Recently updated guidelines seek to improve pain management in small animals
October 14, 2015
This article is more than 3 years old
The Buzeks’ dogs, Wrigley and George, often roughhouse and roam free in the family’s large, open yard.
The two have been friends since they were puppies. Wrigley, a 10-year-old Golden Retriever, is calm and collected. George, a 9-year-old Weimaraner, is a hefty 90-pounder who is always ready to play.
One evening, Karen Buzek found Wrigley hobbling up the stairs on three legs. She presumed George must have played too hard with Wrigley.
Because Wrigley continued to limp, the family sought veterinary attention. And that is when they learned from their regular veterinarian that Wrigley had torn his cranial cruciate ligament and would need surgery.
Wrigley was soon scheduled to undergo a tibial plateau leveling osteotomy at the Veterinary Specialty Center in Buffalo Grove, Illinois.
With surgery—as with any illness or injury—managing pain should be an essential conversation between pet owners and their veterinarian. Earlier this year, the American Animal Hospital Association and American Association of Feline Practitioners, working together, released new guidelines regarding pain management in small animals. The World Small Animal Veterinary Association released its own guidelines last year. These two documents aim to create consistency and advance animal welfare by promoting effective pain management for small animals.
Importance of pain management
The ethics of animal treatment and veterinary care have changed dramatically over the past several decades. Managing pain and preserving quality of life in small animals are now considered just as important as healing illnesses and injuries.
“The tide is changing, but we desperately need to enthuse and train the next generation of clinical scientists who will dedicate their careers to understanding how to measure and alleviate pain in companion animals,” said Dr. B. Duncan Lascelles, one of seven co-authors of the updated WSAVA Guidelines for Recognition, Assessment, and Treatment of Pain. He is a professor of surgery and pain management at the North Carolina State University College of Veterinary Medicine, where he heads the Comparative Pain Research Program.
Quality of life is diminished when pain impedes everyday life and function.
“Pain may not kill you, but it can kill your personality. It kills our pets’ personalities,” Dr. Lascelles said. “It’s essentially why owners present their pets to veterinarians.”
The American College of Veterinary Anesthesia and Analgesia, an organization deeply focused on pain and pain management, has defined pain as “a complex phenomenon involving pathophysiological and psychological components that are frequently difficult to recognize and interpret in animals.” Pain is categorized as acute or chronic. Each has distinct characteristics, although acute pain can occasionally turn into chronic pain if it is not recognized and treated appropriately.
Dr. Lascelles said the biggest reasons for underrecognizing both types of pain, especially chronic, are lack of understanding of how to measure pain, the limited amount of clinical research—and, therefore, evidence-based guidelines—on pain management in small animals, and failure to prioritize pain in treatment plans.
Recognizing pain in small animals
Dog and cat owners tend to have difficulties determining whether their pets are in pain or are uncomfortable. For this reason, both the AAHA/AAFP Pain Management Guidelines for Dogs and Cats and the WSAVA guidelines suggest that veterinarians discuss with owners how the pets are feeling and whether they have observed any signs of acute or chronic pain.
According to the AAHA/AAFP guidelines, acute pain has nociceptive and inflammatory components. In small animals, pain from illness, injury, and even surgery manifests as changes in behavior.
Dr. Karen Faunt, the vice president of medical quality advancement for Banfield Pet Hospital, said one effective evaluation method available to Banfield employees is pain scales. Banfield’s revised 2010 anesthesia book includes discussion of incorporating pain management into treatment plans. Dr. Faunt said putting the emphasis on determining pain levels on the basis of the animal’s stance and reactions to caregivers has been an effective teaching tool for veterinarians and veterinary technicians to use with clients.
Several scoring systems have been developed to help veterinarians assess the severity of acute pain in dogs and cats by examining posture, movement, social interactions, and response to palpation, including the Glasgow Composite Measure Pain Scale for dogs and the Multidimensional Composite Pain Scale for postoperative pain in cats. Assigning a numerical score or description to pain severity helps not only in the recognition of pain but also in the assessment of changes in pain over time or in response to treatment.
As with acute pain, chronic pain—also known as maladaptive pain—can be accompanied by characteristic physical signs. But determining the underlying cause of chronic pain and identifying changes over time can be much more difficult. Still, there are scoring systems for evaluating chronic pain, such as the Canine Brief Pain Inventory, developed by the University of Pennsylvania. This owner-completed questionnaire is designed to measure the severity of chronic pain in dogs.
