Ron Hines DVM PhD
Why Are There Less Pain Control Options For My Cat Than There Are For Dogs and Humans?
There are three reasons that that is true:
The first is that vets have noticed over the years that cats can be sensitive to a number of drugs that dogs and us humans take with few, to no, side effects. That’s chiefly because the liver of cats is naturally deficient in a number of enzyme systems (metabolic pathways) that allow their bodies to purge themselves of specific drugs. (ref1, ref2, ref3, ref4)
The second reason is economics. Drug companies develop and market veterinary medicines to make money. Bringing a new drug to market is costly. These companies know that the typical dog owner is willing to spend more money on their pet than the typical cat owner. In a 2017 LendEDU poll sent to 250 American dog owners and 250 cat owners, one question was “How much would you be willing to spend to save your pet from a life-threatening illness?” Dog owner’s responses averaged $10,725.46; but cat owners only averaged $3,454.22. In a 2016 UK Telegraph poll, dog owners spent an average of £60 a month on their dog; while cat owners only £47 on their cat. Food costs accounted for some of that discrepancy – but not all of it. A 2017 US pet industry trade group, found that the average money spent on veterinary care for dogs was $257; that for cats $182.
The third and most important reason is that cats can’t talk. It is very difficult for vets, or owners, to determine if a cat is actually in pain. Dogs are non-verbal too; but they are considerably more likely than cats to limp or show postural or locomotion changes when they have bone, joint or tissue issues. Cats rarely change their facial expression, body language or beg for compassion the way dogs do when they face health issues. Cats are more stoic in those situations. Some attribute this to the fact that the ancestors of our house cats (unlike dogs and humans) were solitary creatures with no need to express their feeling to other members of their group. I do not know how much of that is true, but it is plausible.
Is There More Than One Type Of Pain?
Yes, there are two – acute or sudden pain, and chronic or long-term pain.
They are quite different in how they are relayed to the brain and processed after they get there – and in their long-term consequences to the quality of your pet’s life. Pain has been extensively studied in humans (ref) and laboratory animals (ref) – but hardly at all in cats or dogs. Other than being uncomfortable, acute pain and chronic pain have very little in common. In persistent (chronic) pain, brain messenger circuits are actually mechanically and chemically altered. Some circuit pathways are fortified (strengthened) while others become less involved. With time, pain perception alters, as does mood. The brain’s own pain control chemicals (endorphins) become depleted and pain becomes more difficult to control with medications that worked before.
Short Term Pain
All animals are better equipped to deal naturally with short term than long term pain. The source of most short-term pain: a minor traumatic injury, a bite, a superficial puncture, thorn or infections, a minor burn, etc. gradually heals and the pain goes away. During that time, pain can be quite protective. Limited use, resting and decreased activity give wounds their best chance to heal efficiently. Because short-term pain is not all negative attempts to eliminate it can be overdone. For example, the inflammation that accompanies most sources of inflammation and surgical pain encourages immune system cells at the wound site to send messages to the brain to release pain-alleviating endorphins (the body’s own narcotics). (ref1, ref2) But when acute sudden pain morphs over time into chronic pain, that endorphin releasing system breaks down. (ref)
There is currently a lot of discussion among veterinarians that perhaps we should deal with short-term pain in cats more intensively than we generally do. Most veterinarians now give cats in these situations post or presurgical medications to minimize pain. (ref) Some even evangelize to carry these control procedures to the extreme. My philosophy is that our goal is to minimized, not eliminate, short-term pain – when the drugs used are not detrimental to the pet’s recovery and general health.
Long Term / Chronic Pain
Some of the sources of short-term pain do not heal. With time, and continuing stimulation, the pain morphs into its chronic form. In those cases, brain circuits and spinal nerve pathways change (brain/spine network alterations). The perceptions those pain signals generate also change. Medications that worked well at first often loose their effectiveness as well; and drugs that alter mood must sometimes be thrown into the mix as well. These changes have been studied extensively in humans (ref) and rodents. (ref1, ref2) but not in cats.
