M

mastoiditis An INFECTION in the mastoid BONE
behind the EAR. Mastoiditis typically develops as a
consequence of untreated or chronic OTITISmedia
(middle ear infection) when BACTERIA migrate
from the middle ear to the adjacent mastoid bone.
The rather porous structure of the mastoid bone,
which is more a collection of small cavities than a
solid structure, provides an ideal habitat for bacte-
ria. Untreated mastoiditis can spread to the nasal
SINUSESas well as the MENINGES(membranes sur-
rounding the BRAINand SPINAL CORD), causing bac-
terial MENINGITIS, and to the brain itself, causing
ENCEPHALITIS. These infections are potentially fatal
and require immediate medical treatment. Though
mastoiditis was once a common cause of child-
hood death, it has become rare since the advent of
ANTIBIOTIC MEDICATIONS.
PAINbehind the ear, FEVER, and a recent episode
of otitis media are the leading indications of acute
mastoiditis. The person may also have swelling
and tenderness in the mastoid area, and the auri-
cle (external ear) may appear to stick out from the
side of the head. Chronic mastoiditis may be sub-
clinical; that is, the infection causes few overt
symptoms until it spreads beyond the mastoid or
destroys mastoid bone tissue. Diagnosis includes
blood tests and cultures of any fluid in the ear to
look for signs of infection, and occasionally COM-
PUTED TOMOGRAPHY(CT) SCAN. In most cases of acute
mastoiditis, antibiotic medications and occasion-
ally MYRINGOTOMY (insertion of a small tube
through the TYMPANIC MEMBRANEto allow fluid to
drain from the middle ear) successfully eradicate
the infection. Chronic mastoiditis sometimes
requires surgery to open, drain, and occasionally
remove portions of the mastoid structure. Severe
mastoiditis may require mastoidectomy, in which

the surgeon removes the entire mastoid bone.

Most people recover fully following treatment,

though should have an AUDIOLOGIC ASSESSMENTto

determine whether there is residual HEARING LOSS.

See also ABSCESS; SURGERY BENEFIT AND RISK

ASSESSMENT.

Ménière’s disease A disorder of the inner EAR

that results in balance and hearing disturbances.

Doctors do not know for certain what causes

Ménière’s disease. There are numerous approaches

to treating the condition’s symptoms though there

is no known cure for the disease. The most signifi-

cant consequence of Ménière’s disease is perma-

nent and progressive HEARING LOSS. About 2.5

million Americans have Ménière’s disease.

The disease is also called endolymphatic

hydrops, a reference to the dilation of the struc-

ture in the inner ear called the membranous

labyrinth. Researchers believe the dilation signals

an abnormal accumulation of fluid within the

membranous labyrinth, though do not know what

causes that accumulation. Current research sug-

gests that the dilation results in small tears that

allow the fluid within the membranous labyrinth,

the endolymph, to mix with fluid outside the

membranous labyrinth, the perilymph. The two

fluids have different chemical compositions; some

researchers believe changes in the electrolyte con-

tent that occur when the fluids mix cause vestibu-

lar dysfunction that results in the specific

constellation of symptoms that define Ménière’s

disease. Continued or repeated dilation likely

results in repeated tears and recurrent symptoms.

Symptoms and Diagnostic Path

Most otolaryngologists look for four cardinal, or

defining, symptoms that occur with repeated

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