Eustachian Tube Its Disorders otalgia Dr Sharwak Ramlan

Eustachian Tube & Its Disorders otalgia Dr. Sharwak Ramlan

• 16 th century anatomist Eustachius. • pharyngotympanic tube. • Connects the front wall of the middle ear with the nasopharynx. • Develops from 1 st pharyngeal pouch.

Anatomy

Anatomy • Adult: 36 mm – downwards, forwards & medially – Angle of 45˚ with horizontal. • Bony( lat 1/3 rd – 12 mm) & • Fibrocartilaginous (med 2/3 rd – 24 mm) parts. • Their junction – Isthmus. • Ostmann’s pad of fat: laterally to the membranous part

Fibrocartilaginous part • Single piece of cartilage folded on itself. • Whole of medial lamina, roof and part of lateral lamina. • Rest of lateral lamina – fibrous membrane • Elastin hinge: The junction of medial & lateral lamina, at the roof. - rich in elastin fibres – by its Recoil -tube closed.

Tympanic end: • 5× 2 mm – in anterior wall of ME. • Little above floor Pharyngeal end: • Slit - like vertically. • Cartilage - an elevation – Torus Tubaris. • In lateral wall of nasopharynx. • 1 cm behind IT.

Muscles • Tensor veli palatani: medial fibres attached to lat lamina of the tube – help to open the tubal lumen – dialater tube muscle. • Levator veli palatani. • Salpingopharyngeus.

Lining of ET • Pseudostratified ciliated columnar epithilium with mucous secreting goblet cells. • Submucosa – rich in seromucinous glands • Cilia beat in direction of nasopharynx.

Nerve supply • Tympanic branch of CN IX – sensory & parasympathetic secretomotor fibres. • Tensor veli palatani – Mandibular branch of Trigeminal N. • Levator veli palatani & salpingopharyngeus – pharyngeal plexus ( cranial part of XI through Vagus)

Differences b/w Infant & Adult ET • • • Infant 13 – 18 mm at birth. More horizontal – angle of 10°. No angulation at Isthmus. Bony part slightly longer & wider. Flaccid cartilage - reflux into ME. Less dense elastin at hinge – less recoil. • Less ostmann’s pad of fat Adult • 36 mm. • Angle of 45°. • Angulation present. • Bony – 1/3 rd, cartilage – 2/3 rd. • Rigid – protects ME from reflux. • Density of elastin more – helps to keep tube closed. • Large.

Functions • Ventilation & thus regulation of ME pressure. Air passes from ET to mesotympanum. Aeration Occurs when ET opens and nasopharyngeal air is exchanged with middle ear gases allowing for equalisation of pressures on both sides of TM. Opens 1. 4 times each minute lasting 0. 4 -0. 5 sec. - ET opens during yawning, swallowing & sneezing. - less effective in recumbent position. - poor function in young children.

• Protective functions - against reflux of nasopharyngeal secretions. – against high nasopharyngeal sound pressure. • During the periods when ET is open, secretions are prevented from entering the ear by back pressure of air within the middle ear space-gas cushion effect.

• prevents autophony Clearance of ME secretions. • cilia beat in direction of nasopharynx and helps to clear secretions and debris in middle ear towards nasopharynx by active opening and closing of the tube,

• either by 2 mechanisms: 1. mucociliary clearance by the ciliated epithelium. 2. muscular pumping occurs from isthmus towards the ET nasopharyngeal end when the TVP relaxes as tubal valve progressively closes.

ET Function tests • Valsalva test – build pressure in nasopharynx – air enters ET. • Politzer test. – in children unable to do valsalva. • Catheterisation. • Toyenbee’s test. • Tympanometry. • Radiological test. • Saccharine/ Methyline blue test. • Sonotubometry.

Tests for assessment of ET function: Valsalva’s manoeuvre - principle of test is to build positive pressure in nasopharynx so that air enters into ET. • note the movements of the TM. If air enters ME, TM moves outwards. In case of perforation, hissing sound can be heard, or crackling sound due to discharge. • Only 65%people can normally do this test. Avoid in case of active URTI , atrophic scar of TM. Politzerisation- done in children who cannot do valsalva method. • hissing sound is heard if tube is patent. It can also be used therapeutically to ventilate ME.

• In this 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 is closed, and the bag compressed while at the same time the patient swallows (he can be given sips of water) or says "ik, ik". • By means of an auscultation tube, connecting the patient's ear under test to that of the examiner, a hissing sound is heard if tube is patent.

ET catheterization • Entry of air into middle ear verified by auscultation tube. • In thi. S test, nose IS flr. St anaesthetised by topical spray of lignocaine and then a eustachian tube catheter, the tip of which is bent, is passed along the floor of nose till it reaches the nasopharynx. • Here it is rotated 90 medially and gradually pulled back till it engages on the posterior border of nasal septum • T

It is then rotated 180 laterally so that the tip lies against the tubal opening A Politzer's bag is now connected to the catheter and air insufflated. Entry of air in to the middle ear is verified by a auscultation tube.