Most veterinarians believe that the most common cause of long-term chronic pain in cats is arthritis (ref1, ref2) and cancer. (ref1, ref2) One 2002 study claimed that in a group of one hundred cats over the age of twelve, 90% had x-ray evidence of arthritis. (ref) X-rays are a good way for your veterinarian to confirm arthritis – but a poor way to confirm pain. It has long been known that in humans the amount of arthritis or joint injury seen on x-rays does not correlate well with the amount of pain experienced. That is, some folks with marked arthritis changes on their x-rays report only a little pain while some folks with very little changes report a lot of pain. (ref)
What Are Some Signs That My Cat Might Be In Pain?
First of all, I believe that an accurate determination that a cat is in pain is best done by you – the cat’s owner – not your cat’s veterinarian. We all know that cats act quite differently with strangers and in unfamiliar situations. Since cats can’t talk, one can only come to general conclusions based on hints – similar to situations that occur in non-verbal people. (ref)
I would be unlikely to begin treating a cat for pain when the owner(s) of that treasured cat did not feel that their cat was in pain and I saw no evidence of it on my exam. I would be considerably more likely to treat the cat for pain if the owner thought the pet was in pain but I saw no evidence of pain on my examinations. But there are plenty of veterinarians who take a more authoritarian, less passive, position than I do. (ref) There are also quite a few veterinarians who – finding little evidence of pain during their examination – would say “Well, I’d be experiencing pain if I were in this cat’s situation. True, I don’t see any evidence of pain. So this cat must be hiding its pain. We’ll treat it anyway.” That approach is particularly prevalent at teaching veterinary colleges and institutions sensitive to correctness and the public pulse.
Here are some things you should look for when making your decision. Do keep in mind that for every one of these signs, there are alternative health and psychological explanations other than pain that could produce identical signs. But taken together, particularly in the absence of other exam findings that would explain them, these signs are things that would make me suspicious that pain is involved:
Cats are creatures of habit. Your cat has favorite sitting positions. Have they changed? Is your cat lying on its side more or less? Are its legs more extended and tense than they used to be? Does your cat seem more restless?
There are veterinarians who attempt to quantify these sort of changes into questionnaire forms. They have not been particularly successful. (ref1, ref2)
Your cat is a creature of habit. Once it establishes a household routine, it rarely changes that routine unless its environment, health or human/animal interactions change. So any change in your adult cat’s behavior, when no change has occurred in its environment, is often do to a change in its health. Those changes can be very subtle. Dogs are more likely to display their painful feelings – perhaps to solicit the sympathy of their owner. The cats I have owned rarely did. Being cats, it was just not in their nature to do so.
The sign of pain most likely to occur in cats is reduced mobility – a reluctance or disinclination to move about the house in their normal daily routine. A reluctance to jump up on the bed or a couch is often the first sign cat owners mention to me. Now any sort of acute pain or chronic joint pain can cause that; but the most common cause in older cats is generalized arthritis. Cats with joint issues are much less likely to limp than dogs are. If your house has more than one level, you might notice that your cat is spending more time downstairs than it once did. Potty accidents outside of the litter box (when not due to urinary tract disease, inter-cat conflicts or new stress factors in the household) can also be due to pain – with arthritis again the leading suspect as cats age. The same goes for a loss of interest in their every-day activities. Things like less playfulness or less interest in their toys. A change to growling or biting when the cat is stroked, carried or manipulated is also often a sign of pain.
