Page 304 - Small Animal Internal Medicine, 6th Edition

276 PART II Respiratory System Disorders

thoroughly evaluated for structural abnormalities, foreign The normal diverse flora of the pharynx makes culture
bodies, or mass lesions. The length of the soft palate should results difficult or impossible to interpret. Bacterial growth
VetBooks.ir be assessed. The soft palate normally extends to the tip of the from abscess fluid or tissue obtained from granulomatous
lesions may represent infection.
epiglottis during inhalation. An elongated soft palate can
Obliteration of most of the airway lumen by collapse of
contribute to signs of upper airway obstruction.
As described in Chapter 14, the caudal nasopharynx the normal laryngeal structure is known as laryngeal collapse
should be evaluated for nasopharyngeal polyps, mass lesions, (Fig. 17.5). With prolonged upper airway obstruction, the
foreign bodies, and nasopharyngeal stenosis. Needles or soft tissues are sucked into the lumen by the increased nega-
other sharp objects may be buried in tissue, and careful tive pressure created as the dog or cat struggles to get air into
visual examination and palpation are required for detection. its lungs. Eversion of the laryngeal saccules, thickening and
Brachycephalic patients are evaluated for obstruction of the elongation of the soft palate, and inflammation with thicken-
internal nares by abnormal turbinate anatomy. ing of the pharyngeal mucosa can occur. The laryngeal car-
The trachea should be examined with a rigid or flexible tilages can become soft and deformed, unable to support the
endoscope if abnormalities are not identified on laryngos- soft tissues of the pharynx. It is unclear whether this chon-
copy in the dog or cat with signs of upper airway obstruction. dromalacia is a concurrent or secondary component of
If no endoscope is available, the laryngeal cartilages can be laryngeal collapse. Collapse most often occurs in dogs with
held open with an endotracheal tube for a cursory examina- brachycephalic airway syndrome but can also occur with any
tion of the proximal trachea. chronic obstructive disorder.
Neoplasia, granulomas, abscesses, or other masses can
occur within or external to the larynx or pharynx, causing Suggested Readings
compression or deviation of normal structures or both. Rudorf H, et al. The role of ultrasound in the assessment of
Severe, diffuse thickening of the laryngeal mucosa can be laryngeal paralysis in the dog. Vet Radiol Ultrasound. 2001;42:
caused by infiltrative neoplasia or obstructive laryngitis. 338.
Biopsy specimens for histologic examination should be Tobias KM, et al. Effects of doxapram HCl on laryngeal function of
obtained from any lesions to establish an accurate diagnosis normal dogs and dogs with naturally occurring laryngeal paraly-
because the prognoses for these diseases are quite different. sis. Vet Anaesth Analg. 2004;31:258.