Veterinarians and pet owners play an important role in behavior assessment, said Dr. Ilona Rodan, another co-author of the updated AAHA/AAFP guidelines and, until recently, the owner of the Cat Care Clinic in Madison, Wisconsin, where she continues to practice. Changes from normal behavior can be indicators of chronic pain, making patient history critical.
“We want owners to report changes in behavior, even if they are subtle,” Dr. Rodan said. “For example, if a cat was outgoing with the family, but now it’s often hiding in the closet, that’s a sign, and we need to emphasize to cat owners that these changes often signify pain, and a veterinary appointment is essential to diagnose and treat the underlying problem.”
Dr. Rodan suggests owners keep journals and photos to indicate what their pet enjoyed at peak health.
“When you’re looking at your pet day to day, it’s hard to recognize signs,” she said. “I recommend a picture a year, or at least every few years, because you’re going to pick things up that would otherwise not be noticeable. It can be an important evaluation tool over the long term.”
A recurring topic in the updated AAHA/AAFP and WSAVA pain management guidelines is pain associated with degenerative joint disease in small animals. Dr. Lascelles said most of the clinical research on DJD has been in dogs.
“You might call that low-hanging fruit,” he said, referring to the research into arthritis pain in dogs. “It’s one of the easiest aspects of pain measurement in one of the easier species to measure in, but it’s a great place to start.” However, NC State has pioneered research into understanding chronic pain in cats and has recently produced the first assessment tool for it.
Dr. Rodan said she helped initiate the conversation on including a discussion of DJD in the AAHA/AAFP guidelines to educate veterinarians and owners that it is a common issue for both cats and dogs.
“It’s been only in the past five or six years that you find journal articles about DJD in cats,” Dr. Rodan said. “We knew some cats had arthritis in the past, but the increase in studies on feline DJD and awareness of the high incidence of the condition in cats has really come to a head now.”
Creating effective pain management plans
In clinical practice, recognizing and treating pain in small animals should not be considered solely a task for the practice veterinarians but a team effort. Planning is essential to helping mitigate the degree of pain.
The AAHA/AAFP guidelines suggest using the PLATTER approach—PLan, Anticipate, TreaT, Evaluate, Return (see Figure 1 below)—for pain management.
Adopting this approach during routine visits as well as appointments focused on a specific illness or injury is recommended to aid in the recognition of both acute and chronic pain.
Dr. Alicia Karas, a veterinary anesthesiologist at the Cummings Veterinary Medical Center at Tufts University in North Grafton, Massachusetts, said the guidelines are particularly helpful in providing multiple solutions to the problem of acute and chronic pain.
“The guidelines aren’t a prescribed way of doing things; they are suggestions, and they give options,” she said. “There’s not one way to do any of the pain management. That’s what is so exciting about having the guidelines.”
For treatment in her practice, Dr. Karas said she often combines drug therapies with nondrug therapies to provide long-duration relief, and she makes sure to create plans that engage her clients in managing and treating pain in their pets.
Drug and nondrug therapies for pain
Opioids and local anesthetics are commonly used to treat pain in animals during the preoperative and intraoperative periods. The WSAVA guidelines state it is important the two be used together in an aggressive, pre-emptive way to alleviate pain and minimize the use of medications after surgery.
Nonsteroidal anti-inflammatory drugs are also useful in the perioperative period but may occasionally result in complications when combined with other drugs in small animals, according to the WSAVA guidelines. They are excellent, however, for mild-to-moderate acute and postsurgical pain.
Dr. Rodan said many veterinarians are hesitant to use NSAIDs long term in cats because of the potential for gastrointestinal and renal adverse effects, but the AAHA/AAFP guidelines provide important information on how to use these drugs safely.
She said, “These guidelines and studies are increasing the awareness that NSAIDs are the mainstay of treatment of DJD in both cats and dogs.”
Preoperatively, the guidelines suggest using alpha-2 adrenoceptor agonists such as dexmedetomidine as effective sedative options.
Dr. Faunt said, “Premeds for surgery serve many purposes, and that’s why you usually have a sedative along with the pain drug as well.”
