At a glance......
- 1 Causes of Eustachian Tube Dysfunction
- 2 Symptoms of Eustachian Tube Dysfunction
- 3 Diagnosis of Eustachian Tube Dysfunction
- 4 Treatment of Eustachian Tube Dysfunction
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Eustachian tube dysfunction (ETD) is the inability of the Eustachian tube to adequately perform these functions. However, the precise function and mechanisms of the Eustachian tube and the underlying causes of dysfunction are complex and not fully understood.[rx] From a diagnostic perspective, ETD is also poorly defined.
Eustachian tube dysfunction may occur when the mucosal lining of the tube is swollen, or does not open or close properly.[rx] If the tube is dysfunctional, symptoms such as muffled hearing, pain, tinnitus, reduced hearing, a feeling of fullness in the ear or problems with balance may occur. Long-term ETD has been associated with damage to the middle ear and the eardrum.[rx] Complications include otitis media with effusion (glue ear), middle ear atelectasis (retraction of the eardrum), and chronic otitis media.[rx,rx] However, the role of the Eustachian tube in the development of other middle ear conditions is not fully understood.1 Middle ear ventilation is increasingly seen as being associated with other mechanisms, such as those relating to gaseous exchange through the middle ear mucosa.[rx,rx] Therefore, it may be that problems with middle ear ventilation (and therefore symptoms and signs previously attributed to ETD) may not all be associated with problems with or dysfunction of the Eustachian tube. Abnormal patency (patulous Eustachian tube) is a separate condition, in which the Eustachian tube remains intermittently open, causing an echoing sound of the person’s own heartbeat, breathing, and speech.
Causes of Eustachian Tube Dysfunction
The lining of the Eustachian tube can become swollen and the Eustachian tube can become dysfunctional following the onset of an infectious or inflammatory condition such as an upper respiratory tract infection, allergic rhinitis or rhinosinusitis, leading to difficulties in pressure equalization, discomfort and other symptoms.[rx,rx] Nasal septal deviation has also been associated with symptoms of ETD; this is based on some studies which suggested that, in patients who were unable to equalize pressure during scuba training or submarine service, submucous resection of the nasal septum resolved apparent ETD symptoms.[rx–rx] Dysfunction of the Eustachian tube may also be related to failure of the muscles associated with Eustachian tube opening.[rx] Extrinsic compression of the Eustachian tube potentially due to inflammation or enlargement of the adenoids, tumour or trauma may also result in ETD,[rx,rx] although these conditions and their management are beyond the scope of this review. The incidence of ETD is disproportionately high in patients with cleft palate who may be considered a discrete clinical population.[rx] Other potential risk factors include tobacco smoke, reflux and radiation exposure.[rx–rx] There appears to be no association with sex,[rx] although it has been suggested that ethnicity and geographical factors (such as proximity to the poles) are associated with increased incidence and prevalence.[rx]
There are limited data on ETD prevalence and incidence, which may reflect the lack of consensus regarding how ETD is defined. A UK national study of hearing[rx] reported that 0.9% of the 2708 adults assessed (from an initial sampling of 48,313) were considered to have ETD, based on otoscopic examination and audiological assessment. However, this may be an underestimate; a recent study stated that most otolaryngologists encounter a much higher incidence of the condition in their practices.[rx]
ETD happens if the Eustachian tube becomes blocked, if the lining of the tube swells, or if the tube does not open fully to allow air to travel to the middle ear.
Common colds and other nasal, sinus, ear or throat infections
- By far the most common cause of ETD is the common cold (upper respiratory tract infection).
- The blocked nose or thick mucus that develops during a cold or other infection, may block the Eustachian tube.
- An infection may also cause the lining of the Eustachian tube to become inflamed and swollen.
- Most people have had a cold when they haven’t been able to hear so well – this is due to ETD.
- Symptoms may last for a week or so (sometimes longer) after the other symptoms of the infection have gone. This is because the trapped mucus and swelling can take a while to clear even when the germ causing the infection has gone.
- Sometimes the infection that sets it off is very mild but even so, in some people, ETD can still develop.
- Glue ear is a condition where the middle ear fills with glue-like liquid.
- It is a common condition in children.
