 years, range 0.3-13.1, median 1.3 years), 100% presented with protrusion of the pinna and 95% with retroauricular swelling and redness, whereas 32% had a retroauricular abscess. Mastoidectomy had been performed in children with a retroauricular abscess. Thirty-one percent had a ventilation tube inserted. The remaining group was treated with antibiotics and analgesics, and 86% also had a myringotomy performed. Streptococcus pneumoniae and group A streptococci were the bacteria most commonly cultured, 94% being susceptible to penicillin. The complication rate was low at 1.9%. All children included were initially admitted; no patients were outpatients.
CONCLUSIONS: The incidence of acute mastoiditis is stable in eastern Denmark where conservative management guidelines for treating acute otitis media are used. Bacterial resistance toward penicillin is low (6%), complications are rare and the treatment outcome is good. Furthermore, no severe complications after treatment were observed.