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Laryngeal paralysis usually occurs
in older dogs and horses. It sometimes
is referred as "roaring" or roarer's syndrome
in the horse. In the dog, paralysis of the larynx
or "voice box", usually results in noisy breathing,
excessive panting, decreased activity level, and decreased
in overall well-being.
In extreme cases, laryngeal paralysis can result in
decreased oxygen flow to the individual, resulting in
asphyxiation if not attended to quickly. What
is actually affected by this nerve paralysis are two
tissue folds that are located on either side of the
windpipe (trachea) opening, which function to open and
close in response to breathing or swallowing.
What causes laryngeal paralysis to occur.
Most cases are older dogs over the age of 8 years, and
usually affected are larger breed dogs (over 50 lbs),
although any dog is susceptible to this condition.
Sometimes associated with hypothyroidism, or other neuromuscular
diseases, often times the cause of laryngeal paralysis
remains unknown.
Blood tests are warranted on patients diagnosed with
laryngeal paralysis to determine if an underlying cause
exists. In the event that hypothyroidism or another
problem is discovered, treatment for that problem rarely
reverses the paralyzed larynx condition.
Mild cases involving only one side of the larynx, usually
fare quite well with rest and minimal exertion.
In cases with both sides of the larynx affected (bilateral
disease), symptoms are much more pronounced. These
patients also have a greater risk of asphyxiation if
they become stressed which can then result in an "air
hungry" individual.
Bilateral laryngeal paralysis patients in an "air
hungry" state, are exerting all their energy into
breathing in a forced manner. This leads to swelling
around the tissue folds of the larynx, which further
serves to block the flow of air. Treatment in
these cases involves passing a breathing tube by the
larynx (often requires sedation), allowing oxygen to
go directly to the lungs.
Drugs administered to these patients are designed to
reduce swelling in this area, as well as to reduce anxiety.
Often times sedatives are continued to prevent these
patients from relapsing into the "air hungry"
state again.
Surgical means of correction have been tried in patients
with bilateral laryngeal paralysis, in attempts to "open"
up or pull back these tissue folds in the larynx which
are blocking the flow of air. This results in
a wider opening to the windpipe, but the opening remains
wide during breathing and swallowing food and water.
Unfortunately, in virtually all cases in which this
surgery is performed, food and or water ends up
going into the lungs as a result of this wider opening,
which results in a condition known as aspiration pneumonia.
This type of pneumonia is very difficult to treat, and
often times treatment is unsuccessful for the patient.
Most cases of laryngeal paralysis are managed medically,
with medications that help reduce swelling in this area
of the larynx, as well as relaxing agents (sedatives)
to reduce anxiety in cases that appear "air hungry".
Broncho-dilators tend to open up the airways lower down
in the lungs, which can serve to better help oxygen
transfer for the patient.
Surgery should only be considered as a last resort
option, and only if medical management is not working.
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