Cornell Feline Health Center
Cornell University College of Veterinary Medicine
Ithaca, New York 14853
Labored and noisy breathing, nasal discharge, head shaking, sneezing, difficulty in swallowing—all of these clinical signs suggest that a cat is harboring an upper respiratory problem. In some cases, these signs may be accompanied by a phenomenon called “reverse sneezing”—a sudden, alarming, honking sound that the frustrated cat makes in an apparent effort to clear its throat. A veterinarian who notices such a startling noise is apt to conclude that the animal is trying desperately to dislodge some sort of obstruction from its throat. And if it’s a young cat —between eight months and one year of age or so—the veterinarian may well suspect the presence of a nasopharyngeal polyp, a noncancerous mass of tissue in the upper respiratory tract that develops most frequently in kittens or very young cats.
“We believe that this type of polyp is caused by inflammatory changes secondary to infection with a respiratory virus,” says James Flanders, DVM, associate professor of surgery at Cornell University’s College of Veterinary Medicine. “It might be a calicivirus, a herpesvirus, or any of the other types of viruses that cause sniffles in a young cat. The animal will be infected and will show the classic signs of upper respiratory distress. The signs will soon resolve, but some months later, the cat will start making this sneezing sort of noise and showing the other signs that a polyp has developed.”
Over the course of those months, it turns out, the respiratory virus has been stealthily circulating through the cat’s system, entering through the animal’s nose or mouth and following a circuitous route, passing through or lodging in the middle ear. The virus causes the tissue lining the middle ear to become inflamed and swollen, eventually prompting formation of a polyp. The middle ear soon becomes packed with the inflammatory tissue, and the engorged polyp may burst through to the ear drum. Or it may pass into the nasopharanx, the hollow area at the back of a cat’s mouth. In the nansopharanx, the polyp—a benign, superficial growth that is anchored to the inflamed tissue by means of a slender stalk—will continue to grow over a period of months until it starts interfering with the affected cat’s intake of air. “And that’s what causes the clinical signs,” says Dr. Flanders. “The cat thinks that there’s something stuck in the back of its throat—up above its palate—and when it tries to breathe through its nose, there’s an obstruction.”
Polyps can form bilaterally, he notes, and are especially dangerous if they become so large that they interfere with drainage from the nose. A definitive diagnosis is done by using a small blunt hook to probe beneath the back of a sedated cat’s palate; if a polyp is present, notes Dr. Flanders, “You can see it—a big, pink, fleshy mass.”
Treatment, he says, is always surgical. “The cat is anesthetized,” he says, “and the veterinarian will grab the polyp with a tiny forceps and yank it out. Its stalk will usually come out along with it. Simply pulling out the polyp will quite frequently be sufficient to remedy the problem.” Postsurgical treatment, notes Dr. Flanders, relies primarily on the short-term administration of antibiotics and perhaps oral steroids or ear drops to reduce the chance of recurrence.
By Tom Ewing
December 20, 2010