Due to the challenges of diagnosing arthritis in cats, it is difficult to know how many cats in the USA are affected. The only study I know of looked at radiographs (x-rays) of older cats and produced startling results. In that 2002 study, 90% of cats over 12 years of age had some evidence of degenerative joint disease or spinal arthritis (spondylosis ). X-rays showed that their shoulders, hip joints, elbows, knees and ankles were the areas most commonly affected. (rptref) A 2010 study reported similar findings. (ref)
But human orthopedic surgeons have known for a long time that x-rays are not a good indication of how much pain their patients are experiencing. Some patient’s knee x-rays look horrible; but the patients reports very little pain. Other times, the x-rays do not look all that bad; but the patients reported severe pain. ( rptref) I do not see why that should be any different with your cat. Veterinarians other than myself have drawn the same conclusion. (ref) In another study of cats in the Netherlands, only 13 out of 100 owners of cats who had x-ray evidence of arthritis reported that their pets were lame. (ref)
So what I mentioned about your observations being a better judge as to whether your cat requires pain medications still goes.
Scientists have never liked subjective response forms and client-based checklists when trying to decide if a medicine actually works – neither do the FDA or EMA . Folks have spent considerable effort trying to devise a more scientific way to measure pain in cats. I am not impressed with the accuracy or usefulness of those tests. It always comes back to the fact that we can’t just ask our feline friends “are you in pain?”. Like herding cats, cats in research setting just aren’t going to give you usable data – short of inflicting on them substantial trauma. There are just too many confounding factors to make these scales of much value. But you can read about some of these attempts here if you wish : (A, B, C, D, E, F) Others have invented machines, sort of pain-O-meters, that claim to assess pain in cats more accurately. (ref) It is next to impossible to decide if a cat withdraws from the stimulus these machines generate due to pain – or just simple annoyance. (ref)
Other confounding (confusing) factors come into play. Some poke and prod at spays incision. That there is pain when poking or jabbing an incision is really no indication that there is pain when not poked. Tests like that are really not valid methods to justify that powerful post-surgical pain control medications are required. I believe that effective activity monitors, used at home, are a more scientific way to judge the effectiveness of pain control medications in your cat, the need to give them and the lowest effective dose. If your cat’s activity does not increase during a 14-day trial with a medicine, the benefit of that medicine or its current dose needs to be reconsidered. There are plenty of activity meters on the market; but most were designed to use GPS technology to locate lost cats. Those do not work well indoors. You will need one that is accelerometer-based. (read here) According to the manufacturer, both the the FitBark and the FitBark 2 (with 6 months battery life) work well for cats (although they don’t market them specifically for cat owners). The manufacturers of the Fitbit Zip, believe their product could be used in cats as well. Products come and go, technology and miniaturization change rapidly, so I could use your feedback on this.
What Medications Are Best For Post-Surgical Pain Relief In My Cat?
I favor medications that numb the surgical site. They have been around a long time. We know a lot about their effectiveness and they rarely produce side effects. (rptref)
If you have been to a dentist, you are acquainted with the Lidocaine/xylocaine used to numb your gums. It is very effective. However its effect soon wears off. In 3-5 hours you can feel your lips and tongue again. Bupivacaine (Marcaine®), a similar drug, lasts for up to 8 hours. It has been used extensively for post-surgical pain relief in humans. (ref1, ref2, ref3) Bupivacaine appears to lessen post-surgical pain in cats as well. (ref) It is an inexpensive drug. Since the government (DEA ) does not consider it as having addiction potential, they do not hassle us veterinarians about administering it as they do with “control schedule ” drugs. As I mentioned earlier, judging the effect of all pain control medications in cats is a challenge. (rptref)
Some veterinarians administer narcotics, buprenorphine or butorphanol, to cats prior to surgery to lessen the chances of after-surgery pain.(ref1, rptref2) Of the two, buprenorphine seems to be the most effective. (ref)
There are veterinarians who will give cats an injection of a NSAID medication prior to surgery. (eg meloxicam/Metacam ®, Robenacoxib/Onisor ®) But there is no solid evidence that these medications help alleviate post surgical pain in cats. NEVER PLUCK ONE OF YOUR SIMILAR HUMAN NSAIDs OR ANY OTHER PAIN RELIEVER FROM YOUR MEDICINE CABINET AND GIVE IT TO YOUR CAT.
