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Eustachian Tube : Anatomy & Disorders

& Secretory Otitis

MediaSreelakshmi M

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Anatomy

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Muscles Related to E.T

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Lining of Eustachian Tube

• Pseudostratified ciliated columnar epithelium interspersed with mucous secreting goblet cells

• Submucosa of cartilagenous part rich in seromucinous gland

• Cilia beat in direction of nasopharynx

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Nerve Supply

• Sensory & parasympathetic : tympanic branch of glossopharyngeal N

• Tensor veli palatini: V3

• Levator veli palatini pharyngeal plexus

• Salpingopharyngeus (cranial part of XI N via vagus)

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Infant ET v/s Adult ETINFANT ADULT

LENGTH 13-18 mm at birth 36 mm

DIRECTION More horizontal Forms an angle of 45° with the horizontal

ANGULATION AT ISTHMUS No angulation Angulation present

BONY VERSUS CARTILAGINOUS PART

Bony part> 1/3 of the total length

Bony part 1/3; cartilaginous part2/3

TUBAL CARTILAGE flaccid Comparatively rigid

DENSITY OF ELASTIN AT THE HINGE

Less dense More dense

OSTMANN’S PAD OF FAT Less in volume Large & helps to keep the tube closed

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Functions

1. Ventilation & regulation of ME pressure

2. Protective funtions– Nasopharyngeal sound pressure– Reflux of nasopharyngeal secretions

3. Clearance of ME secretions

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ET Function Tests

• VALSALVA TEST– Principle: positive pressure in the nasopharynx causes air

to enter the Eustachian tube

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– Tympanic membrane perforation- a hissing sound– Discharge in the middle ear- cracking sound– Only 65% of persons can do this test.– Contraindications:• Atrophic scar of tympanic membrane which can

rupture• Infection of nose & nasopharynx

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• Politzer test– Done in children who are unable to perform valsalva

test.

– Olive shaped tip of the politzer’s bag is introduced into the patient’s nostril on the side of which the tubal function is desired to be tested

– Other nostril closed & the bag compressed while at the same time the patient swallows or says “ik,ik,ik”

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– By means of an auscultation tube a hissing sound is heard.

– Compressed air can also be used instead of politzer’s bag

– Test is also therapeutically used to ventilate the middle ear.

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• Catheterisation

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– Complications:• Injury to Eustachian tube opening • Bleeding from nose• Transmission of nasal & nasopharyngeal infection into

middle ear• Rupture of atrophic area of tympanic membrane

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• Toynbee’s test– Uses negative pressure

• Tympanometry (inflation-deflation test)– +Ve & -ve pressures are created in the external ear

and the patient swallows repeatedly– in patients with perforated or intact tympanic

membrane• Radiological Test• Saccharine/ Methylene blue Test– Saccharine solution– Methylene blue dye– Ear drops into ear with TM perforation

• Sonotubometry

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Disorders of ET

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Tubal Blockage

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mechanical

• intrinsic

• Extrinsicfunct

ional

• Collapsebot

hBlock

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• Symptoms of tubal occlusion– Otalgia– Hearing loss– Popping sensation– Tinnitus– Disturbances of equilibrium

• Signs of tubal occlusion– Retracted TM– Congestion along the handle of malleus and pars tensa– Transudate behind TM

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• Clinical causes of ET obstruction– Upper respiratory tract infection– Allergy– Sinusitis– Nasal polypi– DNS– Hypertrophic adenoids– Nasopharyngeal tumour/ mass– Cleft palate– Submucous cleft palate– Down’s syndrome

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Adenoids• Adenoids cause tubal dysfunction by:– Mechanical obstruction of the tubal opening– Acting as reservoir for pathogenic organisms– Inflammatory mediators in allergy cause tubal

blockage• Adenoids can cause otitis media with effusion or

recurrent acute otitis media• Adenoidectomy

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large adenoid blocking left et

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Cleft palate • Tubal dysfunction due to:– Abnormalities of torus tubaris– Tensor veli palatini doe not insert into the torus

tubaris• Otitis media with effusion is common in these

patients

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Down’s syndrome

• Dysfunction due to:– Poor tone of tensor veli palatini– Abnormal shape of nasopharynx

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Retraction Pockets & ET

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• Any obstruction in the ventilation pathway retraction pockets or atelectasis of tympanic membrane– Obstruction of Eustachian tube total atelectasis of tm

– Obstruction at additus cholesterol granuloma & collection of mucoid discharge in mastoid air cells

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• Other changes – Thin atrophic TM– Cholesteatoma– Ossicular necrosis– Tympanosclerotic changes

• Management– Repair of irreversible pathologic processes– Establishment of ventilation

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Patulous Eustachian Tube• ET is abnormally patent• Causes:– Idiopathic, rapid weight loss, pregnancy (esp 3rd trim)

& multiple sclerosis• Chief complaints– Autophony, hearing his own breath sounds

• Pressure changes in the nasopharynx are easily transmitted to the ME

• Movements of the TM can be seen with inspiration & expiration

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• Management– Acute cases Usually self-limiting– Weight gain & oral administration of KI – Long standing cases = cauterisation/ insertion of grommet

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EXAMINATION OF EUSTACHIAN TUBE

Pharyngeal end of eustachian tube :posterior rhinoscopy, rigid nasal endoscope or flexible nasopharyngoscope

Tympanic end :microscope or endoscope

Simple examination of TM may reveal retraction pockets or fluid in the me

Movements of TM with respiration point to patulous eustachian tube

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• Aetiologic causes of eustachian tube dysfunction assessed through:– Nasal examination– Endoscopy– Tests of allergy– CT scan of temporal bones– MRI to exclude multiple sclerosis

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Otitis Media with Effusion

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Serous otitis mediaSecretory otitis mediaMucoid otitis media“Glue Ear”

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• Insidious condition characterized by accumulation of non purulent effusion in ME cleft

• Effusion is thick & viscid.

• Fluid is sterile

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Pathogenesis

• Malfunctioning of Eustachian tube

• Increased secretory activity of ME mucosa

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Aetiology

1. Malfunctioning of Eustachian tube– Adenoid hyperplasia– Chronic rhinosinusitis– Chronic tonsillitis– Tumors ( to be excluded in unilateral ser. OM in

adults)

2. Allergy3. Unresolved otitis media4. Viral infections

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Clinical Features

Symptoms : affects 5-8 yrs age gpHearing lossDelayed & defective speechMild earaches

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Otoscopic Findings– Dull & opaque TM– Loss of light reflex– TM: yellow grey or bluish– Fluid level & air bubbles may be seen– Restricted mobility of tm– Thin leash of vessels along malleus handle/ periphery

of TM == differentiate from acute supp. Otitis media– TM: varying degree of retraction

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Hearing Tests• Tuning fork test-conductive hearing

loss• Audiometry-conductive hearing loss of

20-40db• Impedance Audiometry-reduced

compliance indicates presence of fluid• X-ray mastoid-clouding of air cells due

to fluid.

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TreatmentMedical

Decongestants

Antihistaminics

Steroids

Antibiotics

Surgical Myringotomy & Aspiration

Grommet Insertion

Tympanotomy/ cortical mastoidectomy( loculated thick fluid/ chol. granuloma)

Surgical treatment of causative factor

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Sequelae of Chronic Secretory Otitis Media

• Atrophic TM & atelectasis of ME• Ossicular necrosis• Tympanosclerosis• Retraction pockets & cholesteatoma• Cholesterol granuloma

50The above picture shows a very thin or atelectatic eardrum (tympanic membrane) which is draped over the promontory and round window nitch.

51Cholesterol granuloma

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