Page 42 - Problem-Based Feline Medicine

34 PART 1 CAT WITH UPPER RESPIRATORY TRACT SIGNS

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STRIDOR FROM PHARYNGEAL, LARYNGEAL OR TRACHEAL AREA

Degenerative:

● Laryngeal paralysis (p 43)
Generally neurogenic paresis/paralysis of the abductor muscles of the arytenoid cartilages of the
larynx. Often idiopathic, although traumatic causes are reported. Inspiratory dyspnea with stertor
(snoring sounds) or stridor (whistling obstructive sounds) is the hallmark of laryngeal paralysis.
Changes in voice and character of purring are often reported by owner.
● Tracheobronchial collapse (p 44)
Harsh, “honking” cough caused by degeneration of the cartilage support of the large airway walls.
If upper cervical trachea is involved, stridor may be present. Rare in cats.
Anomaly:
● Congenital anomalies of the upper respiratory tract* (p 39)
Dyspnea usually indicates fixed obstruction (inspiratory and expiratory) because of the stenotic
nature of most defects. Inspiratory dyspnea, stertor and stridor occur with the brachycephalic syn-
drome.
Mechanical:
● Airway foreign bodies (p 40)
Harsh, productive cough and acute dyspnea occur with foreign objects that have been inhaled,
regurgitated or aspirated into the nasopharynx, trachea or bronchi. Stridor is noted when the foreign
body is lodged in the larynx or trachea. Nasal foreign bodies create a form of stridor that has a more
whistling character than laryngeal stridor. Sneezing and nasal discharge are common with nasal
foreign bodies.
Neoplastic:
● Airway tumors (p 41)
Signs depend on the site of the tumor. Nasal tumors causing obstruction may produce stridor and
open-mouth breathing. Pharyngeal tumors causing obstruction may result in dysphagia, stridor,
stertor and voice changes. Tracheal tumors result in a fixed obstruction, and inspiratory and expira-
tory dyspnea, stridor and commonly a cough.
Inflammation:

● Laryngeal edema (p 42)
Usually occur secondary to an allergic reaction, following alphaxalone/alphdolone anesthesia or
laryngeal trauma. Signs include inspiratory dyspnea and stertorous breathing or stridor.
● Laryngeal stenosis (p 42)
Common in cats after laryngeal trauma or surgery. Results in dyspnea and stridor on inspiration.
● Laryngeal eosinophilic granuloma (p 45)
Occurs weeks or months after signs of viral upper respiratory tract infection. Signs include stridor
from the laryngeal region and swollen, edematous arytenoid cartilages of larynx.