A recent shift in focus towards more integrated pain and jointdisease research has prompted the formation of a new expert group, which hopes to apply the new knowledge to the management ofjoint pain in veterinary practice.
In the past, pain and joint disease have been considered as separateareas of research, with pain perceived simply as a consequence ofdisease. Over the last few years, however, it has become increasinglyapparent that the relationship is far more complex and that pain may bea driver of disease rather than just a consequence of it.
The group which had its inaugural meeting in Paris recently, brings together acknowledged veterinary experts in the fields of pain and joint disease. Its focus will be on the assessment and management of pain in canine osteoarthritis (OA), with the objective of educating veterinary surgeons to better understand and manage pain in canine OA and thereby improve the well-being of pets that suffer from this common disease.
“Central sensitisation” is one of the latest theories that has been suggested to explain the complex interaction between pain and disease progression in canine OA. Duncan Lascelles, associate professor of surgery at North Carolina State University, said that research has shown that the components of the pain pathway can change in response to a pain stimulus. Pain receptors “up-regulate” in response to painful stimuli and become more sensitive to subsequent pain.
CNS sensitisation is likely a significant contributor to chronic or maladaptive pain; this pain leads to decreased mobility, reduced muscle support and reduced muscle function, thus leading to disease progression. In other words, joint diseases cause pain, which in turn feeds back to create more disease.
Speaking at the meeting, Professor Lascelles said: “The link between the clinical signs associated with OA and joint pathology is not a simple one and may be much more complex than we have previously thought,” said Professor Lascelles.
“There is some evidence that COX inhibition reduces central sensitisation. And some evidence suggests that reducing central sensitisation may have a modulatory effect on disease progression by reducing signals going out to the periphery.
“The relationship between pain and disease progression is a very new area of research, and is at the forefront of our knowledge of how pain and joint disease are linked.”
John Innes, head of Division, small animal studies, University of Liverpool Veterinary School, told the meeting that OA is likely to be one of the major reasons for euthanasia of pet dogs in Europe. He and two co-investigators have performed a systematic review of the published evidence for the use of long-term, continuous NSAID treatment (at least 28 days) in OA. They found that this form of management is associated with better outcomes than short-term NSAID therapy, with no evidence of additional safety issues.
This review is to be published shortly.