Now let's talk about disorders
that affect the ear.
Let's start with otitis media.
This is an ear infection behind
the eardrum in the middle ear.
This can be acute or chronic.
This cause a lot of pain.
And they commonly occur after a patient has had
a primary viral illness such as the common cold
and then a secondary bacterial
infection will develop.
Some of the causes of ear
infections are vaccine-preventable.
Ear infections are not contagious.
They won't spread from person to person
but they can translocate within the host
which means your patient with an ear infection may
have the spread of the infection to another area.
Worldwide, acute otitis media affects
about 11 percent of people a year.
This is hundreds of millions of cases.
Half of the cases involve children less than 5 years
of age and it's more common among male patients.
Here's the anatomy of the external ear which includes
the part that we think of as the "actual ear"
and that includes the ear canal
The middle ear space begins behind the eardrum.
Here you will find the bones that
transmit the sound for hearing
and the eustachean tubes which help
regulate the fluid in the middle ear.
When the eustachean tube isn't functioning properly,
the gas volume in the middle ear is trapped
and this causes a negative
pressure in the middle ear.
The fluid from the surrounding tissue is then pulled into that
space causing an effusion or extra fluid behind the eardrum
If you can't clear that fluid out of
that space, it may get infected.
Dysfunction of the eustachean tube is a
common cause of all forms of otitis media.
This is usually due to inflammation of
the mucus membranes and the nasopharynx
This can be caused by common viral illnesses such as the
common cold, strep throat, or even seasonal allergies.
Typically, we see the patients start with a viral URI
Again, if they don't clear
the fluid out of the space,
bacteria can begin to grow and this is
called the secondary bacteral infection.
Pediatric anatomy and their immune
function contributes to this problem.
The three most common causes of
bacterial pediatric infections are:
Strep pneumoniae, M. catarrhalis
and Haemophilus influenzae
Here you can see the pus from the infection
pressing up against the back of the eardrum.
That's gonna make it bulge out into the canal.
There are some risk factors for ear infections.
One is second-hand smoke exposure.
Another is pacifier use and
children who attend daycare.
And this could be, they're
just exposed to more viruses.
But then if they're not cleared, the fluid
can turn into a bacterial infection.
Here are some differences in the anatomy.
On the left we see the infant's eustachean tube,
on the right we see the adult eustachean tube.
The size of the passageway contributes to the problem,
so infants have a much smaller eustachean tube.
The direction of the drainage into
the throat is also different.
In pediatric patients, the tube lays more horizontally and
this makes it easier for bacteria to ascend the tube.
In adults, this is more vertical
so they're assisted by gravity.
Bacteria actually need to climb up like a ladder.
The stiffness of the tube has to do with this too.
In children, the tube is softer, therefore it's more
collapsible and the fluid can get trapped inside
Adults have a stiffer eustachean tube.
The length of the tube also contributes.
Pediatric patients have a shorter distance for the
bacteria to travel and adults have a longer distance.
The opening into the throat is also rounder in pediatric
patients and this allows a bare passageway for the bacteria.