What is mastoiditis?
Mastoiditis in an infection of the mastoid bone that lies behind the ear. It usually occurs as an extension of acute otitis media (a middle ear infection).
What causes it?
The mastoid bone is connected to the middle ear space, so a middle ear infection can spread to the mastoid bone and cause a mastoiditis. Read more about the structure of the middle ear and mastoid bone here.
What are the symptoms?
Mastoiditis causes pain, redness and swelling behind the ear. Typically, the ear is pushed outwards and downwards away from the head. It is usually accompanied by high fever and the feeling of being very run down and ill (called malaise). Often there have been symptoms of a middle ear infection before the mastoiditis develops.
How is it diagnosed?
The diagnosis is usually readily made based on the symptoms and examination of the ear. There may be a history of middle ear infections in the past as well. The history and examination are usually enough to make a plan for treatment.
What are the risks of mastoiditis?
Mastoiditis is still a potentially serious condition. The infection in the mastoid bone can develop into an abscess (a collection of pus). This can then spread from the ear and into the face or down the neck. Infection from the infected mastoid bone can also spread into the brain and cause meningitis or a brain abscess. With the availability of antibiotics these days, however, these risks are rare. Even so, it is important that treatment is started as soon as possible.
What is the treatment?
Mastoiditis usually requires admission to the hospital for treatment with intravenous antibiotics, pain relief and fluid hydration. Most children will start to show improvement within 24 to 48 hours after which the they can be discharged home with oral antibiotics for a week. Most children will resolve without the need for surgery.
If after 24 to 48 hours of treatment there has been no change in the symptoms, a CT scan of the ear is performed to look for the presence of an abscess. If an abscess is found, then this must be treated with an operation. A hearing test is usually performed before any ear operation.
There are two ways of surgically treating a mastoid abscess. The traditional way involves making an incision behind the ear to drain the abscess and performing a cortical mastoidectomy, which is a removal of the bone of the mastoid down to the middle ear with a drill, to allow for full drainage of the pus and to prevent further collection. Often, a ventilation tube (grommet) is also placed across the ear drum. The surgery is performed under a general anaesthetic. A plastic drain is usually placed behind the ear for 24 to 48 hours and then removed on the ward just before the child is discharged home with oral and topical (drops) antibiotics for a week.
Recent research has shown that a mastoid abscess can be surgically managed without the need for a cortical mastoidectomy in the first instance. Instead, the abscess is drained either with a more limited incision behind the ear or aspirated with a needle and then a grommet is placed across the ear drum. This is also performed under a general anaesthetic. The outcomes of this technique has been shown to be the same as those for the traditional technique, but the advantages are less surgical risk to the ear and a potentially shorter hospital stay. The disadvantage is that there is a higher risk of recollection of the abscess. If this occurs, then a traditional approach is undertaken as a second procedure.
The approach that is used is determined on a case by case basis. Any complications that arise because of a mastoid abscess will also be treated as appropriate on a case by case basis.
What is the follow-up after treating mastoiditis?
Once the child has been discharged from the hospital, he or she is usually followed up in the clinic in 1 week to make sure that the mastoiditis has fully resolved. Further management will depend on whether there has been a history of recurrent middle ear infections or not. In children who have had a recent history of this, then grommet insertion may be considered as an elective procedure to prevent further episodes of middle ear infection and a potential recurrence of mastoiditis.
If the child has had a mastoid abscess drained, then more than likely a grommet would have been placed at the time of surgery and follow-up will be routine as in any child who has received grommets.
Read more about grommet insertion here.
A picture of a child with a left-sided mastoiditis causing swelling and redness behind the ear with protrusion of the ear away from the head.
This child has a right mastoiditis which is also causing protrusion of the ear outwards and downwards from the head.