How to Measure Your Cat’s Pain Just by Looking at Her Face

By Dr. Karen Becker

When it comes to determining if your cat is in pain, the struggle is real — for both of you. As almost any cat parent can tell you, our feline friends are masterful at keeping their illnesses, aches and pains hidden from us.

This is by design, because while cats in the wild are accomplished hunters, smaller wildcats are also prey for larger animals. Showing illness, pain, or any vulnerability in that setting invites predation. That’s why your cat, and all cats, are wired to appear “normal” while dealing with significant illness or discomfort.

To complicate things further, since kitties tend to hide or keep to themselves when they’re not feeling well, it’s easy to misinterpret or simply overlook signs your furry family member is hurting.

The good news is that researchers are hard at work trying to solve this frustrating puzzle by developing tools both veterinarians and pet parents can use to decipher the body postures and behaviors most commonly seen in painful cats.

Interpreting Changes in Feline Facial Expressions as a Measure of Pain

A brand-new pain measurement tool for use with cats is the Feline Grimace Scale (FGS), which was recently validated, and the results published in the journal Scientific Reports.¹

To develop the scale, researchers at the University of Montreal conducted an observational, case-control study of 31 privately owned cats in pain and 20 pain-free control cats. The kitties were videotaped undisturbed in their cages, and the researchers assessed their facial expressions using screenshots from the videos.

Next, two observers independently compared screenshots of the two groups of cats (painful and pain-free) to evaluate differences in facial expressions. The researchers then categorized, tested, and scored five “facial action units” (ears, eyes, muzzle, whiskers, head) that signal pain in cats:²

• Ear position — Ears facing forward, ears slightly pulled apart, or ears flattened and rotated outward
• Orbital tightening — Eyes opened, eyes partially opened, or eyes squinted
• Muzzle tension — Muzzle relaxed (round), muzzle mildly tense, or muzzle tense (elliptical)
• Whisker position — Whiskers loose and curved, whiskers slightly curved or straight, or whiskers straight and moving forward
• Head position — Head above the shoulder line, head aligned with the shoulder line, or head below the shoulder line or tilted

Each facial action unit receives a score of 0, 1, or 2. A score of 0 indicates absence of pain in the facial action unit, 1 is moderate appearance of pain or uncertainty, and 2 is obvious appearance of pain. The maximum total score is 10; a total score of 4 or more means the cat is in pain and needs analgesia. You can see images of cats in which pain was absent, moderately present, or markedly present here.

The FGS was designed primarily for use by veterinarians, but the developers are working to validate its use with other veterinary care professionals as well as pet parents.

Your Cat’s Behavior Is Also a Window to His Pain

A 2016 study headed up by researchers at the School of Life Sciences at the University of Lincoln in the U.K. investigated signs of pain in cats.³ Signs of feline pain are primarily behavior-related, which is why I always encourage cat guardians to observe kitty’s behavior for signs of a problem.

The U.K. researchers surveyed an international panel of 19 veterinary experts across a variety of disciplines. The experts were first asked to list disorders they considered to be consistently, inherently painful in cats. Next, they were asked to evaluate pain-related behavior in cats according to the following criteria:

• Presence of the behavior in acute and/or chronic conditions and/or conditions not known to be painful
• Reliability of the behavior as an indicator of pain
• The likelihood the behavior would be present in a cat who is experiencing a low level of pain
• The likelihood the behavior would be present in a cat who is experiencing a high level of pain

Based on survey results, the researchers identified 25 signs considered sufficient to indicate pain. However, no single sign of the 25 was considered necessary for a cat to actually be in pain.

25 Signs Your Cat Is Hurting

The 25 behavioral signs considered by veterinary experts to be “reliable and sensitive for the assessment of pain in cats, across a range of different clinical conditions” are:

The researchers concluded:

“These results improve our knowledge of this topic, but further studies are necessary in order to evaluate their validity and clinical feasibility (especially in relation to different intensities of pain) to help vets and caregivers of cats recognize pain in this species effectively and as early as possible to maximise cat welfare.”

