Interview With Mike Petty, DVM: Pain Management in Dogs
Pain management in animals can be tricky, as it’s not always obvious that your pet is in pain.
The main reason for this? Some animals intentionally try to hide the pain they are in. “Although dogs and cats are carnivores, they are small carnivores and potential prey for larger carnivores,” says Mike Petty, DVM, a veterinarian and certified veterinary pain practitioner and acupuncturist. “Acting as healthy as possible is one way to avoid the attention they might otherwise receive from a larger (and hungry) carnivore that could see them as easy prey.” This instinctive behavior is still present in household pets.
Another reason we have trouble telling if an animal is in pain? According to Petty—the past president of the International Veterinary Academy of Pain Management and the co-author of the 2015 American Animal Hospital Association Pain Guidelines—pet owners don’t associate the behavioral changes brought about by pain as being connected to the pain itself. “Social withdrawal, reluctance to play, etc. are often written off by pet caregivers as, ‘My dog/cat is just getting old’.”
We asked Dr. Petty more about understanding and managing pain in dogs—and what you can do as pet owner to help ease the discomfort.
When observing your dogs, what obvious and not so obvious pain signs should you watch out for? Any signs that indicate acute/chronic pain or an emergency situation?
Mike Petty: The easy answer to this question is the signs of acute pain. Animals can seldom hide acute pain, especially if it is an emergency. Vocalization, guarding, even aggression toward their caretaker are often hallmarks of something that needs attention “right now.”
Many times I have caregivers tell me that their dog doesn’t seem to be in pain because he is not crying out in pain. Just like with humans, acute pain might make us cry out, but chronic pain seldom does. Instead, when looking for signs of chronic pain, you need to look for a dog’s reluctance to do those things that have the potential to cause pain: walking on slippery floors, jumping up or down from things like cars or furniture, refusing to play all but the least vigorous games. There may be other signs as well: trouble sleeping at night, sudden aggression toward other animals or people and decreases in appetite. These can be the result of many different diseases, and it often takes a trip in to the veterinarian to really know what is going on.
NSAIDs and steroids (corticosteroids) are often used to treat pain in dogs. What are the main differences between these two drugs and which one you find is more effective?
Mike Petty: I feel that it is the rare circumstance that corticosteroids should be used for pain. They have all of the side effects and potential problems that NSAIDS have plus more: immune system suppression, suppression of the adrenal and thyroid glands, dermatological systems, breakdown of ligaments… the list goes on. Classically, corticosteroids have been used for neurological issues, such as intervertebral disk disease, but recent years have given us some studies that show NSAIDS are as or more effective than corticosteroids when treating disk disease. When there is an immune issue as part of the pain, and we are looking for immune suppression, that is one good example when corticosteroids might be superior to NSAIDs
The biggest concern with NSAID use is the development of gastric ulcers. These can occur in dogs that have taken an NSAID for just a few weeks or for several years, suddenly and without much warning. I instruct all of my dog owners to watch carefully for signs of anorexia, vomiting, or dark tarry stool, all potential signs of an ulcer. Another common concern is that NSAIDs can impact renal function in those dogs that have borderline kidney function or are already in some degree of renal failure. The only way to monitor for this issue is regular blood work. Finally, the thing most people worry about, but actually happens rarely, is liver damage secondary to NSAIDs. Only about 1 in 10,000 dogs develop severe liver disease secondary to NSAID use. However, when it does happen, it is often fatal.
Aspirin is an NSAID, but should not be used in dogs. It is more likely to cause stomach ulcers than either approved animal NSAIDs or corticosteroids. Additionally, a recent study has shown that regular aspirin use in dogs can accelerate the breakdown of cartilage in the joints, hastening arthritis.
Be on the lookout for a new class of drug used for the treatment of osteoarthritis in dogs. One that will likely be on the market in 2016 is called grapiprant and is made by a drug company called Aratana Therapeutics. This drug does not appear to have the worrisome side effects of NSAIDs, corticosteroids or aspirin.
What about opioids? When are they a good option for treating pain?
