Written by Darla Burke | Published on June 20, 2012
Medically Reviewed by Brenda B. Spriggs, MD, MPH, FACP

What Is Mastoid Bone Infection of the Skull?

One of the most important structures in your inner ear is the mastoid bone. Although it’s called a bone, the mastoid does not have the typical structure associated with bones in the human body. Rather than being solid and rigid like most bones, the mastoid bone is made out of air sacs and resembles a sponge.

To function properly, the mastoid must receive air from other parts of the ear, including the Eustachian tube. Your Eustachian tube connects your middle ear to the back of your throat. If an infection develops in your middle ear and your Eustachian tube is blocked, it may cause an infection in the mastoid bone. This serious infection is known as mastoid bone infection of the skull, or mastoiditis.

What Causes Mastoid Bone Infection of the Skull?

The most common cause of mastoiditis is a middle ear infection that has been left untreated. If the infection is not eliminated, it can spread to the inner ear, invading the sacs of the mastoid bone. When this occurs, the mastoid bone may begin to disintegrate.

Although the condition is most common in children, it can also occur in adults. The number of cases of mastoiditis has decreased significantly since the discovery of antibiotics in the early 1900s. Before antibiotics, mastoiditis was a leading cause of death among children.

What Are the Symptoms of Mastoid Bone Infection of the Skull?

The symptoms of mastoiditis are similar to those of an ear infection. They include:

  • drainage from the affected ear
  • ear pain
  • fever
  • headache
  • hearing loss in the affected ear
  • redness, swelling, and tenderness in the affected ear

In some cases, mastoiditis may result in the development of a brain abscess or other complications involving the skull. The symptoms of these conditions include severe headaches and swelling behind the eyes. This swelling is known as papilledema.

How Is Mastoid Bone Infection of the Skull Diagnosed?

If you have symptoms of an ear infection, your doctor will examine your ears and head to determine if the infection has spread to your mastoid bone.

The mastoid bone is located in the inner ear and may not be visible due to the infection. Therefore, your doctor may perform other tests to confirm the diagnosis. These include:

  • a white blood cell count to confirm the presence of an infection
  • a CT scan of your ear and head
  • an MRI scan of your ear and head
  • an X-ray of your skull

If the tests confirm a diagnosis of mastoiditis, your doctor may also perform a lumbar puncture (spinal tap). This test will allow your doctor to determine if the infection has spread to your spinal column.

How Is Mastoid Bone Infection of the Skull Treated?

Mastoiditis is a potentially life-threatening condition. If the infection is severe, initial treatment may include hospitalization. While in the hospital, you will receive antibiotic medication through a vein in your arm (intravenously). After you are released from the hospital, you will be required to take oral antibiotics at home for several days.

If the infection does not clear up after treatment with antibiotics, surgery may be required. Surgery may involve removing part of your mastoid bone so that the infection can be drained. Your middle ear may also need to be drained of infected fluid to successfully treat the infection.

Complications Associated with Mastoid Bone Infection of the Skull

Treatment of mastoiditis can be difficult because the mastoid is located deep inside your ear. If treatment is not effective or if the infection is not treated before the mastoid is damaged, serious health problems may result. These include:

  • vertigo (dizziness)
  • facial paralysis
  • hearing loss
  • meningitis (a bacterial infection of the membranes covering your brain and spinal chord)
  • epidural abscess (a collection of pus on the outside of your brain and spinal chord)
  • sepsis (spreading of the infection throughout your body)

Outlook for Patients with Mastoid Bone Infection of the Skull

If mastoiditis develops, early intervention is necessary to prevent permanent damage. Even if treatment is successful, the infection may return. Patients who develop mastoiditis will need to be monitored by their doctors to ensure that the infection does not return or spread.

How Can Mastoid Bone Infection of the Skull Be Prevented?

Mastoiditis can be prevented by effectively treating all ear infections. If you develop an ear infection, seek prompt medical attention and follow your doctor’s advice. This may include taking oral antibiotics for seven to 10 days.

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