Page 49 - Problem-Based Feline Medicine

4 – THE CAT WITH STRIDOR OR STERTOR 41

Signs of fixed obstruction occur with nasal and tra- See reference on page 23 for details (The Cat With
cheobronchial foreign bodies because airflow is limited Signs of Chronic Nasal Disease).
during inspiration and expiration due to constant partial
obstruction of the airway. This may result in increased
Pathogenesis
breathing sounds, and often stridor and dyspnea during
inspiration and expiration. Nasal tumors are most commonly squamous cell carci-
noma (SCC) of the nasal planum, solid nasal carcino-
Typically nasal foreign bodies have sneezing, stridor
mas and nasal lymphoma.
and pawing or rubbing of the face, while pharyngeal
and tracheobronchial foreign bodies present with SCCs of the tonsil are common pharyngeal masses,
coughing, stridor, gagging or retching, pawing at the along with benign nasopharyngeal polyps.
mouth, salivation and dyspnea. Typically the signs are
Tracheal tumors consist of lymphoma, SCC, leiomyosar-
frequent, marked and have a sudden onset.
coma and osteochondral tumors from the tracheal rings.
Adenocarcinomas have increased prevalence in the
Diagnosis
Siamese.
Some nasal and most tracheal foreign bodies may be
Lymphosarcoma and squamous cell carcinomas are the
seen radiographically.
most frequent tumor types involving the larynx.
Rhinoscopy and tracheobronchoscopy can be both
diagnostic and therapeutic. Rigid tracheoscopy allows
Clinical signs
for larger retrieval instruments to be utilized than with
flexible endoscopy. Nasal obstruction produces stridor, open-mouth
breathing, unilateral nasal discharge and cough-
Differential diagnosis ing from post-nasal drip. Anosmia may lead to inappe-
tence.
Nasopharyngeal polyps may cause similar signs of
nasal obstruction and sneezing, but tend to have a more Pharyngeal masses produce dysphagia, stridor, ster-
chronic course. torous dyspnea and voice changes. Fetid halitosis is
also reported.
Tracheal or bronchial neoplasia may have similar
signs, but again are more chronic in nature and can be Tracheal tumors cause fixed obstruction, leading to
distinguished bronchoscopically. both inspiratory and expiratory dyspnea with stridor,
which is often louder on inspiration. A harsh, dry
Treatment cough is common.

Removal of the foreign body, either surgically or
endoscopically, is often curative. Nasal foreign bodies Diagnosis
may be endoscopically retrieved or hydropulsed, but
Diagnosis is made via rhinoscopy, pharyngoscopy or
occasionally require surgical rhinotomy.
tracheoscopy with biopsy. It is possible to image soft
tissue masses radiographically, but endoscopy is still
AIRWAY TUMORS
advised for biopsy. Other imaging modalities (CT and
MRI) provide excellent images and aid in surgical and
Classical signs
radiotherapy planning.
● Nasal obstruction: stridor, open-mouth
breathing. Differential diagnosis
● Pharyngeal obstruction: dysphagia, stridor,
stertor and voice changes. Inhaled and penetrating foreign bodies may produce
● Tracheal tumors: fixed obstruction, similar signs, but usually have a history of acute onset.
inspiratory and expiratory dyspnea and Benign or parasitic granulomas of the airways may
stridor. Cough is common. mimic neoplastic masses but can be differentiated on
biopsy.