Mike Petty: Opioids are considered the gold standard for the control of acute pain. They should be considered in all animals that are suffering from acute pain from things like trauma or anticipated pain from things like surgery.
Opioids for chronic pain have produced mixed results in animals. Often times, the level of medication needed to treat chronic pain also cause side effects, especially dysphoria. Dysphoria can lead to agitation, howling, etc. in dogs, seemingly making them more miserable than they would be without the opioids.
What are the major risks of pain management drugs? Is there any way to reduce those risks?
Mike Petty: As a general statement, it is more dangerous to NOT treat an animal in pain. Pain can severely inhibit normal function in animals, even seemingly simple things like eating, defecating and breathing. I see this all the time where some practitioners are reluctant to give a geriatric dog medication for fear of adverse effects. Each animal needs to be looked at as an individual, getting a complete physical exam, and diagnostics including blood work and radiographs. There is no one-size-fits-all approach and veterinarians that try to do so are usually the ones that see problems.
Would you say alternative pain treatment is best when used in conjunction with other treatments? What are the benefits of combining alternative and standard treatments?
Mike Petty: This is a complex question that does not have a simple answer. There are many treatments that are considered alternative, meaning doing something outside of and instead of Western medicine. For some treatments, such as laser treatments, rehabilitation (physical therapy) and acupuncture, there is a huge body of evidence that supports their use in the treatment of pain. For others, there is only marginal, but growing evidence such as stem cell therapy. And finally, there are things for which there is zero evidence: homeopathy and healing touch, to name a few.
Some alternative treatments like acupuncture are great for pain control especially in those patients that are intolerant of many of the pain drugs available to veterinarians. They can also be used in addition to mainstream treatments, and instead of calling them alternative, they are now called complimentary. Their use can reduce the amounts of things like pharmaceuticals, while at the same time adding to their benefits.
Is there any case where you would recommend the use of only alternative treatment?
Mike Petty: Many animals on chemotherapy have to avoid many different drugs. Acupuncture is great for that, as is physical therapy. Some geriatric dogs just seem to react to every pharmaceutical that is given to them, and these dogs benefit from alternative therapy as well.
How does acupuncture work to treat pain? Do some types of pain respond better than others to acupuncture?
Mike Petty: Acupuncture has its effect in 10 different ways that have been discovered so far. Some of these actions are complicated involving the brain, the pituitary and the adrenal gland, others are more straightforward such as the action of inserting the needle to bring the body’s own anti inflammatories into play near the site of needle placement and the “nerve talk” which can suppress pain when placed near the appropriate nerves. The best way to think about the action of acupuncture is that it directs the body to heal itself, often awakening pain-dampening mechanisms that have shut down due to the chronicity of the pain and the body accepting that pain as the new normal.
Chronic pain responds best to acupuncture, although there are many acute pain applications as well.
What other types of alternative pain treatments are available? How well do these work and when would you recommend?
Mike Petty: There are many modalities that are just now getting their feet wet and are starting to gather some evidence.
Stem cell therapy has been around for a while. This therapy consists of using the basic building blocks of all tissues, called stem cells, to inject into arthritic joints. It was originally hoped that new and healthy cartilage would grow from these stem cells, and certainly something does grow in the joint, but so far this therapy’s main anti-pain effect seems to be an anti-inflammatory one. The stem cells are surgically collected from the animal to be treated. The stem cells are then sent to a lab where they are checked for sterility and cell count, prepared for injection, and then sent back to be injected in the affected joint(s). This treatment is very expensive, although the price could come down, and the procedure could become less invasive, with the development and FDA approval of off-the-shelf stem cells.
Shock Wave therapy is another modality for the treatment of pain. This evolved from the shock waves that have been used for decades to break up kidney stones in people. It was found that these same shock waves also have a dampening effect on the pain of arthritis. There are different types and intensities of shock waves, and the best ones still need to be sorted out.
Platelet-rich Plasma is another therapy that has been getting some mixed results, but some of them positive. It works by separating the platelet-rich area of a blood sample and then re-injecting it back into the same animal, in an area of pain. More needs to be worked out, but this treatment does hold some promise.