CHAPTER 4

MECHANISM OF EUSTACHIAN TUBE IRRITATION

I believe that refluxing acid and digestive juices, coming up from the stomach, cause irritation of the tissues at the back of the nose and throat [called nasopharyngeal tissues] at the opening of the ET. See diagram Fig.4.1 above. Because of the infant’s allergic tendency, these tissues react excessively, producing swelling and mucus, narrowing or blocking the Eustachian tube.

Swelling at the opening of the Eustachian tube creates difficulty keeping the ET functioning normally. This makes it difficult for the infant to keep the middle ear at atmospheric pressure [see preceding chapter, about the ear]. Oxygen is absorbed from the ME, so a negative pressure develops. The body tries to prevent a vacuum forming, so if the pressure becomes very negative the lining cells of the ME produce mucus to fill the ME cavity. This is called an effusion, middle ear effusion [MEE] or ‘glue ear’.

There is evidence that the fluid usually contains some bacteria. Bacteria are always present in the back of the nose and throat where they have been filtered out by the nose to try to prevent them getting further into the body. When there is fluid in the middle ear cavity and the ET is blocked, the fluid has no way of escaping. This may provide a suitable environment for the bacteria to multiply, producing an ear infection [called acute otitis media (AOM)]. The rapid buildup of infection makes the ME produce even more fluid. The body sends more blood to the area to supply more immune function chemicals and white blood cells to help fight the infection. This makes the ear drum look red and pus forms in the ME. Because the ear drum is stretched rapidly it produces pain.

The fluid can remain in the middle ear and not develop into an acute ear infection [although some bacteria are usually present]. It may remain for a varying length of time. When fluid stays in the middle ear it affects the child’s hearing and there are many potential sequelae.

When babies with ETI first present to the doctor they may be at any stage of ear problems. Sometimes there is already ear infection with a red, bulging ear drum. Others may have fluid present but no obvious infection. Earlier, they may have mildly, moderately or markedly negative pressure. The ear drum may be retracted [pulled inwards by the negative pressure] if the ET dysfunction [ETD] is severe. However, if the negative pressure….



SUMMARY

Infants with Eustachian tube Irritation [ETI] have a combination of reflux and allergy [or an allergic background].

They may be suspected of having ETI if they have a combination of excessive irritability, feeding and/or sleeping problems, a desire to be upright and relief from sucking. The diagnosis may be confirmed by finding evidence of ET dysfunction [ETD] with negative pressures or middle ear effusion [MEE] or ear infection.

ETI may be mild, moderate or severe.

If ETI is mild it may be self limiting, settling by the time the infant is walking, without sequelae occurring.

If ETI is moderate there may continue to be problems related to ME infections or effusions, atopy or reflux but these may eventually settle. There is a risk of sequelae related to these problems but these may not be diagnosed until language development is noticed to be delayed or school learning problems become apparent.

If ETI is severe the child may have significant problems related to reflux, allergy and middle ear problems [MEE or ear infections]. These children are at high risk of developing sequelae and should be followed up to assess development. It is important to intervene as early as possible to reduce the child’s risks of developing sequelae. Sequelae are especially likely if the ETI was diagnosed late or treatment was delayed or inadequate.

Each child with ETI is different and the management depends on the individual child’s problems. It is necessary to deal with all aspects of ETI if results are to be satisfactory. Dealing with only one aspect is unlikely to produce major improvement….


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