The mastoid process is a sponge-like bone behind the ear. The outer part of the mastoid process is comprised of dense bone and the inner part is filled with tiny interconnecting air sacs. Several neck muscles attach to the mastoid process, including the sternocleidomastoid. The mastoid process and the middle ear communicate with each other. The most superior part of the middle ear cavity, the epitympanic recess, communicates with the mastoid process via the mastoid antrum. Infection of this bone is called mastoiditis. Mastoiditis is common in children; however, it can also affect adults.
Table of contents
Due to the anatomical connection between the middle ear cavity and the mastoid process, the most common cause of mastoiditis is a middle ear infection which has been untreated and spread to the mastoid process. Another less common cause of mastoiditis is cholesteatoma. Cholesteatoma is an abnormal skin growth that forms behind the tympanic membrane (ear drum) which can impair the drainage of the middle ear, which can then lead to mastoiditis.
Mastoiditis is typically a bacterial infection. The bacteria implicated mirror those which are implicated in ear infections. Common causative bacteria include:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
Bacteria that are less commonly implicated include staphylococcus aureus and pseudomonas.
Common signs and symptoms of mastoiditis include:
- Pain, tenderness, erythema and swelling behind the ear
- Earache/ear pain
- Hearing loss – the sensation of having a blocked ear
- Loss of appetite
- Discharge from the ear
Antibiotics are the main treatment used for mastoiditis; however, surgery may be necessary in some cases. If there is a discharge present from the ear, this is usually swabbed and cultured to find out the causative bacteria, and which antibiotics will be effective to eradicate the infection. The antibiotics are usually given intravenously, which may require hospitalisation.
Sometimes a surgical procedure is performed to help drain the fluid from the middle ear cavity; this is called a myringotomy. This involves creating a small hole in the tympanic membrane to help the fluid behind it to drain. Often, a grommet will be inserted at the same time. In severe infections which do not respond to the aforementioned treatments, a surgical procedure to remove the entire mastoid process may be performed; this is referred to as mastoidectomy. Mastoidectomy is important to prevent some of the serious, life-threatening complications which can occur as a result of mastoiditis (discussed below).
The most effective method of preventing mastoiditis is to seek treatment for ear infections early. It is also important to take the course of antibiotics as directed, and to finish the entire course, even if your symptoms resolve. Taking the course as directed helps to both prevent recurrences, and, crucially, decreases the likelihood of antibiotic resistance developing.
If left untreated, mastoiditis can have serious complications. The chances of complications developing are reduced if treatment is sought early and that the treatment regime is adhered to. Some of the possible complications of mastoiditis include:
- Hearing loss
- Paralysis of parts of the face
If you have any other questions about ear infections and mastoiditis make an appointment to see our ear nose and throat specialist.