No medication for post-surgical pain is as important as good surgical technique, minimal surgical trauma, good pre and post surgical care and getting otherwise healthy cats home as soon as possible. Take the day off. Veterinary hospitals should never house felines and canines in close proximity.
What Medications Are Best For My Cat When Chronic Joint Pain, Arthritis Or Other Long Term Pain Are The Issues?
Here is where veterinarians run into medication challenges due to the unique way that cats process certain drugs. Veterinarians tend to avoid non-steroidal anti-inflammatory drugs because of those potential problems and often suggest nutraceutical glucosamine/chondroitin supplements (like Dasuquin® or Cosequin®) instead.
Glucosamine and chondroitin
Veterinarians really have no solid evidence that these and similar products are helpful. They have no long-term benefit in humans with arthritic pain. (ref1, ref2, ref3), in dogs (ref) or experimental animals. (ref) (Companies marketing these products sponsor their own studies that show them to be beneficial. But I can prove that the earth is flat if I get to choose the study parameters and publish in some half-baked journal) These products are harmless when given to pets or taken as directed. So 3 out of 5 people with joint arthritis pain still elect to take them. (ref)
NSAIDs Non-steroidal Anti-inflammatory Drugs
There are two of these drugs, meloxicam (Metacam ® ) and Robenacoxib (Onisor ®), licensed in the USA for use in cats. (ref) Metacam, as a single post-surgical injection, Onisor tablets for a maximum of 3 days.
The product warning that long-term use can be dangerous to cats is based on the slow rate that cats eliminate these drugs and other NSAIDs from their bodies (a lower ability for hepatic glucuronidation than humans or dogs). (ref) Yet, many veterinarians feel that one can get around that problem by increasing the space of time between doses, and that there are times when chronic pain justifies the possible risks of long term NSAID administration. (ref) Both meloxicam and carprofen (Rimadyl®) are licensed for longer-term use in cats in countries other than the USA. (ref)
With any of these NSAIDs, in any species, the correct long-term dose is always the lowest one that gives relief. For safety, relief needs to be a beneficial compromise of improved motility, not an attempt to completely turn back Aging’s clock. Even then, one must always be on the lookout for digestive tract issues, and monitor your cat’s liver and kidney tests as long as the pet receives these medications. Kidney issues are a particular worry to me because of the kidney effects of NSAID across all species. (ref) Cats are particularly susceptible to kidney issues (CKD ) later in life.
Elderly cats – even those not receiving medications – are particularly susceptible to loss of kidney function. Veterinarians do not know why that is. So be sure that your cats on these medications drink plenty of liquids and stay well hydrated. The best way to do that is to feed them very moist diets.
In chubby and overweight cats, it is safest to calculate its NSAID dose based on the weight that a non-obese cat of its stature would have (ie. give the cat less). Cat too fat?
There is probably more information on the long-term use of meloxicam (Metacam®; Boehringer Ingelheim) in cats than the other NSAID options. Although the product insert says to give the oral feline preparation at 0.05mg/kg of body weight for a maximum of four days, there are vets who give it longer at one-half that dose. There are no long-term studies that I know of that measured the drug’s effects on the cat’s kidneys or liver. In one group of cats given meloxicam for 5 days, kidney function did not appear to be impaired. (ref) However, another 21 day study of meloxicam in cats (@ 0.035 mg/kg/day) hinted at “adverse renal (kidney) effects” which these veterinarians thought might be related to dehydration caused by vomiting induced by the drug. (ref) Meloxicam is also formulated as an oral spray for dogs (OroCAM™). Although it is not approved for cats, one study found it as effective in cats as orally administered meloxicam. (They did not study what the effects of the drug might have on the kidneys or other organs of these cats) (ref)
Robenacoxib/ Onisor is also an NSAID. It is marketed in tablet and injectable form by Elanco, a division of Eli Lilly. In a 2016 study (that Elanco paid for), their authors found no indications of damage to the intestinal tract, kidneys or liver of cats receiving the drug for one month. (ref) Others have pointed out that: “the study was in a relatively small number of cats and may not have accurately reflected the likelihood of rare but serious side effects and that further studies in a larger group of cats ought to be performed”. (DVM360 9/26/16)
Neither Oisor nor Metacam should be given when corticosteroids (eg prednisolone, prednisone, etc.) are given. Some corticosteroids, such as methylprednisolone acetate (“Depo”) take several weeks to leave your cat’s system. If you elect to give this medication to your cat, as with Metacam, be sure it stays well hydrated while on the medication.