Another Pain Measurement Tool: The Feline Musculoskeletal Pain Index

Cats suspected of suffering with musculoskeletal pain are much easier to evaluate in their own homes vs. a veterinary clinic, because they’re less stressed and more likely to move around. The Feline Musculoskeletal Pain Index (FMPI) is designed to be used not only by veterinary staff, but more importantly, by cat owners.

“Using language accessible to cat owners, the questionnaire asks a series of simple questions about movement, behavior, sleep and mood,” writes feline practitioner Dr. Elizabeth Colleran.

“Pain associated with bones, joints and muscles results in compensatory behavior alterations that can be seen by a caregiver who’s known the cat for a period of time. A score is attached to the completed form which is used to evaluate the degree to which the cat has changed over time.”⁴

If you’re interested in the FMPI, visit PainFreeCats.org. The questionnaire can be downloaded or filled out online and repeated over time to see how your cat is progressing. It’s also important to discuss the results with your veterinarian. Since your cat’s health will naturally change over his lifetime, the FMPI can help you track trends, identify patterns of behavior, and make adjustments to his treatment protocol as necessary.

The Importance of Managing Your Cat’s Pain

As your kitty’s primary advocate, it’s important to realize that pain is a serious medical problem requiring treatment. Chronic pain can cause inactivity and loss of overall quality of life. It can also damage the bond you share with your cat if her personality or behavior changes or she becomes aggressive.

In addition, when pain isn’t managed effectively, it can progress from what we call adaptive pain — pain caused by a specific injury or condition — to pain that is maladaptive. Maladaptive pain can be of much longer duration than normal pain and considerably more challenging to treat. One of the best ways to avoid “pain wind up” from the beginning is to effectively address pain immediately.

I regularly see clients who are fearful of using appropriate pain drugs immediately after surgery (usually Buprenorphine) and opt instead for natural support. In my opinion, even the most potent herbs and nutraceuticals won’t address moderate to profound pain to the degree necessary to be considered humane, post-surgery.

After the patient’s pain is well managed on appropriate pharmaceuticals, the vast majority of cats can be weaned onto all-natural protocols (or a blended protocol including a reduced amount of pain killers) that do a great job of handling mild to moderate pain.

Alternative Approaches to Pain Management

Since felines are physiologically very unique, there are few effective pharmacologic agents that can be safely given long-term to control the pain of chronic conditions like arthritis.

Fortunately, there are a number of alternative therapies that can alleviate your kitty’s pain naturally, including chiropractic, therapeutic massage, stretching exercises, acupuncture, laser therapy, and the Assisi loop, which is a form of pulsed electromagnetic field therapy.

There are supplements that can be added to an arthritic cat’s diet to provide the raw materials for cartilage repair and maintenance and slow down progression of the disease. These include glucosamine sulfate, methylsulfonyl­me­thane (MSM), and eggshell membrane.

If your cat is overweight, it’s important to safely diet her down to a healthy weight to decrease the amount of inflammation in her body, since inflammation is a primary feature in all types of pain. It’s also important to feed an anti-inflammatory diet, which means eliminating pro-inflammatory foods that create inflammation and make the pain cycle worse.

Eliminate all grains in your cat’s diet, as well as foods in the nightshade family, such as potatoes, which are found in most grain-free cat foods. Grain-free processed diets aren’t carbohydrate-free, and carbs create an inflammatory response in cats.

Homeopathic remedies and nutraceuticals often work wonders for cats dealing with chronic pain, as does cannabidiol (CBD) oil. Many kitties also tolerate turmeric and omega-3 fatty acids, Esterified Fatty Acid Complex (EFAC), as well as boswellia added to their food, all of which help naturally reduce inflammation.

I recommend working with a integrative veterinarian to determine how to best treat chronic pain conditions in cats.