Mastoiditis

Timothy C. Hain, MD Page last modified: February 7, 2010

DEFINITIONS

Mastoiditis is an inflammation or infection of the sinus behind the middle ear (Mastoid sinus). This can be often seen on imaging studies such as MRI (see below).

Right sided mastoiditis (white blotch on the left side of this image). On MRI films, the right side of the head is shown on the left side of the image.

There are several types of Mastoiditis

• Noncoalescent mastoiditis
  • MRI findings of fluid in mastoid -- not necessarily infectious
  • AOM plus swollen or protruding ear
• Coalescent mastoiditis (destruction of bony trabeculae or cortex of temporal bone)

Severe mastoiditis is characterized by a swollen external auditory canal. Mild mastoiditis, may be silent, and only seen on imaging (as above).

There are several treatment approaches --

• Observation - -this is appropriate when there is only fluid in the sinus. Often observation is combined with attempts to open the eustachian tube.
• Antibiotics similar to those used for other types of sinusitus. Levoquin and trimethoprim sulfa are commonly used, for a month or more.
• Myringotomy -- means cutting a hole in the ear drum. This procedure may be done to drain pus from the middle ear, obtain material for culture, and aerate the middle ear.
• Mastoidectomy -- means opening up the mastoid sinus.
  • This is a procedure used for hospitalized patients whose otitis media with mastoiditis does not respond to IV antibiotics.
• PE tubes may be helpful in mild cases but they do not provide adequate drainage for severe cases of mastoiditis. PE tubes tend to be used in more chronic situations than myringotamy

Meredith and Boyev (2008) recently wrote on mastoditis on MRI, and suggested that the term is most often applied to the observation of fluid in the mastoid, which may be clinically insignificant. Neverthless, they note that the literature indicates that only 4/1000 temporal bones have fluid on MRI in the mastoid in asymptomatic volunteers, and in TMJ MRI, only 10 patients had fluid out of 2700. This would seem to suggest that fluid in the mastoid is generally rare. It has been our observation that in our dizziness and hearing practice in Chicago, at least 1/100 of our patients has mastoid fluid. This suggests to us that mastoiditis may be a cause of dizziness or heaing symptoms. Alternatively, it may be much more common in Chicago than reported in general (seems unlikely to us).

Facial paralysis associated with mastoiditis

An acute lower motor neuron facial palsy (Bells palsy) is rare even though dehiscence of the facial canal is very common. When this happens, there should be a myringotomy with PE tube placement, Infectious disease consultation, intravenous antibiotics, and consideration of mastoidectomy. Once the infection resolves, facial nerve function usually recovers over several months.

Labyrinthitis associated with mastoiditis

This comes in several stages.

• Serious labyrinthitis - -bacterial toxins enter the inner ear and cause vertigo and mild hearing loss.
• Purulent labyrinthitis occurs as bacteria enter the inner ear.
• Labyrinthitis ossificans -- occurs when the inner ear fills with scar tissue

In patients believed to have labyrinthitis associated with AOM, one should image the brain, obtain a lumbar puncture, place a PE tube, administer IV antibioitics, and consider mastoidectomy.

Gradenigo's syndrome (Petrous apicitis)

The symptoms of this include severe frontal headache, eye pain, diplopia, dizziness, nausea, and 6th nerve palsy. There should be otitis media seen on otoscopy. MRI shows inflammation of the petrous apex and mastoids. CT may show bone erosion in the petrous apex.

Treatment is with myringotomy with PE tube, and culture-directed IV antibiotic therapy.

Mimickers of mastoidits

• Rhabdomyosacroma
• Langerhans cell histiocytosis

References

• Meredith JR, Boyev KP. Mastoiditis on MRI: Fact or artifact ? ENT journal, Sept 2008, 514-518