Eustachain tube Flashcards
what does the eustachain tube connect?
Connects the middle ear to the post nasal space
what is the lining of the middle ear made of?
Lining of the middle ear is mucosa so it produces mucus.
when does the ET open?
Usually, tube is closed but opens when you swallow or chew etc.
When it opens mucus that accumulates in middle air drains and air moves freely between post nasal space and middle ear space, equilibrating the pressure between the post nasal space (atmospheric pressure) and the middle ear
why do your ears pop on an airplane?
Ear pops on airplane as Eustachian tube is normally closed.
Atmospheric pressure in airplane is lower so pressure in middle ear space is relatively higher. Popping happens when air is forced out of middle ear space
why is ET blockage common in children?
- Smaller = smaller diameter tubes, more likely to block
- Orientated differently = more likely blockage
- More coughs and colds = nasal lining is more inflamed
- Large adenoids that sit in post nasal space that can block tube
When the pressure in the middle ear increases, how does the tympanic membrane change shape?
Usually tympanic membrane is concave because air pressure inside is slightly lower than outside
When pressure in middle ear increases, this causes tympanic membrane to bulge e.g acute otitis media where excess inflammatory exudate is created in middle ear mucosa= increase middle ear pressure and causing it to bulge outwards so it looks convex in otoscope
what happens when the pressure in the middle ear decreases?
If pressure in middle ear decreases, tympanic membrane will retract e.g glue ear aka OME.
No pressure equilibrium between atmospheric and middle ear. Therefore air in middle ear space is reabsorbed, so just get fluid produced by fluid ear mucosa = negative middle ear pressure = TM is pulled inwards and becomes more concave.
Malleous will look more horizontal and TM will look duller as no air behind TM.
how can glue ear be treated?
Grommets are tubes put into TM. Provide alternate way of aerating the middle ear without having a patent ET.
why are central TM perforations considered safer than peripheral?
This is because the TM in the peripheral/attic part/pars flaccida isn’t under tension greater risk of complication arising in that area
what is the classic cholesteatoma discharge like?
blood stained and foul smelling
if you get persistent discharge in a TM perforation after AOM, what is it likely to be?
wet perforation or CSOM
NB dry perforations don’t produce any discharge
