Hello, Welcome to HCM, Mastoiditis is a bacterial infection of the mastoid bone, which consists of air spaces that help to drain the middle ear. When the mastoid cells become infected or inflamed it will land up in unresolved middle ear infection. Mastoiditis often develops as a result of a middle ear infection Mastoiditis can be treated by 1.Eardrops, and regular ear cleaning by a doctor. 2.Oral antibiotics, 3.If these treatments do not work, surgery may be necessary to prevent further complications. Myringotomy can done to drain the fluid accumulated in the middle ear. Thank you.