Mystery of Nasopharyngeal Stenosis

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Although recovered from an upper respiratory tract infection as a kitten, many cats would still display obvious nasal noise while breathing; furthermore, they would even show open-mouth breathing or paradoxical breathing when they are too excited. Strangely, these cats may not have any nasal discharge, and those symptoms remain more or less the same. What is going on?

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Nasopharyngeal stenosis is one of the possible causes of such symptoms.

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Nasopharyngeal stenosis in cats is usually an acquired condition. The pathogenic mechanism of such a condition is still unclear; however, most literatures suggest that a part of respiratory mucosa is under chronic irritation (e.g., infection, trauma) which results in subsequent repairing, adhesion, and formation of scar tissue, leading to narrowing and blockage of the nasopharyngeal passageway.

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Diagnosis of nasopharyngeal stenosis is rather straightforward, either with a Nasopharyngeal Endoscope or Computed Tomography (CT) will do, yet treatment is more complicated. Treatment options include balloon dilatation, surgical removal of the stenotic region with soft palate resection, temporary stent placement, laser scar revision, etc. The recurrence rate of treatment with balloon dilatation alone is quite high (41%)(Reference 1), as well as those cats with chronic respiratory infections. However, with thorough evaluations and planning, many patients are able to achieve good results after a single surgery.

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Well, what will happen if my cat receives no treatment at all?

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Many cats displaying open-mouth breathing, together with abdominal breathing or sleeping disorder, often only have a nasopharyngeal opening of a size pinhole. Hiatal hernia as a common comorbidity would further result in frequent vomiting and reflux. Over time if the thoracic pressure remains abnormally high, it may progress to cardiovascular disorders e.g., right heart failure!