Adjunctive drugs such as ketamine, amantadine, or gabapentin can also be incorporated into pain management protocols to offer additional relief for maladaptive pain, according to the WSAVA guidelines.
Dr. Lascelles said there might be more that veterinarians can do with these types of adjunctive medications, but further clinical research needs to be done.
For instance, ketamine is known to be an effective analgesic, can be used in conjunction with opioids and NSAIDs in the perioperative period, and can improve appetite and result in lower pain scores. The potential for humans to abuse ketamine, however, means that the drug is less available for animals in need.
“We began to realize (ketamine) had an amazing beneficial effect not just in pain but to modify disease states,” Dr. Karas said. The American College of Veterinary Anesthesia and Analgesia, the International Veterinary Academy of Pain Management, and other groups have challenged the United Nations Commission on Narcotic Drugs not to restrict the availability of ketamine by reclassifying it under the International Convention of Psychotropic Substances. Under the U.S. system, ketamine is classified as a schedule III drug.
In addition to drug therapies, a variety of nondrug therapies have been advocated for management of pain in small animals. According to Dr. Lascelles, good alternatives to drug therapies would be to focus on preventive as well as postoperative care.
“Unfortunately, in many parts of the world, our companion animals are looking more like ourselves and acting more like ourselves,” he said. “They’re becoming bigger, fatter, and doing less exercise. It’s important to manage the pain associated with painful diseases such as osteoarthritis but also to limit the disease through nutrition, exercise, and so on.”
Multimodal therapy allows reduction in doses of each medication, which leads to less chance of adverse effects and offers more opportunities for alternative therapies. Alternatives such as rehabilitation and cryotherapy have also been shown to be effective in some instances, and modifying the animal’s environment by providing pet steps or ramps allows the animal to perform its normal routines.
Dr. Rodan advises her clients to not only work on the health of the animal but also to create a safe environment.
“The home environment becomes even more important with chronic pain,” she said. “For example, if the cat sleeps on the bed with the owner, put in a ramp or steps. If the cat cannot sit comfortably to eat, raise food and water dishes a few inches so that the cat can eat comfortably. These measures ensure that cats can continue to be important family members and perform normal cat behaviors, despite their condition.”
Wrigley’s pain management plan
In Wrigley’s case, a lot of preparation was needed to soothe the pain associated with his CCL tear and subsequent tibial plateau leveling osteotomy.
Dr. Jusmeen Sarkar, Wrigley’s anesthesiologist at the Veterinary Specialty Center, said her plan for Wrigley would be multimodal, with consistent follow-ups for reassessment and substantial home rehabilitation.
Buzek said, “He’s supposed to have a gradual return to full activity by nine or 10 weeks. ... (The rehab handouts) tell me to move his back legs in a bicycle motion in slow repetitions, go on slow leash walks, and massage him a couple of times a day.”
Wrigley’s regular veterinarian would perform routine follow-up examinations to see how he was recovering and whether his personality and normal behavior were returning. The specialty center follows the PLATTER method of assessment, Dr. Sarkar said, and many other clinics are beginning to follow it as well.
It is an extensive, thoughtful process, Dr. Sarkar said. “But when patients wake up more comfortable, they require a shorter amount of time on medications. They heal faster, they want to move more. The goal is to have them return to normal function as soon as possible.”
Rashmi Shivni is a fourth-year journalism major at Columbia College in Chicago and was the 2015 summer intern with JAVMA News.
Chronic pain in dogs and cats can manifest as changes in any of the following characteristics:
Mobility and energy level.
Temperament and mood (e.g., dull, alert, or anxious).
Eating and drinking.
Rest and comfort level.
Time spent grooming (especially in cats).
Pain management plan for Wrigley’s tibial plateau leveling osteotomy
Dexmedetomidine (adrenoceptor agonist).
Propofol (induction of anesthesia).
Midazolam (sedation and amnesia).
Epidural of preservative-free morphine (opiate-type pain reliever) and preservative-free bupivacaine (local anesthetic).
Isoflurane (maintenance of anesthesia).
Postoperative (in hospital for 24 to 36 hours)
Hydromorphone intravenously every
six to eight hours.
Postoperative (at home)
Rehabilitation (range-of-motion exercises).
Nonsteroidal anti-inflammatory drugs and oral hydromorphone for up to five days.
Gabapentin if needed for chronic pain in conjunction with other pain relievers.