The Eustachian tube: Function and dysfunction

October 2002

A dysfunctional and/or immature Eustachian tube is believed to be the cause of most cases of otitis media with effusion (OME). The purpose of this article is to present some information on Eustachian tube function and dysfunction.

Anatomy and physiology

The adult Eustachian tube is a conduit from the anterior superior part of the middle ear to the open cavity of the nasopharynx. The tube has an elongated hourglass shape with a constricted area known as the isthmus located near the junction of the osseous and pharyngeal zones. From the middle ear, the first third of the tube (osseous) is encased in bone and the distal two-thirds (pharyngeal) in cartilage. The pharyngeal two-thirds of the Eustachian tube is closed at rest and opens during swallowing, sneezing or performance of a valsalva maneuver. At the nasopharyngeal end, a ring of lymphoid tissue known as the tubal tonsil of Gerlach surrounds the orifice.

The Eustachian tube in infancy differs anatomically and physiologically from that of the adolescent. In infancy, the Eustachian tube is shorter (18 mm) and has a more acute angle (10°) compared with the length (36 mm) and angle (45°) during adolescence and adulthood.

The shorter tube during infancy and early childhood facilitates reflux of bacteria-laden secretions from the nasopharynx. In addition, the isthmus (constricted zone) is not angulated in infants as it is in adolescents and adults. This reduces the protective function of the Eustachian tube. Infants also are less able to actively open the Eustachian tube that accounts in part for their susceptibility to middle-ear disease.

The Eustachian tube has three primary functions: 1) ventilation of the middle ear so that ambient pressure and middle ear pressure are similar; 2) protection of the middle ear from reflux of nasopharyngeal secretions and bacterial flora; and 3) drainage of secretions from the middle ear into the nasopharynx.

Optimum function of the Eustachian tube depends on a number of factors, including its length and angulation with the horizontal plane, the function and angulation of the tensor veli palatini muscle that opens up the pharyngeal end of the tube (levator palatini assumes a role in late childhood), the amount of surfactant produced by the pharyngeal zone, and the viscosity of liquid in the middle ear.

The consequences of Eustachian tube dysfunction decrease with age. Dysfunction of the Eustachian tube can occur from anatomical causes, such as lymphoid tissue, edema, inflammation, and viscosity and amount of mucoid effusion or physiological causes, such as barotrauma, middle ear atelectesis, deficiency of surfactant production, ciliary dysfunction and abnormal patency of the pharyngeal tubal orifice.

In the meantime, it may be necessary to reestablish Eustachian tube patency. Here are some techniques I use and situations where they would be appropriate.

Politzer technique

The Politzer technique is a simple method of introducing positive pressure into one nostril with the goal of aeration of the middle ear via the Eustachian tube. A 30 cc rubber bulb with a conical shaped plastic tip can be purchased inexpensively (infant nasal aspirator, many dollar stores or most pharmacies). Secretions are removed from both nasal passages by suction or by simply having the older child blow his nose. It may be necessary to instill one or two sprays of phenylephrine 0.125% or 0.25% into each nostril to reduce edema of the nasal mucosa.

The cooperative child is given a sip of water and instructed to hold the water in the mouth until the doctor shouts “swallow.” The conical tip of the bulb syringe is seated firmly into one nostril while the index finger of the opposite hand occludes the other nostril. On the physician’s command “swallow,” the child swallows the water in his/her mouth. Synchronous with the child’s deglutition, the physician gently compresses the rubber bulb permitting a bolus of compressed air to enter the nose and nasopharynx. The act of deglutition activates the tensor veli palatini muscle that opens up the Eustachian tube orifice. The bolus of air further distends the Eustachian tube and the air bolus is forced into the middle ear cleft neutralizes any negative pressure and ventilating the middle ear. For chronic problems of Eustachian tube dysfunction, the accompanying parent is told to purchase an infant nasal syringe for home use.

The Otovent

The Otovent is a balloon that fits over a flanged end of a similar conical plastic nasal occluder. The balloon is inflated by the child blowing air out of his nose into plastic nasal occluder to which the balloon is attached. When it is fully expended, the balloon neck is pinched off and the nasal occluder is inserted into one nostril. The child is instructed to swallow as the balloon is deflated into the nasal cavity. A portion of the bolus of air from the balloon enters the Eustachian tube and ventilates the middle ear, similar to the Politzer technique.

Problems and solutions

Problem 1: Otalgia secondary to negative middle ear pressure from rhinitis-induced ventilation dysfunction of Eustachian tube. Chief complaint is earache. Otoscopic examination shows a translucent tympanic membrane with the malleus handle not at the normal 12 o’clock position, but at a 2:30 or 3:00 position. Application of negative pressure or suction through the pneumatic otoscope reveals brisk movement outward toward the examiner and no movement inward toward the middle ear.

Solution 1: Providing positive pressure directly into the nose by Politzer technique or by use of the Otovent. Or, use of valsalva maneuver or blowing up new balloons to transmit positive intraoral pressure into the middle ear via the Eustachian tube.

Problem 2: Child has a past history of severe Eustachian tube ventilation dysfunction on descent of aircraft and the child is scheduled to travel by plane.

Solution 2: Make sure that nose is clear of secretions before descent of aircraft. If necessary, instill oxymetrazolone (Afrin, Schering-Plough) nasal spray (0.125% or 0.25%) nasal drops or spray to reduce edema of nasal passages. Use same solution as problem 1.

Problem 3: Complaints of fullness in ear and autophonia caused by dysfunction of middle ear ventilation of the Eustachian tube during allergy season.

Solution 3: Treat for seasonal rhinitis with steroid nasal spray with or without non-sedating antihistamine. May add solution to problem 1 if not improved within a few days.

Problem 4: Subacute (two to six week duration) or chronic serous (thin serum-colored liquid) middle ear effusion.

Solution 4: OtoventTM or Politzer technique in office and daily at home.

Problem 5: Chronic (greater than three-month duration) unilateral or bilateral mucoid thick middle ear effusion.

Solution 5: Short course of methylprednisolone or prednisone (1 mg/kg/day) for seven to 10 consecutive days. One of us also prescribes an antibiotic, such as twice-daily course of amoxicillin-clavulanate (Augmentin, GlaxoSmithKline) as a safety net because pathogenic bacteria can sometimes be recovered from mucoid effusions. On re-evaluation visit day 10-12, the viscosity of remaining mucoid middle-ear effusion may be reduced enough to institute effective drainage by use of the Otovent or the Politzer technique. Note that this approach is not supported by evidence-based medicine.

For more information:

• Bunne M, Magnuson B, Falk B, et al. Eustachian tube function varies over time in children with secretory otitis media. Acta Otolaryngol. 2000;120(6):716-723.
• Chan KH, Bluestone CD. Lack of efficacy of middle-ear inflation: treatment of otitis media with effusion in children. Otolaryngol Head Neck Surg. 1989;100(4):317-323.
• Chan KH, Cantekin EI, Kamavas WJ, et al. Autoinflation of eustachian tube in young children. Laryngoscope. 1987;97(6):668-674.
• Silverstein M. Can I fly Doc? Eustachian tube dysfunction. Aust Fam Physician. 2000;29(1):55-56.
• Silman S, Arick D. Efficacy of a modified politzer apparatus in management of eustachian tube dysfunction in adults. J Am Acad Audiol. 1999;10(9):496-501.