Hearing Problems in Cats and Dogs
Iíll bet that of all the "routine" health problems seen
by veterinarians on a daily basis, ear problems rank as the most frequent. Not
a day goes by in any animal hospital without a cat or dog being presented because
of itchy, inflamed, smelly, bloody or crusty ears. Why this is so is actually
an easy answer. What to do about the problems can be a real challenge.
Why do cats and dogs ears so commonly encounter difficulties?
The answer lies in the anatomy. If scientists wanted to design a perfect incubator
for growing and sustaining microorganisms and parasites, theyíd end up with
a dog or cat ear. Iím not talking about the ear flap, that floppy flag on the
bounding Cocker Spaniel and the erect sound reflectors standing atop you catís
The earflap is called the pinna and rarely presents problems for the pet.
An occasional dog is seen with what is termed a Hematoma of the pinna; a blood
vessel breaks over the cartilage of the earflap and a large blood deposit forms.
This can be treated with minor surgery.
But that incubatorÖthe tissues at the base of the pinna
and continuing down into the ear canal and eventually ending at the ear drumÖTHAT'S
a perfectly designed incubator, a perfect environment for microscopic life!
If that area gets enough air ventilation, does not have folds of tissue whose
surfaces contact one another, and isnít assaulted by dirt or irritating liquids,
a small and balanced population of bacteria exist naturally.
But natureís designs, although perfect for some organisms,
may be destructive for another. Letís take for example the Cocker Spaniel. Through
years of breeding the Cocker has evolved an ear canal that is rather long and
often even folds upon itself before reaching the ear drum. Often there are ridges
of ear canal tissue that course down the upper ear canal, which increases the
overall surface area... perfect acreage for growing all sorts of life. These
ridges restrict the drying effects of airflow.
So you can see that if we start
out with a structure that has too much mass for a small tubular canal, that
structure will be less than ideal for a healthy existence. Add to all this fact
that the ear canal isnít a canal at all. It dead-ends at the eardrum! Anything
that gains entrance to this ear "canal" will be pulled downward by gravity to
its termination at the eardrum.
If water gets into the ear canal, which doesnít necessarily
create any problems, that water has to evaporate to disappear. Because of restricted
airflow and the high humidity environment of the deep ear canal, that water
remains present much longer than it would in a dog with an open and airy ear
Bacteria have to have a water environment in order to multiply (thatís
why Freeze-Drying is such a good method of "preserving" things); and a wet,
warm, dark and nutritious soup awaits them deep in the Cockerís ear canal. Think
of the ear canal as a funnel with a wide opening at the top and a more and more
narrow diameter as you progress downward. NowÖ plug up the end of the funnel
with a delicate eardrum. Howís that for a collector of horrors?
As mentioned, there are normal types and numbers of bacteria
in any ear canal. When the wrong kinds of bacteria (Staphylococcus and Pseudomonas are notorious
criminals) meet with the wrong conditions (moisture, oils, dirt and secretions)
these bacteria can overwhelm the environment. Now the ear canalís thin surface
layers react to the organismís numbers and toxic waste products by secreting
more oils and fluids in an attempt to sooth itself. Inflammation results in
an increased blood supply (more heat) and chemicals are released onto and into
the tissues. Histamine is a notorious irritant and is released into the tissues,
which causes itching, and swelling and more tissue damageÖa vicious cycle ensues.
Now we have a dead-end canal that has restricted air circulation where even
more swelling and inflammation is occurring taking the situation even farther
from ideal. Whatís to be done?
Treatment of Ear Problems
Generally, at the first sign of a deep infection
in the ear canal, topical ointments or sprays are utilized to kill off the bacteria.
If the tissues are swollen and inflamed, oral antibiotics are used for ten days
to inhibit the bacteria from gaining access to the ear canal tissues.
As you can imagine, that topical ointment can add to the soup that is already present
in the canal so over infusing topical medications and ear washes can assist
in flushing the pus and debris out of that blind end.
Many dogs will need to
be sedated and given a thorough flushing and cleaning of the ear structures;
to do so when fully awake may be impossible.
Long term treatment should always
be a consideration because the conditions that allowed that first infection
to occur are still present and maybe the conditions have been made worse because
to that infection. Unsuccessful treatment is common.
Due in a major way to the
anatomy, but also because of the multitude of resistant bacterial, fungal, yeast
and parasitic organisms that enjoy living in the dog and cat ear canal, chronic
Otitis Externa may respond best to surgery. After all, if the predisposing
factor was an anatomy glitch, why not change that anatomy away from one that favors
organism growth? Why not open up that funnel and let some drying fresh air in?
Why not eliminate those folds and ridges and let that canal breath some fresh
Thatís where surgery comes in. Many, many dogs
have seen their quality of life improve vastly after surgery to open up the
ear canal. There are different procedures depending upon the severity of the
scar tissue and calcium deposits present and length of time the damage has been
going on. Each surgeryís intent, though, is to remove as much scarred and infected
tissue as possible, to eliminate folds and ridges, and to expose the deep area
of the canal to fresh air. If surgery is done early enough, the procedure goes
quickly and the amount of tissue to be removed is relatively small. Chronic,
long term Otitis Externa may require major reconstructive surgery.
In either type of case, the payoff comes quickly. The dog
heals rapidly and usually within two weeks the dog will actually let you know
how much better it feels. The painful infections are gone; the hearing is improved
(as long as the chronic infection didnít damage the ear drum); the smell disappears;
the medications lay unused; the dog can live in comfort without that continuous,
agonizing ear affliction.