Eustachian Tube Dysfunction

Definition and epidemiology

The Eustachian tube connects the middle ear with the nasopharynx. It is normally closed and opens briefly during swallowing and yawning to equalise middle ear pressure with the surroundings, clear secretions from the middle ear and protect it from nasopharyngeal sound. An international consensus statement defines Eustachian tube dysfunction as a set of symptoms and signs suggesting a failure of middle ear pressure regulation. Symptoms lasting less than three months indicate acute dysfunction and those lasting longer indicate chronic dysfunction. Otitis media is a separate diagnosis and is not labelled as Eustachian tube dysfunction (Schilder et al., 2015).

The consensus describes three types (Schilder et al., 2015). In obstructive (dilatory) dysfunction the tube fails to open adequately. This type is subdivided into functional obstruction caused by mucosal swelling, dynamic dysfunction in which the muscles that open the tube fail, and anatomical obstruction caused by a mass or similar lesion. In baro-challenge-induced dysfunction the tube works under everyday conditions but cannot cope with rapid pressure changes such as flying or diving. The third type, the patulous Eustachian tube, stays open more than it should and is covered separately in Patulous Eustachian Tube.

A US national study that defined the condition by tympanometry alone estimated the prevalence of Eustachian tube dysfunction in adults at 4.6%, about 11 million people. Prevalence rose with age, reaching 8.3% at 65 years and over; the authors note that this approach probably underestimates the true figure (Shan et al., 2019). In children the tube is shorter and more horizontal, so dysfunction is common and is the main factor behind otitis media with effusion.

Symptoms and signs

Symptoms common to all types reflect pressure imbalance: fullness, blockage or an underwater feeling, crackling and popping, discomfort or pain, muffled hearing and tinnitus. Some patients notice their own voice sounding loud (autophony). The obstructive type often starts after an upper respiratory tract infection or a flare of allergic rhinitis, and patients frequently perform Valsalva manoeuvres or move their jaw to clear their ears (Schilder et al., 2015).

In baro-challenge-induced dysfunction, symptoms appear only when ambient pressure changes, particularly during an aircraft’s descent or when diving deeper, and usually resolve at ground level. A large pressure change can cause fluid or blood to collect in the middle ear, turning the picture into ear barotrauma (Schilder et al., 2015).

On otoscopy the eardrum may look retracted in the obstructive type, with a prominent handle of malleus; a fluid level or air bubbles may be visible. In the baro-challenge-induced type, examination and tympanometry are usually normal when there is no pressure change. Long-standing dysfunction can lead to permanent retraction pockets and adhesive otitis.

Causes and risk factors

The commonest causes of functional obstruction are upper respiratory tract infections, allergic and non-allergic rhinitis, chronic rhinosinusitis and exposure to tobacco smoke, all of which make the tubal mucosa swell and opening more difficult. Gastro-oesophageal reflux has also been proposed as a contributor. In children, large adenoids, cleft palate and craniofacial conditions such as Down syndrome are important risk factors. In dynamic dysfunction, poor action of the tensor veli palatini muscle, which opens the tube, is responsible.

Anatomical obstruction is less common: a nasopharyngeal mass or tumour, or scarring after skull base radiotherapy or surgery, can narrow the tube. Unexplained, unilateral, persistent dysfunction or effusion in an adult therefore always calls for examination of the nasopharynx (Schilder et al., 2015). In the baro-challenge-induced type, the main problem is that the tube cannot open quickly enough during rapid pressure changes, sometimes with mild mucosal swelling.

Audiological and clinical assessment

The diagnosis rests on history and examination; there is no universally accepted single test of tubal function. According to the consensus statement, a diagnosis of obstructive dysfunction requires symptoms together with eardrum retraction on otoscopy or negative middle ear pressure on tympanometry. Baro-challenge-induced dysfunction is usually diagnosed on history alone. Checking whether the ear clears with a Valsalva or Toynbee manoeuvre is not sensitive or specific enough to be useful (Schilder et al., 2015).

