Acute mastoiditis - the antibiotic era: a multicenter study

Objectives: To evaluate the clinical course and identify the causative orga nisms of acute mastoiditis in a community where most of the patients who de velop acute otitis media are treated with antibiotics. Methods: A multicent er retrospective review of a series of 223 consecutive cases of acute masto iditis. Setting: Nine secondary or tertiary academic or non-academic referr al centers. Results: Prior to the diagnosis of acute mastoiditis, 121 of th e patients (54.3%) had been receiving oral antibiotic treatment for acute o titis media for periods ranging from 1 to 21 days (mean 5.3 days). Samples for bacterial culture were obtained from 152 patients. Cultures were negati ve in 60 patients. The organisms isolated in the 92 positive cultures were: Streptococcus pneumoniae (15 patients), Streptococcus pyogenes (14 patient s), Staphylococcus aureus (13 patients), Staphylococcus coagulase negative (three patients), Pseudomonas aeruginosa (eight patients), Haemophilus infl uenzae (four patients), Proteus mirabilis (two patients), Escherichia coli (two patients), Klebsiella pneumoniae (one patient), Enterobacter (one pati ent), Acinetobacter (one patient), anaerobic gram-negative bacilli (one pat ient), and fungi (two patients). Ten patients had mixed flora. Sixteen pati ents presented with complications (cerebellar abscess, perisinus empyema, s ubdural abscess or empyema, extradural abscess, cavernous sinus thrombosis, lateral sinus thrombosis, bacterial meningitis, labyrinthitis, petrositis, or facial nerve palsy). Conclusions: Antibiotic treatment cannot be consid ered an absolute safeguard against the development of acute mastoiditis. Ea rly myringotomy for acute otitis media seems to decrease the incidence of c omplications. The distribution of causative organisms in acute mastoiditis differs from that in acute otitis media. Intracranial complications in acut e mastoiditis are not rare. Because of the diversity of causative organisms in acute mastoiditis and the growing resistance of bacteria to the various antibiotics, all means to obtain a sample for culture prior to antibiotic treatment, including general anesthesia. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.