It's not always easy to tell if our pets are uncomfortable. They are often very stoic, and cats in particular are good at hiding signs that they're sore.
Interestingly, there have been some studies in rodents that suggest that sensitivity to pain and how well an individual responds to pain-relief drugs has a genetic component. Similar suggestions have been made about human beings' response to pain and analgesics. It wouldn't be surprising if in the future, a similar genetic link to pain response is found in our dogs and cats.
To help people identify subtle signs of discomfort in feline family members, researchers from Lincoln University asked specialists in feline medicine from around the world about how they evaluate pain in cats. The results were very interesting.
The study initially started by looking at feline facial expressions, but it was found that there were no facial expressions that were consistently associated with pain. The researchers then continued evaluating other symptoms and discovered that there wasn't one single indicator of pain in cats, but instead it was important to look at a number of behaviors. To this end, they developed a list of 25 behavioral signs that could indicate a cat was hurting. These signs include a lack of grooming, avoiding bright and sunlit areas, reluctance to jump, changes in eating patterns, and an arched or hunched-up body posture. Less obvious signs were changes in pupil size and ear position, as well as more rapid breathing.
What about dogs? While there hasn't been as thorough a review into signs of pain in dogs, a paper was published in 2003 by assistant professor Bernie D. Hansen of the North Carolina State University that discussed how to assess pain in dogs. It's generally thought that dogs are less pain tolerant than cats so it's perhaps easier to identify. They do tend to yelp or whimper that they're sore, or when touched, they have to change positions. However, they also have subtle signs that indicate that things aren't quite right. Look for changes in personality; they may be restless and unable to settle or even a bit grumpier than usual. Some dogs are just less interested in interacting with you and will generally keep to themselves. They may also pant more, lick their lips, and have wide eyes.
Don't be tempted to treat your hurting pet yourself. Human painkillers are great for us, but potentially deadly for dogs and cats. For example, acetaminophen will kill a cat, and ibuprofen will give dogs severe stomach ulcers. Your veterinarian can diagnose the cause of your pet's pain and treat them appropriately. Many pain-relieving medications are safe for pets, and some causes of pain will need additional treatment such as antibiotics.
Studies into pet pain and how it can best be relieved are important in maintaining their quality of life. Virtually all pets will have a painful experience in their life, even if it is something as routine as neuter surgery. By understanding how they express their discomfort and knowing the signs, we'll be in a much better position to keep them pain free.