Encyclopedia of Health and Medicine

B
barotrauma Damage to the structures of the EAR
resulting from the ear’s inability to equalize pressure
with abrupt and extreme changes in atmospheric
pressure. Such changes most often occur in
situations of sudden altitude change such as air
travel or diving, though also may result from a
sharp blow to the ear that forces a blast of air into
the auditory canal. Any of the three parts of the
ear—outer, middle, and inner—can experience
injury from barotrauma.
• Outer ear barotrauma typically takes the form
of small, painful blisters and hemorrhages
along the walls of the auditory canal.
• Middle ear barotrauma commonly includes a
ruptured TYMPANIC MEMBRANE (eardrum). The
pressure within the middle ear can become
intense before the tympanic membrane gives
way, causing much PAIN. With rupture the pressure
immediately equalizes, though hearing
ability temporarily diminishes.
• Inner ear barotrauma causes sudden and usually
significant VERTIGO (extreme dizziness and
balance disturbances) and HEARING LOSS that can
be permanent.
Most outer and middle ear barotrauma heals on
its own. Many ruptured eardrums heal naturally,
though large or irregular tears require surgical
repair (TYMPANOPLASTY). Inner ear barotrauma may
require surgery to repair damaged structures and
may result in permanent functional loss if the
damage is extensive.
Preventive measures to reduce the likelihood of
barotrauma include chewing gum, frequent swallowing,
and yawning during activities that involve
changes in barometric pressure such as descending
during air travel. Some people benefit from nasal
decongestant sprays that clear the nasal passages
and eustachian tubes. Recreational divers are at
greatest risk for inner ear barotrauma; pressure
changes are most drastic nearer the surface than
deep in the water.
See also BLISTER; EUSTACHIAN TUBE; HEMORRHAGE.
benign paroxysmal positional vertigo (BPPV) A
disorder of the inner EAR in which certain positions
of the head cause sudden and severe, though
brief, episodes of VERTIGO (sensations of spinning
or motion). Many people experience symptoms
upon awakening from sleep, as they roll from one
position to another or tilt their heads. Though the
vertigo episode typically lasts only a few minutes,
it can result in feelings of NAUSEA and dizziness as
well as balance disturbances, that continue for
several hours.
Doctors believe calcifications called otoconia,
small “stones” of calcium carbonate, cause BPPV.
Otoconia occur naturally in the utricle and saccule,
two of the structures within the inner ear
that are part of the vestibular system, the body’s
balance mechanisms. When otoconia escape from
the utricle they can enter the semicircular canals,
where they collide with NERVE endings that send
positional messages to the BRAIN. These collisions
overwhelm the messaging network. The otoconia
tend to dissolve in the inner ear fluid over time.
About half the people who develop BPPV
experience head trauma or serious INFECTION, such
as OTITIS (ear infection) or SINUSITIS (sinus infection),
before BPPV symptoms begin, leading doctors
to believe that such assaults on the integrity
of the inner ear jars the otoconia out of the
utricle.
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