• Tympanometry: the obstructive type typically gives a type C tympanogram with peak pressure shifted to negative values; if fluid has collected, the trace flattens (type B with normal ear canal volume). In the baro-challenge-induced type the tympanogram is usually normal between episodes (type A). In the patulous type, fluctuations in time with breathing may be seen.
• Pure-tone audiometry: hearing may be normal, or there may be a mild conductive loss, mainly at low frequencies. Bone conduction is normal; any sensorineural component calls for a search for other causes.
• Acoustic reflexes: may be absent with marked negative pressure or effusion; they should be measured at the tympanometric peak pressure.
• ETDQ-7 questionnaire: the only patient-reported measure to have undergone validation (Schilder et al., 2015). It has seven items, each scored from 1 to 7, and in the original study a total score above 14.5 was taken as consistent with dysfunction (McCoul et al., 2012). In the Turkish adaptation, internal consistency (Cronbach’s alpha) was 0.714, and no healthy control scored above this threshold (Özgür et al., 2018).
• Eustachian tube function tests: tubomanometry, the nine-step inflation-deflation test and sonotubometry are used in research and specialist centres; there are no standardised diagnostic criteria yet.
• Nasopharyngoscopy and imaging: endoscopy may reveal an underlying cause. Imaging is not routine and is reserved for suspected additional pathology (Schilder et al., 2015).

The differential diagnosis includes other causes of aural fullness: earwax impaction, otitis media with effusion, patulous Eustachian tube, Ménière’s disease and sudden sensorineural hearing loss, superior semicircular canal dehiscence and temporomandibular joint problems. Measuring bone conduction thresholds is important so that inner ear causes of fullness are not missed.

Treatment and audiological rehabilitation

Acute dysfunction often resolves as an upper respiratory infection clears, and watchful waiting may be enough. Treating underlying nasal problems (allergic rhinitis, rhinosinusitis), stopping smoking and self-inflation (autoinflation) exercises are commonly advised; the use of nasal sprays or other medicines is decided by the doctor. A 2014 systematic review of interventions for adult Eustachian tube dysfunction concluded that the evidence at that time was insufficient to draw conclusions about the effectiveness of any intervention (Llewellyn et al., 2014).

Balloon dilation widens the tube by inflating a balloon placed through the nose into its cartilaginous part. Two randomised controlled trials form the core of the evidence. In a 60-patient trial, ETDQ-7 scores at six weeks fell by a mean of 2.9 points with balloon dilation and 0.6 points with medical management alone, and the benefit persisted to 12 months (Meyer et al., 2018). In a 323-patient trial, the tympanogram had normalised at six weeks in 51.8% after balloon dilation and in 13.9% of controls (Poe et al., 2018). In the UK, the National Institute for Health and Care Excellence (NICE) judged the evidence adequate to support the procedure with standard arrangements for clinical governance, consent and audit; the committee also noted that there was little evidence on the benefit of repeat procedures (NICE, 2019).

Persistent negative pressure, effusion or progressive retraction may be treated with a ventilation tube (grommet), which ventilates the middle ear independently of the tube but does not treat the underlying dysfunction and may extrude spontaneously. Grommets are also used selectively for frequent flyers or divers with baro-challenge-induced dysfunction; the decision rests with the surgeon. During follow-up the audiologist repeats tympanometry and audiometry to document change, and completing the ETDQ-7 before and after treatment gives an objective measure of benefit. Hearing aids are rarely needed.

Impact on quality of life and advice

Persistent fullness and muffled hearing can make meetings and phone calls harder, and constantly trying to clear the ears is tiring. Baro-challenge-induced dysfunction can make flying and diving painful, which matters for people who fly or dive for work. Knowing that the symptoms are not dangerous and understanding the follow-up plan helps to reduce anxiety.

When flying, swallow often, chew gum or sip water, especially once the descent begins; staying awake makes it easier to clear your ears. Babies can be fed from the breast or a bottle during descent. Avoid flying and diving with a blocked nose or a cold where possible, and ask your doctor if it cannot be avoided. When diving, equalise early and often from the surface and do not descend further if you feel pressure. Do not blow your nose forcefully; close one nostril and clear the other gently. Stopping smoking reduces mucosal swelling. Ask for reassessment if symptoms last more than three months or persist in one ear.