What Will a Cat’s Face Look Like in Pain?
How to Read Pain in Mammal’s Faces
Research out of Dr. Mogill’s laboratory at McGill University in Canada, published in Nature Methods, (June 2010) studied mouse faces to see what the signs of pain were. The researchers injected a chemical into the mice to be certain they were in pain and adjusted cameras to capture their tiny little faces to see what changes they could see. We will discuss the features of a mouse in pain and then we will see how a cat in pain shows the same signs of pain in the face.
A mouse who is experiencing pain will tighten and hold muscles in and around his or her face in certain distinctive patterns.
Mice will bunch up their cheeks into tight little knots of pain. Their cheek fur sticks straight up underneath their eyes and does not lay smooth and flat on their faces. Cheek bunching indicates pain.
They squint their eyes. The mice look like they are looking out into bright sun, except they really don’t care to look at anything. They are not focussed outward, and their eyelids are almost shut. Combined with cheek bunching, eye squinting is a sure sign of pain.
They crinkle their nose up, with tiny mouse wrinkles on either side of the nose. This is akin to the cheek bunching, because some of the same muscles are involved. The result is a nose crinkling, cheek bunching, eye slitting mouse in pain. Obviously.
The mice lowered their whiskers and plastered them closer to their faces. They were not interacting with the environment.
Finally, they lower their ears. They scrunch their ears out flat like an airplane wing, or sometimes, even pull them down and back on the sides of their head. Surely, they are experiencing severe pain.
A truly fascinating observation by a pediatric oncologist led to the application of the face pain signals in mice to help children who cannot yet talk.
How Can You Tell a Child is in Pain?
Clinicians working with babies and very young children have a difficult time judging whether or not the child is in pain. If a child undergoing open heart surgery or chemotherapy, or other potentially painful experiences cannot speak, can you tell if they are in pain?
Signs of Pain in Pre-Verbal Children
The clinicians noted that many of these pre-verbal children would perform repetitive behaviors like toe tapping and punching their bed sheets in a rhythmic pattern. When the children were administered painkillers, the repetitive movements stopped. The doctors realized the children had experienced untreated pain!
Facial Signals: Cheek Bunching, Eye Squinting, Nose Crinkling
When the mouse research came out, the pediatric clinicians looked at the faces of the children with renewed vision. They saw cheek bunching, eye suiting, and a little bit of nose crinkling. The ears gave no clues; humans do not have the agile ear muscles of a mouse or a cat. We also, obviously, do not carry whiskers! For the parts of the face with identical muscling, the behavior was identical. Children and mice show pain in their faces in the same patterns!
Cats in Pain Hold Their Face Muscles Like Mice and Children in Pain
Your Truli read this research and then started looking at cats’ faces in a new light. Most people that grew up with cats, or have worked with tens or hundreds of cats, know instinctively when a cat is exhibiting pain. But how can you teach a pet parent how to judge whether or not their cat is in pain, without the personal relationship of guilt and clouded emotions getting in the way of accurate assessment of pain? And how can you teach new nurses, new doctors, and other healthcare workers? The more reliable and systematic the pain assessment, the more certain we can be that painkillers are needed.
Why not just give painkillers anyway, just in case?
Variable glucuronidation speed in different cats
Cats are sensitive to drugs. Non-steroidal anti-inflammatory painkillers (NSaids) are not processed (the process is called glucuronidation) in a cat’s liver reliably. The one NSaid US FDA-approved to treat postoperative pain in cats is only approved for one injection, with no repeated doses. Why? We know that the pain might last for 1-2 weeks, especially with orthopedic surgery?
Don’t Poison the Kitties With Painkillers!
The reason why is the variable rate at which the drug is processed in the cats’ livers. In the research trials, some cats processed half of the drug (the “half-life of the drug) in 24 hours, while other cats took one whole week to process half of the drug!!!! Repeated doses cannot be predicted when each cat should get the medicine. If your cat is a one day cat, then he needs more medicine the next day. If he is a one week cat, giving the medicine every day will give him seven times the therapeutic dose and poison him! If we have a reliable way to decide if a cat is in pain in the first place, we can decide whether to risk the medication for the comfort of the cat.
Only Risk Stressing a Cat When It Is Necessary
Cats also notoriously reject handling and medication administration. Sometimes the stress of administering the medication can make a cat hide, not eat, and become sicker. You want to be certain the stress is worth it!
Facial Signs of Pain in Cats
- Cheek bunching A cat will sit in a corner, withdrawn or even turned away. The cheeks will be bunched up under the eyes with the fur sticking up toward the eyes.
- Eye Squinting The cat’s eyes are slitted almost shut, or even completely shut. Even if you talk to the cat, or touch the cat, the cat will barely open the eyes. Really, he or she is focussed on the internal pain and not very focussed on the external world. This cat in the picture is behaving completely inappropriately for a busy, noisy hospital environment. Her eyes should be wide open, ears swiveling, head and ears up. Instead, she is showing pain in her face.
- Nose Crinkling Cat noses are tiny, bit f you look closely, you will see the cheeks bunched and the expression continues across the bridge of the nose. The crinkle cannot really be seen on this photo resolution. If you know cats, you can focus on her face. Do you see the relaxed anticipation, like a cat shows just before their dinner plate is set before them? Not at all!
- Whisker Lowering The cat’s whiskers are not out to the sides quivering and seeking clues from the environment. They are drooping low by the face.
- Ear Lowering The cat’s ears in the pictures are held out flat to the sides of her head. A normal, alert, happy cat puts their ears up, swivels the ear pines (flaps) to listen to the environment. A cat in pain is not thinking about protecting herself from the environment; she is just trying to withstand the pain. Nothing else matters to her!
Doc Truli administered painkillers just after the pictures. Rest assured, this story took far longer to write than it took to give this kitty effective opioid painkillers. She was in pain because of pancreatitis. After several days in the hospital in intensive care with intravenous fluids and special feedings, she made a full recovery.
Nature News article, with mouse face pictures, based on the Nature Methods original article (you’d have to pay for the original scientific article, if you wish to review it!)
There are huge ethics discussions online regarding this study. See IACUC.org to read about how studies are approved by researchers, community lay-people, and non-scientists at a university before the animals are ever involved.