Assessing and treating pain in cats
HALIFAX, NS –Studies have shown that cats receive analgesia less frequently than dogs, and in cats it is often withheld for fear of an adverse reaction. While presenting at the Atlantic Provinces Veterinary Conference, Elizabeth O'Brien, DVM, DABVP (Feline), explained that the key to recognizing pain in a cat is to recognize a change in behaviour, and that requires recognizing what the cat’s normal behaviour is in the first place, both in the home and in the clinic. While cat owners know that cats get many diseases, pain from diseases and degenerative joint disease (DJD) is overlooked. Therefore, it is up to veterinarians to educate veterinary teams and clients about acute and chronic pain in cats.
Signs of inadequate pain management
In addition to being a welfare issue, inadequate pain management is associated with many detrimental effects in cats including inappetance, cachexia, delayed wound healing, altered mentation, impaired immune function, urine and fecal retention, self-mutilation of painful sites, and prolonged recovery from a procedure or illness.
Dr. O’Brien said that physiologic parameters, such as heart rate, respiratory rate, blood pressure, and rectal temperature are poor indicators of pain in cats. Some indicators of pain in a hospitalized cat include lack of appetite and interaction. Sometimes cats hide in the back of the cage, and those unable to sleep or rest may seem to “sleep” with their eyes open. She says that her team makes note of the natural behaviour of each patient; change in the individual cat’s behaviour cannot be over-emphasized. In addition, evaluation of body posture, facial expression, and response to handling, including palpation of surgical sites, is key. However, sometimes critically ill patients may not be able to show behaviours associated with pain and yet may require management for severe pain.
Proper pain management in cats
Dr. O’Brien stressed that pain requires a multimodal approach using different classes of analgesics, including the routine use of local anaesthetic nerve blocks for surgical and some medical procedures. Evaluations of hospitalized patients should be carried out repeatedly to monitor analgesia efficacy and to determine if a change in the treatment plan is required. A return to normal behaviour is a sign of good pain control.
Chronic pain/arthritis/degenerative joint disease (DJD)
The vast majority of cats 12 years of age and older will show radiographic evidence of arthritis, and more than half of cats aged six years of age or older have osteoarthritis in at least one joint. And yet, noted Dr. O’Brien, very few cats are routinely diagnosed with osteoarthritis. Since major cartilage pathology can be present in the absence of any bony change, radiographic identification of DJD in the cat can be problematic.
Recognizing arthritis in cats
A questionnaire and history using a checklist about the cat's behaviour is invaluable and should be included with all veterinary visits, ideally sent to the client before the appointment. Topics include the ability to jump, agility when jumping, change in activity, change in sleeping location (fewer locations, or the same spot all the time), inappropriate defecation/urination, change in socialization, decreased activity, decreased hunting or play behaviour, lower scratch marks on scratching posts, and poor hair condition (result of lack of grooming).
Dr. O’Brien stressed the importance of having the cat client recognize “normal behaviour” before problems develop. She suggested having clients write a letter about their young adult cat’s behaviour, which should be reviewed annually. It should include places the cat sleeps, amount they hunt, social behaviour, jumping ability, scratching locations, the order of arrival at meal time, and play time. Any gradual change in behaviour that may otherwise get overlooked by the client would then be noted. Dr. O’Brien stressed that client awareness and education is key for early disease detection and the recognition of arthritis and pain.
Treatment of arthritic pain
If the cat is otherwise healthy with normal renal values, Dr. O’Brien recommended using a 5-day trial of an NSAID as a tool for diagnosing arthritis. Often the cat will show a visible and dramatic improvement. The need of long term analgesia is readily apparent to the cat owner and client compliance is then excellent.
NSAIDs
Dr. O’Brien recommended using NSAIDs for chronic pain at the lowest daily dose possible. For the treatment of musculoskeletal pain, NSAIDS can be used on-label for a short period of time. “At our practice, we use them off-label for an extended length of time (often for life) at the lowest daily dose possible as long as the kidney function is not IRIS Stage 3 or 4 and the cat is not on corticosteroids. We have clients sign a consent form that we are using this product ‘off label’.”
Gabapentin
Gabapentin is used frequently in addition to NSAIDs, in cats that require multimodal treatment with neuromuscular pain. It is also used cats for cats that are concurrently on a corticosteroid or cats with pronounced renal disease, in which case an NSAID would be contraindicated. Dr. O’Brien said that at her clinic they start at 25mg/day and increase to 25mg BID after a few days, and then gradually increase the dose to as high as 100mg BID.
Narcotics
Buprenorphine (buccal mucosa or via injection) can be used short-term or for any painful procedure or for the arthritic cat prior to routine procedures such as a radiograph or blood collection. It has been a useful addition in multimodal pain control for chronic pain as needed.
Tramadol
Tramadol is a narcotic-like pain reliever. When given once a day at half the suggested dose, it is well tolerated by cats and can be used for analgesia. At this lower, once-a-day dose, the euphoria that cats traditionally exhibit with this medication is reduced or nonexistent.
Amantadine
Alone, amantadine is not a particularly good analgesic, but in combination with other analgesics, it may help alleviate chronic pain. Dr. O’Brien said that she does not use this drug, as most of her feline patients are a challenge to medicate: “The struggle in my mind outweighs the benefit based on what we currently know about this medication.”
She stressed that regardless of the drug mentioned above, the starting dose should be low in the geriatric cat, and increased in small increments. Her experience is if the senior cat is feeling is too sedated initially, the client will not be compliant.
Chondromodulating agents
Chondroitin sulfate and glucosamine may slow progression or alter the disease process involved with osteoarthritis by stimulating cartilage matrix synthesis, inhibiting catabolic enzymes, and increasing fluidity of synovial fluid.
Omega-3 fatty acids have an inhibitory effect on arachidonic acid, which is a key player in the inflammatory pathway in arthritic joints.
Green-Lipped mussel studieshave shown that this unique shellfish is a rich natural source of omega-3 fatty acids and naturally contains glucosamine and chondroitin sulphate.
Diet
Dr. O’Brien said that if a cat is obese it should be on a calorie-restricted, weight-loss diet with supplementation. Recommendations about nutrition, the amount of food to feed, and how-to-feed should occur for every cat, every visit. If the cat will not eat a supplemented joint/mobility diet, then a high-quality veterinary diet is advised, and supplemented with products that contain glucosamine, chondroitins, and omegas. She added that studies are limited in this area.
Other options
Injectable chondroprotectants may be helpful as theyprovide the raw materials to build more cartilage and produce more synovial fluid. In addition, they contain anti-inflammatory properties that slow damage to the cartilage and promote joint repair.
Cartrophen (pentosan polysulphate)and Adequan® (polysulphated glycosaminoglycan) may slow the progression of arthritis.
Therapeutic lasers have no clinical evidence, but anecdotally they are said to be effective in moderating pain and inflammation.CVT
