Patulous Eustachian Tube

Patulous Eustachian tube (PET) is a condition in which the Eustachian tube remains abnormally open at rest. Sound and pressure pass directly between the nasopharynx and the middle ear. The patient hears their own breathing and voice (autophony) and has aural fullness.

Incidence is about 0.3 to 6.6 percent of otology patients. It is more common in women (about 2:1) in middle age, and in thin individuals. Symptoms are often intermittent and positional.

The tube normally is closed at rest and opens on swallowing, yawning and sneezing. Closure depends on the mucosal and submucosal tissue (the Ostmann fat pad and venous plexus), the tensor veli palatini and levator veli palatini muscles, and the elasticity of the cartilage.

Causes:

• Significant weight loss, the most common precipitant, from loss of peritubal fat (e.g., dieting, illness, chemotherapy, anorexia nervosa).
• Pregnancy (oestrogen related, with oedema effects).
• Oral contraceptives and oestrogen therapy.
• Dehydration and strenuous exercise.
• Radiotherapy of the head and neck.
• Neurological disease with muscle atrophy (stroke, motor neuron disease, multiple sclerosis, myasthenia gravis).
• Temporomandibular joint disorder, chronic nasal obstruction, mucosal atrophy, and trauma.
• Idiopathic (in many).

• Autophony (hearing own voice loudly and resonantly, as in a "barrel").
• Hearing own breath sounds (the "wind in a tunnel" or "blowing" noise synchronised with respiration).
• Sensation of aural fullness or blocked ear that mimics Eustachian tube obstruction.
• Symptoms are worse when upright, after exercise, and with dehydration or stress.
• Symptoms improve when supine, with the head down (lying down or putting the head between the knees; venous engorgement closes the tube), with nasal congestion, or during upper respiratory tract infection.
• Symptoms also improve when sniffing (sniffing closes the tube by pulling it shut) and by yawning.
• Mild hearing loss in the affected ear is occasionally reported, along with tinnitus (pulse synchronous or respiratory), and tympanic membrane movement synchronous with respiration.
• Bilateral in about 30 percent; psychological distress, anxiety, and avoidance of social interaction with severe symptoms.
• Examination: tympanic membrane retracting and moving outward with breathing, with a normal appearance otherwise.
• The movement is visible on otoscopy, especially with the nostril pinched during forced nasal breathing, or with the patient breathing through the nose with the opposite nostril closed.

• Clinical diagnosis: typical symptoms together with respiratory movement of the tympanic membrane on otoscopy (or by pneumatic otoscopy or microscopy).
• Tympanometry: a respiratory pattern on a prolonged tracing (a wavering baseline in time with breathing), best seen with the patient breathing through one nostril with the other occluded.
• Other tests: sonotubometry (a tone is introduced into the nostril, and detected in the ear canal), tubomanometry, and the Eustachian tube function test.
• Nasopharyngoscopy: a gaping Eustachian tube orifice, and examination to exclude nasopharyngeal mass.
• Imaging (CT of the temporal bone and skull base) to exclude superior semicircular canal dehiscence (which also causes autophony, with a bone conduction hearing above normal), and other causes.
• Audiometry is normal or shows low frequency conduction changes. Vestibular evoked myogenic potentials differentiate from canal dehiscence.
• Exclude other causes: Eustachian tube dysfunction, superior canal dehiscence, hypermobility of the temporomandibular joint, glomus tumours, and palatal myoclonus.
• Assess weight, medication, hormone use, and neurological status.

Many cases are self-limited, particularly with pregnancy or weight regain.

• Reassurance and conservative measures: explain that the condition is benign. Advise hydration, avoiding dehydration and diuretics, caffeine reduction, avoiding strenuous exercise during symptoms, weight gain where relevant, stopping or modifying oestrogen therapy where feasible, and lying down or placing the head down for relief. Treat nasal allergy or congestion.
• Topical therapies to thicken or irritate the Eustachian tube mucosa (to reduce patency):
  • Intranasal normal saline drops or sprays.
  • Nasal drops of a saturated solution of potassium iodide (SSKI, 1 to 3 drops twice daily, or 0.3 to 0.5 mL applied to the tube orifice via a small catheter).
  • Intranasal oestrogen and boric acid salicylic acid powder insufflation.
  • Acid based preparations (powder of boric acid with salicylic acid applied to the pharyngeal orifice) to induce mucosal oedema.
• Topical therapy gives temporary relief and needs frequent reapplication. Its use is limited by irritation and unproven benefit.
• Nasal spray with ephedrine or pseudoephedrine has a variable effect (not recommended). Diazepam and other medications have been tried.
• Procedural options for persistent, disabling symptoms (those who failed conservative therapy):
  • Tympanostomy tube insertion (ventilation tube) provides relief in about 50 percent of patients for symptoms of autophony and aural fullness (by equalising pressures). It may not stop the breathing noise or the hearing of own voice and can carry risks of otorrhoea.
  • Injection of the Eustachian tube orifice (torus tubarius) with bulking agents (hyaluronic acid filler, carboxymethylcellulose, calcium hydroxylapatite, Teflon paste or fat) via an endoscope under local or general anaesthesia. Success is about 60 to 70 percent but frequently temporary (weeks to months), and repeat treatments are needed.
  • Surgical options: shim (cartilage graft or silicone shim) insertion into the Eustachian tube lumen via transtympanic or transnasal access.
  • Ligation, cauterisation or plugging (using a cartilage plug, fat plug, or temporalis muscle) of the tube lumen in the middle ear or the pharyngeal orifice, closing the tube, with success of about 70 to 90 percent in most series.
  • The tensor veli palatini muscle can be plicated or an adjacent tube lumen reconstructed. Transcatheter insertion of tube plugs is also used.
  • Complications: middle ear effusion (conductive hearing loss), otitis media, tympanic membrane retraction, and extrusion.
• Treat the underlying causes: treat dehydration, malnutrition, and neurological disorders. The symptoms in pregnancy usually resolve after delivery.
• Psychological support, and exclusion of anxiety, as chronic autophony can cause marked distress.
• Prognosis: variable; 40 to 60 percent improve spontaneously with weight gain, hydration or time, while some have chronic symptoms and fluctuations.