- The Eustachian tube becomes congested and prevents the free flow of air into the middle ear, causing the difference in air pressure mentioned above. The eardrum becomes tight, reducing its ability to vibrate. This results in dulled hearing. The situation is made worse by the glue-like fluid damping down the vibrations of the drum even further.
- It clears by itself in most cases but some children need an operation to solve the problem.
Allergies that affect the nose, such as persistent rhinitis and hay fever, can cause extra mucus and inflammation in and around the Eustachian tube and lead to having symptoms for several months.
- Smoking can stop the tiny hairs that line the Eustachian tube from working.
- Smoking can also cause tissues at the back of the nose and throat (including the adenoids) to enlarge, blocking the Eustachian tube.
- If you smoke and are having problems with long-term (chronic) ETD you should try to stop smoking.
- Anything that causes a blockage to the Eustachian tube can cause muffled hearing – for example, enlarged adenoids in children.
- Rarely, a tumor behind the eardrum or at the back of the nose (the nasopharynx) can mimic the symptoms of ETD. These types of tumors are very uncommon and usually cause other symptoms in addition to ETD, such as headache, a hoarse voice, and a constantly blocked nose.
What causes long-term Eustachian tube dysfunction?
For most people who experience ETD, it settles by itself within a couple of weeks. But in some people, it seems to go on for a long time – many months. It is not known why some people are more prone to this happening than others.
Some common causes of long-term (chronic) ETD:
- Chronic sinusitis – up to half of people with chronic ETD.
- Persistent rhinitis.
- Smoking-related changes to the nose and throat.
In around 1 in 5 people who have long-term ETD, no cause is found. There is no evidence that there is a genetic cause and it doesn’t appear to run in families.
Symptoms of Eustachian Tube Dysfunction
Symptoms of ETD may include:
- fullness in the ears
- feeling like your ears are “plugged”
- changes to your hearing
- ringing in the ear, also known as tinnitus
- clicking or popping sounds
- ticklish feelings in the ears
Other symptoms that may also develop
- Due to the eardrum being tense and stretched.
- Pain may come and go.
- Rarely causes constant ear pain. If your ear is hurting all the time, it may be due to a different cause and you should see a doctor.
- Ringing or buzzing in the ear (tinnitus):
- This is as well as muffled hearing.
- ETD doesn’t cause tinnitus on its own.
- Mild dizziness (vertigo) may occur.
Diagnosis of Eustachian Tube Dysfunction
There are no comprehensive guidelines on diagnosis of ETD.[rx] Diagnosis is generally based on medical history and clinical examination to identify potential underlying causes.[rx] The UK national survey defined ETD as the presence of a normal or abnormal but intact tympanic membrane with a middle ear pressure of < –100 mmH2O and an air–bone gap of ≥ 15 decibels (dB).[rx] The criteria were used for a presumptive diagnosis of ETD. The authors noted that it was a relatively non-specific category, which may include patients in the early or late stages of an episode of otitis media with effusion. However, the presence of either of these signs is not usually considered to be either necessary or sufficient for the diagnosis of ETD in clinical practice; while negative middle ear pressure often indicates ETD, patients with ETD may have normal middle ear pressure and those with negative middle ear pressure may be asymptomatic. Moreover, while an intact eardrum was a requirement of the survey criteria, several investigators include patients with perforated eardrums.
Although not used in the survey, symptoms of dysfunction are usually a necessary condition for diagnosis in clinical practice. Common diagnostic factors include the inability to ‘clear’ or ‘pop’ the ear with changes in barometric pressure, together with other patient-reported symptoms (e.g. aural fullness, pain, muffled hearing).[rx] There are a number of tests that are used to inform diagnosis: otoscopy, tympanometry, and nasal endoscopy are initial options in a secondary care setting. Evidence on the predictive value of Eustachian tube function tests is limited, and several tests may be needed for a more reliable and comprehensive assessment of the Eustachian tube function.[rx] Currently, there is no commonly used patient-reported outcome measure. A scale for the assessment of ETD [the 7-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7)] was tested for validity; this is a questionnaire addressing a range of symptoms associated with ETD, which is completed by the patient. The data available on reliability were based on a relatively small number of patients (n = 50) and controls (n = 25), but the test discriminated patients and controls and exhibited good test-retest reliability.[rx] However, this represents a recent development and it is not yet widely used. Another relevant scale which is also completed by patients, the 22-item Sinonasal Outcome Test (SNOT-22), has been used to assess symptoms of the related condition of rhinosinusitis.[rx]
The lack of clearly defined diagnostic criteria, together with the uncertainty relating to the etiology of ETD, presents a key challenge in undertaking a review of interventions for its treatment. Lack of consensus on the necessary features for diagnosis, including clinical history, requires additional awareness of the risk of error and bias in the selection of studies, as well as increasing the probability of clinical heterogeneity in the included studies.
