Twenty years ago, veterinarians' approaches to treating osteoarthritis pain in companion animals were, for lack of a better word, rudimentary.
“We had so few tools and even less understanding of pain pathophysiology,” said Robin Downing, DVM, of The Downing Center for Animal Pain Management in Windsor, Colo. “We were still locked into thinking that dogs and cats experienced pain differently from humans.”
Aspirin was the drug of choice back then, said Dr. Downing, as well as “‘bute' [phenylbutazone] with the occasional joint corticosteroid injection,” said Michael C. Petty, DVM, Dipl. American Academy of Pain Management, owner of the Animal Pain Center of Arbor Pointe Veterinary Hospital in Canton, Mich.
Both practitioners pinpoint a significant breakthrough in veterinary medicine that began to shift veterinary practitioners' approaches to managing osteoarthritis pain.
“When Pfizer Animal Health came out with Rimadyl, it changed the entire game,” said Dr. Petty, who is also the president of the International Veterinary Academy of Pain Management.
“Not only did we have an amazing new product to treat OA, Pfizer did a great job in teaching veterinarians how to recognize the signs of OA in dogs.”
The 1997 launch of the first non-steroidal anti-inflammatory drug for dogs was the most important tipping point for helping the veterinary profession take chronic pet pain seriously, said Downing.
“For the first time, we had a tool for chronic pain management that had been developed specifically for use in dogs,” she said.
Rick Wall, DVM, CCPR, Dipl. American Academy of Pain Management, is the owner of Animal Clinics of The Woodlands and the Center for Veterinary Pain Management and Rehabilitation in The Woodlands, Texas. He said that since the introduction of NSAIDs for animals, practitioners' understanding of pain in general has been evoling.
“We started thinking about the management of pain in my practice about 17 or 18 years ago, starting with acute pain, the perioperative type, then it evolved into the recognition of chronic pain,” Dr. Wall said. “Then groups like the International Academy of Veterinary Pain Management and different people around the country started to discuss pain.”
He said the last 10 years have seen the most significant growth in understanding pain in veterinary medicine.
“It has been an ongoing evolution since then, but that was the moment that set the transformative change in motion.”
Since then, said Downing, practitioners' knowledge about chronic osteoarthritis pain has expanded.
“And the more we learn, the deeper [grows] our understanding of the importance of taking care of these patients by relieving them of their unnecessary and unrelenting suffering.”
In 2009, the University of Missouri reported that, “Veterinarians predict that 20 percent of middle-age dogs and 90 percent of older dogs have osteoarthritis in one or more joints.”
As a greater number of patients suffering from OA pain come through veterinary practices, the veterinary community is continuing to grow in management techniques.
Bob Harman, DVM, MPVM, founder and CEO of Vet-Stem Inc. of Poway, Calif., which provides regenerative stem-cell therapy, said that the veterinary industry has made great strides in educating practitioners and pet owners about observation and diagnosis of osteoarthritis.
Still, the idea that companion animals suffer from osteoarthritis pain may not be common to pet owners.
“The change in pain management from the owner's perspective has not kept up with the veterinary advances in pain management,” Petty said. “Veterinarians have to do a much better job in educating pet owners in the modalities that are out there.”
Downing said that her typical client doesn't know much about osteoarthritis in pets and often mistakes the signs of OA for the pet simply aging.
“They do not recognize the lost activities of daily living,” Downing said. “They do not realize that decreased stamina during walks or play is not normal, and is generally a reflection that the dog is painful. They do not understand that when the cat no longer jumps up onto the windowsill to enjoy watching the birds in the yard, it means that the cat can't jump, not that the birds have become boring.”
Clients who typically come to Wall's referral clinic often recognize that there's a problem with their pet, but they don't necessarily associate it with osteoarthritis pain. But in his general practice, patients' pain is usually noticed during an examination and by his staff asking the right questions, Wall said.
“They do not realize that decreased stamina during walks or play is not normal, and is generally a reflection that the dog is painful,” Downing said.
Greater Attention to Signs
Because few pet owners are presenting their pets for examination for possible osteoarthritis pain, practitioners should look for it in every patient, Petty and Downing say.
“We actively look for it,” Petty said, “starting with observations by support staff, technicians and, of course, myself. This includes giving a pain survey for all patients considered geriatric.”
