TORONTO -- The hearing condition that has caused Quebec pop star Celine Dion to cancel some upcoming Las Vegas shows is known as Patulous eustachian tube. So just what is it and why does it occur?
Patulous eustachian tube is a disorder in which the channel that runs between the middle ear and back of the nose and throat stays open. Normally, these eustachian tubes remain closed and open only occasionally to regulate air pressure around the ear drum. A valve near the opening into the middle ear controls this process.
Sneezing, swallowing or yawning causes the valve to open, which keeps air pressure and fluid from building up inside the ears. Descending in an aircraft can also affect the function of the valves and eustachian tubes, leading to a pressure build-up that muffles hearing and sometimes causes pain.
Dr. Vincent Lin, a surgical otologist at Sunnybrook Health Sciences Centre in Toronto, said the exact cause of Patulous eustachian tube is unknown.
"We know that there's a little bit of fat around the valve and people who, for example, lose a massive amount of weight will also lose fat," he said Thursday. "And that fat pad, if you lose a lot of weight, it can almost pull open the valve and it becomes almost floppy."
Dion is "a pretty thin lady," Lin said. "She is the kind of typical person who has these kind of symptoms."
Other risk factors for Patulous eustachian tube include pregnancy, fatigue, stress, exercise and temporomandibular joint syndrome in the jaw. Some cases have been linked to medications such as oral contraceptives or diuretics (water pills) that increase urine secretion. Stroke, multiple sclerosis and motor neuron disease also have been implicated.
Symptoms include "distorted autophony" -- hearing one's own voice or breathing, an echoing effect that can interfere with speech -- as well as sensations of wave-like sounds that interfere with auditory perception and a feeling of fullness in the ear. In severe cases, vertigo and hearing loss may occur.
Lin said there is no standard treatment for the disorder, but some people are able to temporarily alleviate symptoms with positional manoeuvres, such as lying down or lowering their head between their knees.
"But obviously you can't walk around all day with your head down."
Patients may also be advised to avoid diuretics and to increase body weight. Certain nasal medications may help to reduce symptoms in some patients, while surgical treatment may be recommended for others.
One of those surgical options involves injecting fat around the eustachian tube to "bulk it up a little bit" to try to make the valve behave as it should, said Lin. "But it's a short-term solution most of the time because the fat is resorbed."
Some people take the extreme step of scarring the valve so it closes, but that can cause fluid to build up or the ear drum to get sucked in, he said.
"With my patients, I tell them there is no easy fix for this ... these patients are very, very challenging because the number one thing is to manage their expectations so they know that what we're going to try may only be temporary or may not work at all."
