What is a eustachian tube?
The eustachian tube is a narrow tube connecting the middle part of the ear to the nasopharynx (the upper part of the throat behind the nose) (1).
What does the eustachian tube do (2)?
- Protecting the middle ear from pathogens such as bacteria, viruses and various other things from the back of the nose and mouth and protecting the ear from hearing sounds caused by your body.
- Clearance of the middle ear space. It is lined by cilia (small hair-like projections) that help with the drainage of mucus secretions from the middle ear to the back of the nose.
- Pressure regulation. When we yawn, chew or swallow, the contraction of muscle that is connected to the eustachian tube causes the tube to open and allows a small amount of air to enter. This results in equalization of the pressure within the middle ear and the ambient pressure. This explains a “popping” sound in the ear heard when there is a rapid increase of outside pressure such as during rapid descent of airplane or underwater diving.
Who gets Eustachian tube dysfunction?
Eustachian tube dysfunction occurs when the eustachian tube is unable to adequately perform the functions above. However, the exact mechanism is still not fully understood (3).
Eustachian tube disorders can be divided into 3 main types (4, 5):
The first type is called “patulous eustachian tube dysfunction (chronic patency)”. This type of dysfunction occurs when the eustachian tube remains open because of the malfunctioned valves. This can result in autophony, a condition described as increased ability to hear own voices, own breathing sounds, or sounds of other bodily functions such as the sound of the heart beating more loudly than usual. Sensation of ear fullness (blocked ear) and clicking and popping in the ears may occur as well. Impaired closure of valve also allows reflux of content from the back of the nose such as pathogens such as bacteria or viruses and acid from the stomach to enter the middle ear (4, 5).
The second type is called “obstructive Eustachian tube dysfunction”. Obstruction of the eustachian tubes often occurs from inflammation of the tube lining secondary to irritations or infections (6). With inflammation, the tube lining becomes swollen resulting in narrower tube. This makes pressure regulation and clearance of mucus secretion more difficult (6). Symptoms of upper respiratory tract infection such as cough, cold, and runny nose or exposure to allergens or chemicals such as smokes may preceding this type of eustachian tube dysfunction (6). Symptoms include hearing impairment or sensation of ear fullness due to failure to equalize pressure between inside the ear and the outside environment. Inability to effectively clear mucus secretions from the middle ear also increases the risk of ear infection (7, 8). Other causes of obstructive eustachian tube dysfunction are enlargement of adenoid, tumour, trauma, anatomical abnormalities (such as nasal septum deviation), and malfunction of the muscles involving in tube opening (9).
The third type is called “baro-challenge-induced eustachian tube dysfunction”. It occurs when the eustachian tube is unable to open adequately with changes of environmental pressure resulting in failure to keep the middle ear pressure equalized with pressure outside (4, 5). Symptoms include ear fullness, popping, ear discomfort, or ear pain with alteration of surrounding pressure such as when on airplanes or when SCUBA diving. The symptoms are typically resolved when returning to the ground level (4). Ear examination and hearing tests are often normal because this type of dysfunction is situation-specific and only occurs when there are changes in atmospheric pressure (4).
Who gets Eustachian tube dysfunction?
Eustachian tube dysfunction occurs in about 1% of the adult populations and 40% of the children populations (10). Young children (mainly those at the age of 1-6 years old) are at higher risk of developing eustachian tube dysfunction because their eustachian tubes are narrower resulting in difficulty for fluid to drain and predisposing to blockages (11). Also, young children at school age are more prone to upper respiratory tract infection which is one of the risk factors for the condition (11).
What are the causes?
Factors predisposing to inflammation
- Upper respiratory tract infections such as common cold, the flu, and sinus infection
- Allergies such as allergic rhinitis
- Irritants such as cigarettes smokes, pollutions, wood fires (they can damage the cilia)
- Gastroesophageal reflux
- Anatomical abnormalities
- Tumours or masses in nose or throat regions
- Enlarged adenoid gland
- Obesity (due to excess fatty deposit along the eustachian tube reducing its diameter)
Changes in altitude such as hiking, flying on an airplane, or going up and down an elevator can trigger symptoms of eustachian tube dysfunction.
If the eustachian tube is not functioning properly, symptoms such as muffled hearing or hearing loss, otalgia (ear pain), tinnitus (ringing in the ears), feeling of fullness in the ear, problems with balance, or autophony (increased ability to hear sound caused by body e.g., your voice, heart beating) may occur (4).
How is it diagnosed?
Ear examination using an otoscope by general practitioner (GP) and a tympanometry to test the middle ear are the initial investigations for those with suggestive symptoms of eustachian tube dysfunction. In brief, tympanometry tests mobility of the eardrums and assess health, function and pressure of the middle ear .
If the initial conservative managements does not work, the GP may make a referral to an ear nose throat specialist for further assessment and discussion for more intensive managements including surgical intervention.
What are the potential complications?
Long-term eustachian tube dysfunction has been associated with damage to the middle ear and the eardrum causing otitis media with effusion (glue ear), middle ear atelectasis (retraction of the eardrum), and chronic otitis media (chronic inflammation of the middle ear) (3).
What are the treatment options?
Management of nasal allergies can reduce the risk of middle inflammation and prevent swelling of the eustachian tube lining. Some of the strategies are listed below:
- Identifying and avoiding the things that trigger allergic symptoms.
- Use of medications such as topical nasal decongestants, antihistamines, and topical steroids to help clear the nose may help relieve symptoms if you have eustachian dysfunction related to nasal allergies (12, 13).
- Self-inflation of the ears may help relieve the symptoms of ear fullness. It can be done by simple measures such as yawning, chewing gum, swallowing, pinching the and blow air out forcibly with your mouth shut to pop the ear or blowing up the balloons to create enough pressure to push air up the eustachian tube (14).
Surgical management is usually indicated when the medical management fails to treat the condition. The common surgical options are tympanostomy (making tiny insertion on the eardrum with or without the insertion of a small tube [also known as grommet] through to help to neutralize pressure between the atmosphere and within the middle ear), eustachian tube tuboplasty (procedure to reduce the thickness of eustachian tube lining to facilitate the tube’s ability to drain and ventilate), and balloon dilation of the Eustachian tube (1, 15).
Can you prevent Eustachian tube dysfunction?
Treating underlying causes and risk factors outlining above such as optimizing management of allergies and keeping well away from respiratory tract infections can help prevent eustachian tube dysfunction (2).
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Author + Affiliation:
Date of Publication +/- Review:
Dr Sheuh Lim