Nasopharyngeal polyps are benign growths that arise from the mucous membranes of the nose (nasal) or the base of the eustachian tube (nasopharyngeal). Nasopharyngeal polyps can extend into the middle ear, external ear, pharynx (cavity behind the mouth) and nasal cavity.
The exact cause isn't entirely understood but it is believed that they are the result of chronic inflammation or congenital (present at birth). Young cats are most commonly affected, with a mean age of 1.5 years.
What are the symptoms of nasal and nasopharyngeal polyps in cats?
Symptoms vary, depending on the location of the polyps but may include;
- Chronic nasal discharge.
- Rapid shallow breathing (tachypnea).
- Head tilt.
- Horner's syndrome (drooping of the eyelid, constricted pupil, sunken eye and appearance of the third eyelid).
- Otitis externa (inflammation of the skin on the outer ear).
- Ear infection.
- Head shaking.
How are they diagnosed?
Diagnosis is based on finding polyps. Your veterinarian will perform a physical examination and obtain a medical history from you. Polyps can sometimes be seen or felt during an examination. This is performed under general anesthesia.
- Radiographs will reveal soft masses, increased density in the nasal cavity.
- CT scan can determine if the polyp extends into the middle ear.
- Rhinotomy will reveal masses and enable the veterinarian to biopsy material.
- Otoscopic examination.
- Biopsy of the removed tissue for a definitive diagnosis.
How are they treated?
Polyps at the back of the throat may be removed via the oral cavity by pulling with a slow and steady traction. Failure to remove all of the mass may result in regrowth.
Surgical removal of the polyps. If the polyps are within the bulla (middle ear), a bulla osteotomy will be necessary. This involves opening up the middle ear and removing the polyp(s).