Recurrent acute mastoiditis - a retrospective national study in Sweden.

CONCLUSIONS: Recurrences were seen in 5% of all patients with acute mastoiditis (AM). Mastoidectomy had been performed in the majority of the patients with recurrences at their first episode of AM. Compared with the group with a single episode of AM, the recurrent group exhibited more subperiosteal and ear canal abscesses, although they were not more severely ill. It appears from this study that previous mastoidectomy itself could predispose patients to recurrent AM (rAM), perhaps due to easier access to the mastoid cavity and/or due to a reduction in mucosal lining.

OBJECTIVE: To retrospectively study the incidence and characteristics of rAM in Sweden.

METHODS: Data from patients with rAM were reviewed and compared with data from patients with a single episode of AM during 1993-2007 in 33 ear, nose and throat departments in Sweden.

RESULTS: Of 798 cases fulfilling the criteria for AM, 36 patients (5%) had experienced one or more recurrences, of which 4 patients (11%) had concurrent cholesteatoma. More than 50% of the patients had their first episode of AM before the age of 2 years. There was a highly significant difference between the two groups concerning the frequency of mastoidectomies and subperiosteal/retroauricular abscesses. However, other clinical characteristics, including severe complications, did not differ significantly. The majority of recurrences were treated conservatively with myringotomy and intravenous antibiotics, and also with aspiration/incision if a subperiosteal/retroauricular abscess was present.