Barotitis

DESCRIPTION

Injury to the middle ear, or less commonly the inner ear, caused by changes in atmospheric pressure; most often caused by air travel or scuba diving but can occur via any other means of rapid altitude change, such as in an elevators
In general, it is the descent from a zone of relative low atmospheric pressure (e.g., plane in sky or diver on water’s surface) to a higher pressure (plane on ground or diver at depth) that causes injury.
People often experience popping sounds (and less commonly mild discomfort) with ascent, but ascent rarely causes barotrauma.
Barotitis may also be caused by the pressurization phase in a hyperbaric oxygen chamber, by explosions, and when “slapped” in the ear by an open hand or a surface such as when a falling water skier strikes the water ear first.

Severe disease rarely occurs on commercial aircraft because pressurization allows gradual pressure changes.
Significant disease is more common in scuba divers, in those who fly military aircraft, and during use of hyperbaric oxygen chambers.
There is a wide variation in severity ranging from brief and mild otalgia, secondary to delayed pressure equilibration across the eustachian tube, to rupture of the tympanic membrane (TM) or, the most severe, rupture on inner ear membranes.
Studies reporting an incidence of mild self-limiting discomfort for up to 55% for children and 20% of adults after a single flight
40% of scuba divers experience some degree of otalgia, and it is more likely to be severe if they continue to descend without pausing to reequilibrate their middle ear pressures.

Mild pressure differential will cause only self-limiting pain.
Higher pressure may cause hemotympanum (bruising of eardrum) or a middle ear effusion, often of serosanguineous nature.
With enough pressure differential, the eardrum may rupture.
Rarely, the eardrum will stay intact, and instead either the round or oval windows (which divide the air-filled middle ear from the fluid-filled inner ear) will rupture. This is a devastating event, which usually results in permanent hearing loss.

Age: Infants or toddlers are at higher risk because of smaller, less vertical eustachian tubes, and their propensity for nasal inflammation.
Conditions that impair eustachian tube function including otitis media, upper respiratory tract infection (URI), allergic rhinitis
Smoking
Past history of middle ear disease.

Gradual descent during scuba diving, pausing to reequilibrate middle ear pressures before experiencing ear discomfort
Gentle Valsalva maneuver—overly vigorous autoinflation could produce the trauma it is intended to prevent.
Divers should descend feet first to keep the eustachian tube in a more functional position.
Yawning, swallowing, chewing, or doing Valsalva maneuver during descent of airplanes before ears start to hurt
The beginning of descent in an airplane is a good time for infants to nurse or take a bottle. Sucking a pacifier without swallowing is of no benefit.
Avoid flying or diving when experiencing URI or allergic rhinitis symptoms.
Avoid sleeping on plane during descent.

Boyle’s law states that as the pressure of a gas decreases, volume increases, and as pressure of a gas increases, volume decreases.
Ambient pressure decreases during airplane/scuba diving ascent and increases during descent.
During ascent, the TM bulges outward and the eustachian tube vents the excess middle ear pressure. Pressure is easily equalized.
During descent, the TM bulges inward and the eustachian tube resists the inward flow of air. Pressure equalization is difficult.
- At a pressure differential of 60 mm Hg (greater ambient to middle ear pressure), subjective discomfort is reported.
- At a pressure differential of 90 mm Hg, the eustachian tube collapses and becomes so obstructed that autoinflation may become unsuccessful.
- TM can rupture at pressure differentials >100 to 400 mm Hg.
Barotitis is sometimes classified using Teed classification of disease severity (see “Physical Exam”).