Overview

• Formation of a thin but tough membrane at the choanae or anywhere above the soft palate, resulting in the occlusion of the caudal nasopharyngeal openings or narrowing of the orifice from a 1+ cm oval opening to a 1- to 2-mm opening or less.
• Inflammation secondary to chronic rhinitis, or from chronic regurgitation or vomiting of material into the nasopharynx should be considered as possible causes.
• Congenital narrowing or dysgenesis of the region is also suspected; thickened palatopharyngeal muscles have been reported as a cause of nasopharyngeal stenosis in the dachshund.

Signalment

• Cats of any breed or sex.
• Less commonly seen in dogs.
• Age-any age as long as ample time has passed since exposure to the inciting cause; congenital cases may present early or late in life.

Signs

• Evidence of upper respiratory obstruction
• Whistling or snoring sounds during respiration
• Open-mouth breathing
• Minimal nasal discharge in many cases
• Duration of signs for at least several months
• Aggravation of signs during eating or drinking
• Failure to respond to antibiotics or corticosteroids
• Absence of nasal airflow from one or both nares

Causes & Risk Factors

• Chronic upper respiratory disease.
• Foreign body or irritant contacting the affected area (perianesthetic regurgitation, reflux of gastric contents secondary to esophageal or gastric disease).

Differential Diagnosis

• Nasopharyngeal polyps-seen during oral examination or by radiography or endoscopy.
• Chronic rhinitis or sinusitis-moderate to severe nasal discharge and sneezing; obvious radiographic changes commonly seen.
• Foreign body-unilateral mucopurulent nasal discharge; radiographic abnormalities.
• Intranasal neoplasia-unilateral obstruction; nasal discharge often bloody; radiographic changes.
• Mycotic rhinitis-moderate-to-severe nasal discharge, often hemorrhagic; radiographic changes.
• Laryngeal disease-no improvement with open-mouth breathing; lack of snorting and nasal discharge; abnormalities on oral examination.

CBC/Biochemistry/Urinalysis

N/A

Imaging

• Near-normal radiographic findings.
• Nasopharyngeal stenosis sometimes can be visualized on computed tomography. Sagittal reconstruction of the images can be required.

Diagnostic Procedures

• Inability to pass a 3.5 French catheter through the ventral nasal meatus into the pharynx in a cat.
• Visualization of the stenosis by use of a retroflexed pediatric bronchoscope into the nasopharynx or use of an illuminated dental mirror.

Drug(s)

Antibiotics and steroids sometimes used post balloon dilation.

Contraindications/Possible Interactions

N/A