Page 40 - Problem-Based Feline Medicine

4. The cat with stridor or stertor

Jacquie Rand and Robert Allen Mason

KEY SIGNS

● Stridor.
● Snuffling.
● Snoring.

MECHANISM?
● Stridor is a harsh, high-pitched respiratory sound and stertor is a snoring sound created by upper
airway obstructive diseases, such as laryngeal obstruction. Airflow through a narrowed upper
airway has increased resistance and becomes more turbulent.
● With dynamic obstructions, such as laryngeal paralysis and tracheal collapse, the airflow
limitation occurs mainly during inspiration. Fixed obstructions, such as foreign objects and
mass lesions, affect airflow during both inspiration and expiration.

WHERE?
● Stridor or stertor arise from luminal narrowing in the upper airways, generally involving the
pharynx, soft palate, laryngeal structures and the upper trachea. Nasal stridor may also be
encountered.

WHAT?
● Most cats with respiratory stridor have nasal disease. Persians and Himalayans frequently have
respiratory stridor from stenotic nares. Chronic bacterial rhinitis following viral upper respiratory
tract infection, neoplasia or Cryptococcus infections are the most common acquired causes of stridor.

NASAL STRIDOR

QUICK REFERENCE SUMMARY
Diseases causing stridor or stertor
ANOMALY

● Stenosis of the external nares** (p 35)
Breed-related obstruction of the external nares (e.g. Persian cats) causes chronic snuffling and ster-
torous respiration.

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