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Pre-Surgical Information
Spaying or neutering your pet is a big step! There is a lot to consider
when we are planning your pet’s surgery. Here is some information to help
you make wise decisions.
Click here . . .
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Special LibraryOur Special Library
is a collection of informative articles on a variety of health topics.
Click here . . .
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Discharge InstructionsClick here for
information on how to care for your pet at home.
Click here . . .
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Ear Diseases
Ear disease is very common
in the dog. Early action is very
important in order to keep the
infection from becoming permanent.
Ear disease is very common in dogs, and much less common in
cats. Ear infections in dogs and cats really do not have
much in common with ear infections in people. A review of the
anatomy is a good place to start in our quest to understand ear
disease in pets.
The part of the ear that does the hearing is called the inner
ear. It is very delicate, and is buried deep inside the
skull for protection. It is not well-labled in the image
at the right, but the inner ear is the Cochlea.
The Inner Ear is run by some mechanical parts that are contained
in the middle ear. The middle ear is an air-filled,
drum-like hollow space. There are some bones present,
called the auditory ossicles, that transmit sound vibrations
from the ear drum, or tympanic membrane, to the inner ear.
The rest of the ear is a collecting funnel that collects sound
and funnels it down to the tympanic mambrane. The ear
canal is a tube that runs from the outside to the inside and
ends at the tympanic membrane. In dogs and cats, the ear
canal has two parts. The vertical canal runs up and down,
then
 makes
a right angle bend and becomes the horizontal canal.
The ear canals are lined with a special type of skin. This
skin has special glands in it that make ear wax, also
called cerumen by the
 medical
types. The skin also has billions of microscopic cilia.
Cilia are tiny hairs that beat in waves, kind of like sports
fans sitting in a stadium. This wave action is what keeps
the cerumen from collecting in and plugging up the ear canal.
The cilia wave the ear wax towards the outside.
Living happily inside the ear canal along with the cilia and the cerumen are various bacteria and also some yeast. These
bacteria and yeast are normal, and are present in all dogs and
cats. They are there in low numbers, because the ear is
healthy and happy, the cilia are working, and the cerumen galnds
are doing their job too.
Something has to happen to upset the balance for an ear
infection to occur. There are many things that can do
this. A partial list follows:
Allergies
Grass Awns
Water in the ears
Bad Genetics
Ear Mites
Bad Luck
Sometimes it is a combination of two or more things.
Sometimes we are not able to identify the cause.
What dogs most commonly end up with is an infection in the ear
canal. This is called otitis externa, and is quite
different from the ear infections children get. Children
get infections on the other side of the ear drum, in the middle
ear. Otitis externa is itchy and may even burn, but I do
not believe dogs feel the pressure and pain (in the middle of
the night!) that children feel with ear ac hes.
Not that otitis externa is fun. It
 really
bothers dogs, and they show their discomfort by shaking their
heads, scratching their ears (sometimes to the point of
bleeding), carrying one ear low, etc.
In the images, normal is on the right, infected is on the left.
To treat otitis externa, it is important to know the enemy.
There are three main types of things that can grow in infected
ears: Round bacteria, rod-shaped bacteria, and yeast.
It is important to know what we have, because it can take
different medications to kill each type of problem. To
find out what is growing in your dog's ears, we take a swab of
the goo in the ear, put it under the microscope, and look at it
under high magnification. Then an appropriate drug can be
prescribed.
If ear infections are not treated promptly, they get worse.
If an ear is infected for months, the
 infection
can cross the ear drum and enter the middle ear. If this
happens, ear drops are not going to solve the problem because
they can't get across the ear drum. Also, pus builds up in
the middle ear, and unless it is removed, the infection will
never go away. And that's not all. If an ear stays
infected for months, the special skin that lines the ear canal
changes in response to the infection. While it would be
convenient if the skin would change in a way that made it better
able to fight the infection, that is the opposite of what really
happens. The canals swell, sometimes completely shut.
The cilia disappear. The cerumen glands get hyperactive.
This leads to poor drainage, accumulation of cerumen, and the
bacteria and yeast just go wild in that environment. If
the infection stays long enough, these changes become permanent,
and the ear may never be totally healthy again.
One of the worst things you can do to your dog's ears
is under-diagnose and over-treat. This usually happens in
dogs that have recurring ear problems. Many owners just
want to get some more of the same old medicine and put that in
whenever the ears flare up, rather than address the underlying
problems. We see quite a few dogs as second (or third or
fourth) opinions who have been on Otomax (a commonly prescribed
ear drop that I hate) for years. Many of them have
underlying allergy problems. Others have middle ear
infections. Others have just plain bad genetics. But
the point is that by the time I see them, their ears are
end-stage, meaning that the canals have undergone permanent
changes, meaning that nobody can fix those ears medically. Click
here for a link to a discussion of surgical ear treatments.
If your dog has more than two episodes of ear problems a year,
or even if he or she has only two episodes a year but has them
every year, we need to address the underlying problems before
the ear infections become permanent. Allergy medication,
ear washes, and or middle ear lavage can all help restore your
dog's ears to health, but only if done in time.
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