Treatment of Eustachian Tube Dysfunction
Although ETD symptoms are common, they are often mild and generally resolve after a few days. Simple actions such as swallowing, yawning, chewing or forced exhalation against a closed mouth and nose can help to equalise pressure in the middle ear and resolve symptoms. However, symptoms sometimes persist, in which case treatment may be desirable. There are a number of non-surgical and surgical treatment options aimed at improving Eustachian tube function, but there is limited consensus about management.
Non-surgical management strategies include:
- Active observation, which involves monitoring the symptoms to determine whether or not they naturally resolve.
- Supportive care, which includes advice about self-management such as to swallow, yawn, or chew to help equalize the pressure in the middle ear.
- Pressure equalization methods, which is a technique whereby the Eustachian tube is reopened by raising the pressure in the nose. This can be achieved in several ways, including forced exhalation against a closed mouth and nose (Valsalva maneuver). Other methods include blowing up a balloon through each nostril, using an anesthetic mask[rx] or the use of mechanical devices.[rx,rx] The aim is to introduce air into the middle ear, via the Eustachian tube, equalizing the pressures and allowing better fluid drainage.
- Nasal douching, in which the nasal cavity is washed with a saline solution to flush out excess mucus and debris from the nose and sinuses.[rx]
- Decongestants, antihistamines, nasal or oral corticosteroids are aimed at reducing nasal congestion and/or inflammation of the lining of the Eustachian tube.
- Antibiotics, for the treatment of rhinosinusitis.
- Simethicone, which is currently being investigated in adults to assess whether or not it can help to break up bubbles that may block the opening of the Eustachian tube in the back of the nose during a cold, allowing air to pass between the nose and middle ear.[rx] This is not currently a management option used in the UK.
We understand that, currently, the main surgical treatment in the UK is a pressure-equalizing tube (also known as tympanostomy tube, ventilation tube, or grommet) which is inserted into the eardrum through a small incision. Pressure equalizing tubes typically extrude after 6–9 months. Long-acting tubes are occasionally used, although these may be prone to crusting, infection, obstruction, and permanent tympanic membrane perforation. This may be performed under either general or local anesthesia. Newer surgical methods which are mainly used in the context of research include:
- Balloon dilatation (dilatation) of the Eustachian tube, a procedure which aims to dilate the Eustachian tube and improve its function. It consists of introducing a balloon catheter into the Eustachian tube through the nose, under transnasal endoscopic vision. The balloon is filled with saline. The pressure is maintained for approximately 2 minutes, following which the balloon is emptied and removed. The procedure has been performed experimentally under local and general anesthesia.
- Transtibial application of fluids, an emerging approach for the application of fluids to the middle ear via the Eustachian tube. The transtibial application approach involves placing a nasal microendoscope within the Eustachian tube under local anesthesia via its nasopharyngeal opening. Subsequently, fluids are applied through an additional working channel after microendoscopic evaluation.[rx]
- Eustachian tuboplasty, an emerging treatment in which a laser or rotary cutting tool is used to strip away enlarged mucous membranes and cartilage to clear obstruction to the Eustachian tube. Tuboplasty has been used in patients with chronic ETD as an alternative to pressure equalizing tubes which may have extruded on numerous occasions.[rx,rx] The intervention has also been used for middle ear atelectasis or serous effusion.[rx]
There is no consensus on indications for treatment, or on the optimal timing of the interventions. Surgical interventions are generally (though not exclusively) used where ETD is resistant to other interventions. A step-up approach is usually adopted, from primary to secondary and tertiary care settings. Treatment choice is based on etiology, severity and persistence of symptoms, as well as the degree of invasiveness of the treatment and surgical preference.