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Surgical
Diseases of the Upper Airway
Collapsing Trachea
The trachea (windpipe) is
a rigid structure composed of numerous cartilaginous rings. In some small breed
dogs, particularly the miniature breeds, the cartilage of the trachea
degenerates over time. When this occurs, the trachea becomes soft and flaccid
and is prone to collapse during respiration. On inspiration, the cervical
trachea collapses. On expiration, the trachea in the chest collapses. It is
critical to diagnose not only tracheal collapse, but also the location of the
collapse.
The most common symptom of
collapsing trachea is a chronic, dry, hacking (honking) cough. In severe cases
there may be exercise intolerance, cyanosis, asphyxia, and death. Clinical signs
are often worse in hot and humid weather and are exacerbated by obesity and
concurrent airway problems.
A tentative diagnosis of
collapsing trachea is made based on history and physical examination. A cough
may be elicited on palpation of the trachea. Radiographs (x-rays) may
demonstrate the collapse. A definitive diagnosis may require the use of
fluoroscopy, an x-ray technique that allows the doctor to observe the trachea
during respiration in real time on a television screen.
Only the most severe cases
are treated surgically. Most respond to correction of the other problems noted
here or to medications. Weight loss and correction of concurrent airway
disorders may alleviate a significant portion of the problem. Cough suppressants
and antiinflammatory medications (corticosteroids) are often beneficial as is
avoidance of stress and environmental irritants.
Brachycephalic Airway
Syndrome
The upper airway in dogs
consists of the nose, sinuses, pharynx, and larynx. There are a variety of
problems that can affect the upper airway and compromise the normal flow of air.
A particular set of upper airway abnormalities affects brachycephalic dogs. The
term "brachycephalic" refers to dogs with shortened noses and mouths. Bulldogs,
Pekingese, and Pugs are examples of brachycephalic dogs. Problems seen in
brachycephalic breeds include stenotic nares, everted laryngeal saccules, and
elongated soft palates. These dogs can have any or all of these conditions.
Sometimes these problems compromise respiration to such an extent that surgical
intervention is required.
Symptoms of brachycephalic
airway syndrome include the following:
Symptoms are often worse
during hot and humid weather. Obesity can also worsen clinical signs.
A diagnosis is made by
visual examination of the nares, soft palate, and larynx. Laryngeal examinations
may need to be performed with the aid of sedation or anesthesia.
Stenotic Nares
(Abnormally Narrow Nostrils)
The nares (nostrils) of
brachycephalic dogs are often too narrow to permit normal respiration. These
dogs tend to breathe exclusively through their mouths or make wheezing sounds
when breathing with their mouths closed. The treatment of choice for this
problem is a surgical procedure called rhinoplasty. When performing a
rhinoplasty, a small wedge of tissue is resected from the side of each nostril.
The remaining tissue is then sutured together, effectively widening the opening
of the nares and allowing for more normal respiration.
Everted Laryngeal
Saccules
The laryngeal saccules are
small bags of tissue that normally sit in recessions just in front of the vocal
folds. When we breathe normally, we decrease the pressure in our lungs and upper
airways by expanding our chests. This action allows air to flow down our airways
and into our lungs. Dogs with compromised airflow through the upper airway must
work harder to fill their lungs with air. This decreases the pressure in the
upper airway even more and literally pulls the saccules into the airway. When
everted, the saccules sit just in front of the opening to the trachea and block
the flow of air. The treatment for this problem is excision (removal) of the
saccule tissue.
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