This is one of the latest NSAIDs to reach the veterinary market. You can read an article of mine specifically on Galliprant here. Galliprant may be less inclined to cause gastrointestinal or kidney issues (because it is a selective prostaglandin Cox-2 EP4 inhibitor). (ref)
Galliprant is currently approved for dogs. Folks using it in their dog, who have written to me through 2017, seem quite pleased with the medication. (ref) As I write this article in 2018, Galliprant is not approved for use in cats. But a 2016 international study gave a single dose of grapiprant to six cats and observed them over the next three days. They reported “no behavioral or health abnormalities during the three day period”. ( read here )
The makers of Galliprant (Aratana) are aware that there would be a market for their drug to control chronic inflammatory pain in cats. In 2014, they submitted a document to the US Securities & Exchange Commission regarding a pilot studies on the use of Galliprant (=AT-001) in cats. That submission appeared to indicate they had faced liver issues in some of the cats and were working to see if a way could be found around that.
Tramadol is a narcotic – somewhat similar to codeine. It has been given to cats to lessen post-surgical pain. (ref ) Tramadol is quite bitter. But some cats will accept it when flavoring compounds are added to it. Tramadol is quite effective against moderate pain in humans. There is little data on the effects of its long-term use in cats. (rptref) One 2008 study did not find it particularly effective in decreasing pain in cats at the dose at which it was used. (ref) Results of tramadol’s effectiveness in dogs are modest as well. (ref) That might have been expected since, in humans, Tramadol seems most effective in controlling neuropathic pain and considerably less so when arthritis or joint damage is the cause. (ref1, ref2) Never-the-less, it might be a good choice for a 14-day trial of effectiveness in your cat with confirmed long-term pain that results in mobility issues. (ref1, ref2) Be careful with dosage as the drug can produce side effects (ref1, ref2) that include mood changes. (ref1, ref2) Dosages might need to be adjusted down in cats with liver or kidney issues. (ref1, ref2)
Other Prescription Narcotics
A wide variety of other prescription narcotics are suggested for use in cats. The only one I have experience with is the use of fentanyl patches in cats with terminal cancer. But you can read about the use of other prescription narcotics in cats here.
Gabapentin is a drug approved to treat neuropathic pain in humans. That is, pain that occurs due to things like diabetes (diabetic neuropathy) or subsequent to herpes. In those cases, it is said to help about 15% of the people who use it. Some physicians dispense it for chronic back pain. But its effectiveness there is in doubt as well. (ref) It is also used by some veterinarians “off-label” to treat chronic pain in cats. It has been suggested for acute pain as well. (ref) There is no verifiable data as to whether gabapentin is helpful in the treatment of pain in cats.
Amitriptyline is an antidepressant (tricyclic antidepressant) that is used to treat fibromyalgia, migraines and herpes-related pain in humans. There is moderately strong evidence that it is helpful in reducing pain in about 20% of the people who take it. (ref) It has been used for a long time in cats – usually to treat behavioral problems like peeing outside their litter box, with mixed results. There are veterinarians who use and suggest it for chronic pain in cats. There is no scientific evidence one way or the other as to its effectiveness.