• Complications: injury to ET opening can lead to scarring, bleeding from nose, transmission of nasal and nasopharyngeal infection into ME, rupture of atrophic area of TM due to high pressure

Toynbee manoeuvre • opposite of valsalva, note the movement of the TM- inward movement of TM, see thru otoscope;

Impedence audiometry- tympanometry- (inflation-deflation test) - positive and negative pressures are created in EAC. • Ability of tube to equilibrate positive and negative pressures to ambient pressure indicates normal tubal function. Can be done on intact or perforated TM. Radiological test Saccharine or methylene blue test

Sonotubometry • It Measures ET opening • using a speaker which produces a tone inside the nose. A microphone placed in the EAC such that opening of ET can be detected as an increased in the sound reception from nasopharynx. Tone is heard louder when tube is patent- tells duration for which tube remains open. Provides info on active tubal opening. Frenzel’s manoeuvre- nose and mouth of the pt is closed and ask the pt to move the tongue up against the palate against a closed glottis. Can hear click and note movements of TM

ET cannulation- fine cannula is passed into ET, connect cannula to politzer bag and auscultate after insufflating. In presence of fluid, gurgling sound can be heard by auscultation

Disorders of ET • Normally ET is closed. Opens with swallowing, yawning, & sneezing. • Acute tubal obstruction → absorption of ME gases → negative pressure in ME → retraction of TM → transudate in ME/ hemorrhage. ( acute OME).

Disorders of ET • Prolonged tubal obstruction/ blockage. → OME( thin watery/ mucoid discharge). → atelectatic ear/ perforation → retraction pocket / cholesteatoma → erosion of incudostapedial joint.

Causes of ET obstruction • • • URI. Allergy. Sinusitis. Nasal polypi. DNS. Hypertrophic adenoids. Nasopharyngeal tumor / mass. Cleft palate / Submucous cleft palate. Down syndrome.

CF of ET Obstruction • • Otalgia. Hearing loss. Tinnitus. Disturbances of equilibrium/ vertigo. • Retracted / congested TM. • Transudate behind TM.

Serous effusion

Retraction pockets

Cholesteatomas

Adenoids & ET obstruction • Mechanical obstruction. • Reservoir for infection. • Allergy – inflammatery edema. • Adenoidectomy can help in OME & recurrent otitis media.

Cleft palate • Abnormalities in torus tubarius – high elastin density. • Tensor veli palatani muscle does not insert into torus tubarius(in 40%), also function is poor. • Downs syndrome: - poor tone of T V Palatani muscle.

ME cleft ventilation • Air from ET → mesotympanum → attic → aditus → antrum & air cell system. • Anterior Isthmus – B/w Tendon of tensor tympani & Stapes. • Posterior Isthmus – B/w tendon stapedius muscle & pyramid, & short process of incus.

Obstruction of • ET – total atelectasis of TM. • In ME – retraction pocket in posterior part of ME. • Isthmi – attic retraction pocket. • Aditus – cholesterol granuloma & collection of mucoid discharge in mastoid air cells. • Other changes – thin atrophic TM, Cholesteatoma, Tympanosclerosis.

Patulous ET • Idiopathic, rapid weight loss, pregnancy, multiple sclerosis. • Autophony, TM may be moving even with respiration. • Acute condition is self limiting. • Weight gain, Potassium Iodide. • Cauterisation of tubes / Grommet.

Examination of ET • Pharyngeal end: Posterior Rhinoscopy, rigid nasal Endoscope, flexible nasopharyngoscope. • Tympanic end: Microscope / endoscope if TM is already perforated. - Intact TM – thinning OF TM, retracted TM, Cholesteatoma…

Otalgia – Local causes • External Ear – Furuncle, Impacted Wax, Otitis Externa, Otomycosis, Myringitis Bullosa, Herpes Zooster, & Malignant neoplasms. • Middle Ear – AOM, ET Obstruction, Mastoiditis, Extradural Abscess, Aero-Otitis media, & carcinoma.

Otalgia Referred causes • V Nerve: - Dental – Careis tooth, Apical Abscess, Impacted Molar, Malocclusion. - Oral Cavity – Benign/ Malignant / Ulcerative lesions. - TM Joint – Bruxism, Osteoarthritis, Recurrent Dislocation, Ill-Fitting Denture. - Sphenopalatine Neuralgia.

IX Nerve: • Oropharynx – Acute Tonsillitis, Peritonsillar Abscess, tonsillectomy. Benign / Malignant ulcers of Soft Palate, Tonsil & Pillars’ • Base of Tongue – TB / Malignancy • Elongated Styloid Process.

X Nerve: • Malignancy / Ulcerative lesions of – Vallecula, Epiglottis, Larynx, / Laryngopharynx, Oesophagus. C 2, C 3 Spinal N: • Cervical Spondylosis, Injuries of Cervical spine, Caries Spine.

• Psychogenic Causes: • Should be kept under observation.

Treatment • Otalgia is symptom. • Essential to find cause. • Specific treatment.