Nasopharyngeal Polyps in Cats
Dr. Nicholas Trout
Nasopharyngeal polyps are benign growths that can occur in the pharynx (back of the throat), the middle ear and even perforate through the tympanic membrane (ear drum). The exact cause of nasopharyngeal polyps is uncertain. The problem occurs mainly in cats, with no known breed or sex predilection, and tends to be found in younger cats. The polyps appear to be the result of an inflammatory process and an underlying viral disease has been suggested but never proven. Snoring
Depending on the location of the polyp, the effect on the cat can be significant. In the pharynx, the polyp can interfere with breathing, eating and swallowing. In the middle ear, it can affect balance and hearing and can cause other neurological problems. In the ear canal, it can lead to a secondary bacterial infection with discharge and odor from the ear canal that will not resolve completely with antibiotics.
What to Watch For
Problems with balance
Ear infection that fails to respond to antibiotics
Your veterinarian will take a detailed history regarding your cat, followed by a physical examination. Particular attention is paid to the inside of the mouth and down the ear. Some cats will tolerate an otoscopic (ear) examination, but most cats require sedation or anesthesia to inspect their ear canal.
Polyps in the back of the throat often sit behind the soft palate and may also require sedation or anesthesia for a proper evaluation. If your cat is going to be anesthetized for a full evaluation, plain X-rays of his or her skull can also be taken to define the pharynx and the bulla, the middle ear at the base of your cat's skull.
A CT scan or MRI can help to visualize what is going on in the middle ear.
The final diagnosis is made when the polyp is removed and submitted to a pathologist for microscopic evaluation.
Removal by plucking. The polyp at the back of the pharynx may be plucked out, but there can be a tendency for it to grow back, particularly if it has extensions into the middle ear or the ear canal. There have been some reports of success in treating the polyps by plucking and then giving the cat oral steroids, but such reports have not been published at this time.
Surgical removal. If the bulla (the middle ear) shows abnormalities on an X-ray or a CT scan, then surgery should be performed to open the bulla and remove the polyp from that location. This surgery is called a bulla osteotomy. If the polyp has passed through the ear drum, then it should be removed from this location. This may necessitate ear surgery.
Home Care and Prevention
If your cat has a bulla osteotomy to remove the polyp from the middle ear, there will be an incision, usually on the underside of the neck, which will need to be monitored for swelling redness or discharge. Use an Elizabethan collar to prevent scratching at the neck region. The stitches must be removed in 10 to 14 days.
Your veterinarian will discuss the possible side effects of a bulla osteotomy prior to the surgery. These relate to some of the nerves intimate to the surgical procedure. Damage to these nerves, particularly affecting the eye, is not uncommon but is usually transient. Generally, it does not require specific treatment.
Following surgery there is a good possibility that the polyp problem will be resolved and not recur.
Since inflammatory nasopharyngeal polyps in cats are a disease of unknown origin, there is no good way to prevent the problem from occurring. The disease is best addressed as soon as clinical signs develop, before your cat becomes weak and anorexic from the mass in the pharynx, and before the polyp grows in the middle ear to cause severe neurological problems.