Downing stressed that the “Pain Management Guidelines for Dogs and Cats” released by the American Animal Hospital Association and the American Association of Feline Practitioners in 2007 recommends that veterinary healthcare teams evaluate every patient every time for pain. (The pain guidelines may be found online at www.aahanet.org/publicdocuments/painmanagementguidelines.pdf.)
“That really means every patient every single time they come to the practice,” Downing said. “That is now a part of the AAHA standards for accreditation.”
Because her practice closely adheres to the guidelines, “We identify patients who are painful, generally long before their owners would notice a problem,” Downing said. But even owners who have overlooked their animals' potential osteoarthritis pain, Downing finds, want to relieve their pets' pain right away.
Dogs Versus Cats
Although both cats and dogs with osteoarthritis share the common trait of inactivity, more dogs than cats are diagnosed with OA for a few reasons, including that cat owners sometimes need convincing that their cats are actually in pain.
“Like most practitioners, I see more dogs than cats,” Petty said. “People are less likely to report the signs of chronic pain in cats, until they quit using the litter box or quit jumping, so that when a cat is brought to me it is a much harder job to convince the owners that their cats are in pain.”
“For cats, decreased grooming behavior is a big sign that they are painful,” she said. “Of course, our physical examination is the key to finding OA pain in cats. We also rely on the history delivered by cat owners to help us.”
Multimodal Treatment Trends
NSAIDs are still the gold standard pharmaceutical for treating OA pain, Petty said, but he incorporates other techniques, too.
“I like to utilize sensible exercise and rehab for strengthening, acupuncture for pain control, close attention to weight control including OA diets and the use of other pharmaceuticals for pain control,” Petty said. “And one of my favorite treatments is to treat the secondary myofascial pain with a technique called dry needling.”
Petty's feline patients also benefit from Adequan injections, as well as acupuncture, he said.
Complementary veterinary practices are also in Downing's arsenal.
“Medical acupuncture, medical massage, all the various physical therapy/rehabilitation techniques, myofascial trigger point release, chiropractic adjustment are all in common usage with good results when applied to the appropriate patients.”
“There are about seven areas of multi-modal management of OA pain and not every patient is going to need all of them,” Wall said.
Using them in various combinations will yield the greatest success, he said: weight loss; exercise; pharmaceuticals, including disease modifying osteoarthritic drugs such as Adequan; adjunct pharmaceuticals, most of which don't have FDA approval for use in pets but are widely accepted in veterinary medicine; physical medicine modalities such as therapeutic laser therapy (Wall has two Class IIIs and one Class IV machine in his practices), extracorporeal shock wave, trigger-point therapy and acupuncture; rehabilitation; and nutraceuticals.
At the Downing Center normalizing a pet's weight is also step No. 1 in OA pain management for dogs and cats. “Without weight loss for overweight pets, pain management will be a tepid success at best,” Downing said.
She then breaks the pain cycle with NSAIDs and other medications, including gabapentin. “We then initiate physical medicine modalities, and we may initiate therapeutic exercise as well,” she said.
For certain patients, another approach for not only treating osteoarthritis pain but possibly reversing the damage seen with the disease is regenerative stem-cell therapy.
“Practitioners have choices of anti-inflammatory drugs, pain drugs, laser and now stem-cell therapy as new tools,” said Vet-Stem's Harman.
“Regenerative medicine provides a wholly new modality by providing the ability to reverse the damage seen in OA. The chronic degradation and inflammation can be halted and there is published peer-reviewed evidence of real regeneration such as cartilage and meniscus injury (Dragoo 2007, Toghraie 2011, Sato 2012).
“Use of stem cells also helps spare the use of drugs that might be damaging when used long term.”
Challenges Moving Forward
Harman said that the greatest challenge facing veterinarians managing patients' osteoarthritis pain is education—of both veterinarians and pet owners.
“The field is growing in leaps in bounds,” Petty said.
“Even as a pain practitioner, I have to read and review all the time just to keep up with current trends and developments and essentially separate the wheat from the chaff. This is one of the reasons I joined the International Veterinary Academy of Pain Management.”
“The biggest challenge is simply identifying patients who are painful,” Downing said. “Unfortunately, most veterinary practices still do not include a pain assessment as a part of every single examination. You can't treat what you don't identify.”
Downing also said that many still believe that NSAIDs are the only tool for treating OA patients in pain.
“Almost every painful patient I see is already on an NSAID, and yet has a palpation pain score of six to eight out of 10 (0 = no pain, 10 = passing a kidney stone). Chronic pain is maladaptive pain, and maladaptive pain will not be resolved by an NSAID alone.”