By: Carl Jehn, DVM, MS, DACVS—Coral Springs Animal Hospital Surgeon
Brachycephalic
syndrome is a
combination of
anatomic abnormalities in the
upper airway of
brachycephalic
breeds.
Those
abnormalities
include stenotic
nares, enlarged
tonsils, elongated soft palate,
everted laryngeal saccules, narrow rima glottidis, and end-stage laryngeal collapse. These findings can occur individually or
in various combinations and vary in severity.
Figure 2
The normal anatomy of the upper respiratory
tract has been changed in affected animals
through breeding. The narrowed nares and
anatomy of the endoturbinalia are considered
to be the primary areas of stenosis; however,
the elongation of the soft palate may also play
a role as a primary component in airway obstruction. In order to obtain sufficient oxygen,
brachycephalics must produce higher negative pressure distal to the area of stenosis. This
draws soft tissues into the turbulent air way
which in turn results in inflammation and hyperplasia of those tissues. This further increases airway resistance resulting in a self-perpetuating
cycle which can eventually lead to laryngeal
collapse and finally suffocation.
The main clinical sign observed in these patients is severe dyspnea and exercise intolerance. Dogs may stretch their necks upward to
dilate the nasopharynx and larynx or lay in lateral recumbency to shift the soft palate lateral
to the epiglottis. These patients may also present with hyFigure 1 perthermia.
Initial
treatment in such
cas