Anti Nerve Growth Factor frunevetmab
I wrote an article on this pain control medication earlier in 2017. It has not yet been approved by the FDA. You can read that article here. This drug is a monoclonal antibody. Monoclonal antibody drugs are species specific; that is, they are engineered to work in only one species. Most have been humanized (like Humira® ) because that is where the big potential market is. But a new veterinary pharmaceutical company, Nexvet, that is developing dog and cat drugs, has developed the ability to make any of the newer human MaBs pet friendly. They can “dogicize” a drug or “caticize” a drug. They are working on one that might alleviate chronic pain in dogs. If successful, one for chronic pain in cats might be right behind. Nexvet was recently purchased by Zoetis, the former veterinary division of Pfizer. Their forward looking press statement calls frunevetmab a potential break through in the treatment of chronic feline pain since “Feline treatments for pain are limited, and frunevetmab could open up a new opportunity in feline pain that is underserved today”. I do not know the timetable for its release or its current use among veterinary pain experts. But you can read the 2016 press release on their development progress for its use in cats here.
Are There Non- Drug Alternatives To Dealing With Pain In My Cat?
Warmth is generally beneficial to the chronic pain of arthritis and joint inflammation. Warmth also speeds the recovery from acute pain. My favorite source of heat for dogs and cats are rigid pet or livestock-designed heating mats with soft covers and a maximum temperature control of no more than 105F. My favorites are similar to these. (ref)
Be sure your cat has the capacity to leave the mat if it becomes too warm. Pain control medications, severe arthritis or joint injuries can make cats hesitant or unable to do so. Hot water bottles are equally as effective if the cat accepts them. But they are quite labor intensive.
If your cat is overweight, begin it on a weight reduction diet. Buy a scale, keep a diary. Weight loss should be gradual, no crash diets please. Its not only that excess weight is hard on the joints and spine. Fat is also pro-inflammatory. (ref)
Have water sources available at many locations. Cats can easily become dehydrated and dehydration is thought to increase the chances of bad reactions to NSAID and other drugs as well as put extra stress on the cat’s kidneys.
Buy a comfortable and soft cat bed with very low sides placed in a draft-free location. If your cat prefers an igloo bed, modify it so that it does not have to step up to enter. Add ramps to make favorite resting places more accessible.
Mind diversions and distractions of all kinds might take your cat’s mind off of its focus on pain. We know that diversions and mindfulness seem to help humans divert their thought from pain. There is nothing I know of published that seeks to tell if these same sort of diversions might ease long-term pain in cats but there is certainly no harm in trying. Open your drapes for window views. If your cat can no longer jump to the window ledge, construct a ramp. Cat toys if your cat shows interest in them. Puzzle feeders and small snacks throughout the day. Catnip and cat grass if they please your cat. Lap time and stroking massage. Diversion ideas are only limited by your imagination.
Cats are independent creatures with less “aim to please” than a dog. They would make terrible waiters. They do it their way. So please do not be upset with your cat if it does not say thank you or if it doesn’t cooperate in using the suggestions I have provided.
Omega 3 Supplements PUFAs
Omega-3 fatty acid supplements are thought by many to reduce inflammation. (ref) In humans, there are lots of positive studies. (ref1, ref2, ref3) But I cannot tell you for sure if they will be helpful to your cat. Besides capsules, fresh cooked herring, salmon and mackerel are excellent sources of omega-3s. You will need to offer them to your cat in moderate amounts and see if they appear to make your cat more motile. Don’t overdo the use of these products. (ref)
Complimentary and Alternative Medicine
When you read my articles, you are reading about science-based, evidenced-based treatments for your pet. Alternative and complimentary based medicine are an alternative to science-based, evidence-based medicine. I don’t believe in treatments when I cannot see evidence that they work. That’s just my mindset. But that doesn’t mean you should not try those things on your cat just because I do not believe in them. Most are harmless; and new ones pop up every day. They include acupuncture, laser therapy, homeopathy, holistic therapies, rejuvenating stem cell treatments, myofascial trigger point therapy, Reiki, universal energy transfer, channeling, laying on of hands, energy therapy and applied kinesiology. I have no faith in chiropractic either – other than when it is used to avoid or delay powerful medications and surgical procedures whose risks outweigh their benefits. When humans are in pain, placebos like these can have powerful positive effects. ( read here) I am not sure if that applies to cats. But at the least, techniques like these that provide nothing tangible can be considerably better for your pet than providing something tangible – when it is the wrong something.
