Cat owners: Beware of polyps
A very interesting case came into my office recently, and alerted me to an issue that may be of note to cat owners in the area.
I treated a feline companion who had a nasopharyngeal polyp, which is a non-cancerous benign mass that does not often spread to other tissues, in the middle ear. Nasopharyngeal polyps develop in the compartment just behind the eardrum. As the polyps enlarge, they grow down the tube that connects the middle ear to back of the throat, called the eustachian tube. As the polyps continue to expand, they may partially block the cavity at the back of the mouth. Alternately, a polyp may grow through the eardrum into the ear canal, and in some cases will grow in both directions.
Nasopharyngeal polyps impact your cat’s breathing. The polyps obstruct the passage of air, so affected cats usually develop a distinctive snorting sound as they breathe. Secondary bacterial infections can develop due to the blockage and accumulation of secretions resulting in nasal discharge. The discharge may be clear or have some blood in it. If the polyp has extended into the ear, signs may include pawing at the ear, head shaking, head tilt or discharge from the ear. Cats can experience loss of balance and different pupil sizes, though it is rare.
No one definitely knows the cause of nasopharyngeal polyps. Some researchers believe that they may result in response to chronic inflammation. Nasopharyngeal polyps tend to occur in younger cats, frequently affecting kittens and cats younger than one.
Some polyps can be seen in the back of the mouth during an oral examination. The polyp may be hidden behind the soft palate, but in some cases it’s clear that there is something behind the soft palate pushing it forward. In cats with nasopharyngeal polyps growing out through the ear canal, the polyps may be visible on deep inspection of the ear canal and eardrum. Most cats must be sedated or anesthetized to perform a thorough examination. X-rays can help identify nasopharyngeal polyps, and a video endoscope may allow direct visualization of the polyp. A CT or MRI also help to visualize the extent of a polyp’s growth. The most common treatment of these polyps is surgery, which will generally improve your cat’s breathing and reduce other symptoms of polyps. Unfortunately, in most cases, it is anatomically impossible to remove the entire polyp, and recurrence is common. Some cats will require a more serious surgery known as a bulla osteotomy. This operation involves creating an opening into to the middle ear cavity by way of an incision in the rounded part of the skull just behind the ear, called the tympanic bulla. This approach allows removal of the source of the polyp, making it unlikely that the polyp will come back. This is the most effective treatment for preventing nasopharyngeal polyp recurrence, but it is a major surgical procedure and complications can occur.
Anti-inflammatory drugs such as corticosteroids may be used as an alternative to surgery, or in the post-operative period in an effort to control the inflammation that is thought to stimulate the growth of polyps. These drugs are much less effective at preventing recurrence than just treating the mass without surgery.
Most cats enjoy a relatively normal quality of life following standard polyp-removal surgery and experience few complications. In recurrent or severe cases, referral to a board-certified veterinary surgeon may be advisable. Your veterinarian will develop a treatment strategy based on your pet’s individual needs.