Page 50 - Problem-Based Feline Medicine

42 PART 1 CAT WITH UPPER RESPIRATORY TRACT SIGNS

Treatment Stertor occurs, which is worsened with excitement or
exercise.
Solid nasal tumors often respond well to external beam
radiotherapy, with survival times of 20–27 months. Diagnosis
Rhinotomy with turbinatectomy has been reported to
be successful. Acute onset of inspiratory dyspnea.
Often, there is extensive local invasion by the neo- Laryngoscopic inspection under heavy sedation or light
plasm, and the recurrence rate after radiotherapy with anesthesia with a rigid laryngoscope and blade reveals
or without surgery is high. erythema and edema of the laryngeal mucosa.

Nasal lymphoma responds well to standard chemother- Differential diagnosis
apy for lymphoma, with remission times of 16 months
reported. See page 676 for therapy. Laryngeal paralysis, laryngeal mass lesion or foreign
bodies may have similar signs, but are differentiated on
Pharyngeal and tracheal masses and nasopharyngeal
history and visualization of the larynx.
polyps (see page 37) are best addressed with surgical
resection. Treatment
Laryngeal tumors are difficult to resect and generally
Corticosteroids are indicated.
carry a poor prognosis.
● Dexamethasone (0.1–0.25 mg/kg IV or IM), or
prednisolone sodium succinate (10–30 mg/kg IV)
are good parenteral choices.
LARYNGEAL EDEMA
Antihistamines may be useful, but histamine release has
generally already occurred at the time of presentation.
Classical signs
Intubation or tracheostomy may be indicated in
● Inspiratory dyspnea.
severe situations.
● Stertorous breathing, stridor.
Prognosis

Pathogenesis Generally good, but severe obstruction, if untreated,
can be fatal. Laryngeal edema can also be a harbinger
Usually occurs secondary to an allergic reaction
of systemic anaphylaxis.
(type I hypersensitivity) from an insect sting, or fol-
lowing vaccination.
Prevention
Acute laryngeal edema occurs in some cats associated
with the intravenous anesthetic agent alfaxalone/alph- Avoidance of insect stings, access to poisonous plants
dolone (Saffan, Scherng-Plough) which is available in and caustic agents such as dishwashing powder and
Europe and other countries. The oil-based preparation cleaning agents.
causes histamine release.
Use of the new formulation of alfaxalone (Alsaxon-
Edema may be the result of laryngeal trauma, either CD, Turox, Australia), which is water-based.
blunt trauma to the throat, penetrating trauma (cat-bite
wound), or from the ingestion of sharp objects or LARYNGEAL STENOSIS
caustic materials (phenols, alkalis, acids) or plants
(poinsettias, philodendrons, dieffenbachia).
Classical signs
● Dyspnea and stridor on inspiration.
Clinical signs
● Common in cats after laryngeal trauma or
Inspiratory dyspnea, which may be associated with surgery.
severe respiratory distress and cyanosis.