Might Veterinarians Be Getting It Wrong When It Comes To Pain In Cats?
I have always anthropomorphized my cats. I talk to them frequently. I praise and reward them for good behavior. I’m happy when they’re content. I’m worried and fret when I think they hurt. I’m disconcerted when I think they are ignoring my pleas – Obstinate rebellious teenagers! I give them gifts at Christmas. I verbally chastise them when they are naughty. It is common for cat owners and caring veterinarians to be like that. They are my furry children. When I poke fun at “pet parents” I poke fun at myself. How much pain cats actually experience is essentially unknowable. We base our opinions on how we would react and the pain we would experience in a similar situation.
I mentioned earlier the frustration of veterinarians that they cannot produce similar reactions to pain-causing stimuli in cats that physicians see in humans – or even dogs – and how that has delayed the development of drugs. Vexed with that fact, their tendency is to explain it away by stating that cats “hide” “mask”, “conceal” or “disguise” their pain. The inference is that cats find it undignified or embarrassing to show symptoms of pain. There is absolutely no scientific data to support that. But there is considerable scientific evidence that some animals perceive less pain or perceive pain impulses in different ways than we do. It involves species differences in the pathways that potential pain signals follow on their travel to the brain and the chemicals that take part in that process. There is also considerable evidence that under identical circumstances, one individual will experience more pain than another. (ref)
We all compartmentalize our thoughts – as if they were in a series of rooms. Your interpretation of events and the decisions you make depend a lot on which room you are in at the time. When you move from the Walt Disney/pet parent room to the objective scientist’s room, it is quite apparent that there is no evidence whatsoever that cats attempt to conceal or hide their feeling about anything.
The brain can see and hear what it wants to see and hear – like the crashing of pylons on a video with no sound track.
If you don’t hear it, you think there was one, because in similar situations you have seen in the past, there was one. Never mind that towers don’t jump rope. In interpreting current situations, your brain relies as much on memory of similar events you experienced in the past, as it does on what you see or what you hear in the present.
A better explanation than concealment is that Nature intended cats to perceive many things, including potential pain signals, when they reach the brain, in ways quite different from us humans. There is plenty of data to support that. Although no one knows the architecture and dynamics of pain sensation in cats, we do know that in humans and laboratory animals the feeling of pain involves a very complicated system of pathways that differ significantly between species based on their genetics. It differs between individuals too, due to differing architecture and messenger chemicals at many points – before the potential pain signal reaches the brain and after it arrives there. (ref) Pain perception seems more profound in species that have strong social interactions than those that do not. (ref1, ref2, ref3)
At its most basic level, the feeling of pain depends on how pain messages flow through sodium channels (eg Nav1.9 Channels). (ref) How those channels function and how much pain is perceived differ between species. (ref1, ref2, ref3) Some differences in the amount of pain perceived are profound. For example, humans perceive thermal grills as painful but cats do not. (ref) Mice and humans differ significantly in their pain perception as well. (rptref)
Still, many veterinary pain specialists continue to propose that cats experience the same degree of pain that us humans would under the same circumstances. But in the only cat study I know of – one that compared a certain form of pain sensation (to cold) between humans and cats – cats were found to be considerably less sensitive. (rptref)
My Take-home Point:
When it comes to chronic and acute pain, there are significant differences in intensity between cats and humans. It’s most likely that cats aren’t hiding their pain at all, they’re just not experience as much of it as we would under the same circumstances. God’s blessing to felines