Mastoiditis

Definition of Mastoiditis

Mastoiditis is an inflammation within the mastoid portion of the temporal bone. The temporal bone forms the side of the skull, and its temporal portion is that part immediately behind the ear. Mastoiditis is usually caused by an infection.

What is going on in the body?

Inflammation that starts in the mastoid itself is quite rare. Mastoiditis is almost always caused by an infection in the middle ear, which is behind the eardrum. Because the mastoid is close to the middle ear, it is easy for middle ear infections, such as acute otitis media, to spread to the mastoid.

Long-lasting (chronic) mastoiditis lasts for more than 3 months. Acute or shorter-lasting mastoiditis lasts less than 3 weeks.

What are the signs and symptoms of the disease?

Signs of mastoiditis may include:

• fever
• pain behind the ear
• infected drainage coming through a hole in the eardrum
• a red and swollen lining of the middle ear
• some degree of hearing impairment

Other signs are usually only seen with acute mastoiditis. These may include:

• swelling and redness of the skin behind the ear
• significant swelling behind the ear that causes the ear to be pushed forward
• a soft, compressible feeling to the bone behind the ear. This means that there is an abscess, a pocket of pus, under the skin.

Chronic mastoiditis does not produce changes over the bone behind the ear. Most of the time, a person with chronic mastoiditis has no symptoms other than occasional pain. When the condition flares up, pus can drain from the ear canal.

What are the causes and risks of the disease?

The main cause of acute mastoiditis is untreated or incompletely treated middle ear infection (acute otitis media). The main cause of chronic mastoiditis is a perforated eardrum combined with a long-lasting infection in the middle ear, known as chronic otitis media.

Benign ear growths, particularly cysts known as cholesteatomas, are also frequent causes.

What can be done to prevent the disease?

Antibiotics for ear infections and methods to drain fluid from the ears can help prevent most cases of mastoiditis. It is important that a person take the full course of the antibiotic to prevent mastoiditis. Also, children who have frequent infections should be monitored in an effort to prevent mastoiditis and ear cysts from developing.

How is the disease diagnosed?

To make the diagnosis, the healthcare professional first examine the person's ear with an otoscope. The professional may then order x-ray tests or a CT scan.

If the infection is severe, the x-ray tests will show damage or infection of the bone. A CT will demonstrate similar changes but gives a more complete picture of the anatomy of the bone and other middle ear structures.

What are the long-term effects of the disease?

Acute mastoiditis can be complicated by:

• material under the skin behind the ear
• facial paralysis
• nerve deafness or hearing impairment
• vertigo or dizziness
• meningitis, or inflammation of the lining of the brain, which may cause permanent brain damage or death
• a blood clot in the veins that drain the blood from the brain
• an abscess or pocket of pus under the skin, in nearby muscles, or even in the brain. A brain abscess can result in permanent brain damage or death.
• scarring in the ear or mastoid

What are the risks to others?

There are no risks to others, as the condition is not contagious.

What are the treatments for the disease?

Treatment for acute mastoiditis includes the insertion of an ear tube through the eardrum to allow drainage of infected fluid. A cut can also be made in the eardrum for the same purpose. If there is a collection of pus under the skin behind the ear, it may need to be drained.

The first step in treating chronic mastoiditis is oral or topical antibiotics. If these do not clear up the problem, surgery is needed to remove the diseased part of the mastoid and repair the eardrum. If an ear cyst exists, the cyst is removed and the eardrum repaired. If the bones of the middle ear have been damaged, they will be repaired as well.

What are the side effects of the treatments?

Placement of the drainage tubes can result in complications such as long-lasting holes in the eardrum, ear drainage, and rarely, deafness. Side effects from surgery to remove the mastoid can include damage to nearby structures such as:

• facial paralysis from injury to the facial nerve
• hearing impairment from damage to the bones or nerves in the ear that aid in hearing
• vertigo from damage to the ear's balance system

What happens after treatment for the disease?

Most cases of acute mastoiditis clear up once the ear tube is inserted and antibiotics are started. The tube is left in until it falls out by itself, usually within 6 to 12 months. If surgery for chronic mastoiditis is successful, the hole in the eardrum will heal closed. The person's hearing will improve, though it may not completely return to normal in some cases. The ear will stop draining.

How is the disease monitored?

An new or worsening symptoms should be reported to the healthcare professional.