Page 10 - Chiron Autumn 2018

8 CHIRON CALLING
This is the second in a two part series that will look at Osteoarthritis (OA), in the dog. This article will cover the treatment and prevention of OA in the dog. After the previous article the reader should have an appreciation of OA diagnosis and causes.
The predominant drug of choice for canine osteoarthritis are pain killers due to the painful nature of the condition. The common first line drugs are the non steroidal anti inflammatory drugs (NSAIDs), of which there are many trade names. Speak to your veterinary team to advise on branding.
The main side effect of NSAIDs is gastrointestinal (GI), upsets. Should a dog on long term NSAIDs start GI issues stopping the drug will often lead to a resolution and the NSAID can be restarted. Some manufacturers claim to have reduced GI side effects compared to other drugs but the evidence is equivocal.
When starting long term drug therapy routine blood test and urinalysis should be performed and repeated at routine intervals. It is unlikely that the drug will cause any long term damage but given that OA patients are more likely to be older animals undiagnosed concurrent diseases are possible such as liver or kidney disease, and NSAIDs may further exacerbate these problems. Many people will often try to reduce the dose of NSAIDs, which anecdotally I have seen success with. Currently it is thought that this can lead to dogs remaining in pain due to under dosing, but we are often told to dose to lean weight, not actual body weight. With an overweight dog, first start a weight reduction diet, but secondly reduce the dose of NSAID to the lean weight of the animal and monitor pain at home in conjunction with your veterinary team.
NSAIDs relieve pain to a limit, and usually at some point the pain from the ongoing OA will increase past the pain relieving capabilities. Increasing the dose of NSAIDs does not add any more pain relief (and more cause more side effects), but adding a second drug will increase the pain relief. The most rational drug to be added is paracetamol, of which the mechanism of action is still to this largely unknown. Most veterinary paracetamol
comes premixed with codeine but the codeine does not seem to be active in most dogs. Anecdotally I have seen dysphoria in dogs that have started paracetamol and I have presumed this is the codeine having an effect. Upon stopping the drug, the dysphoria ceased.
Beyond NSAIDs and paracetamol there are further drugs available including Amantadine and Gabapentin. Both of theses drugs are extremely powerful and may cause dependencies if used long term. You may have to pulse therapy, that is give a short dose and then monitor the response and potential relapse. Where relapse occurs long term therapy is likely to be required if other methods listed below are not possible or do not work.
Where there has been a specific trauma to a specific joint, intra joint treatments have a place in removing the need for system wide treatment. Intra-articular steroid injection can massively reduce the inflammation in a single joint. Where
Exercise management is an oft forgotten technique with dogs that have OA
more than one joint is affected the dose of steroid is split between the joints to avoid GI issues. Future treatment options may include stem cell therapy but at the moment there is very little evidence available to show positive effect.
Exercise management is an oft forgotten technique with dogs that have OA. If one evening after a walk your dog seems more painful than the previous day, consider reducing the length of walk the next day. This may seem simple but it is rarely carried out and can massively reduce the need for extra drug therapy. Avoid the weekend warrior syndrome; this is where the dog has a standard length walk during the week but goes on a hike at the weekend! Younger dogs will cope with this fine but older animals with OA will struggle.
There are many veterinary and human supplements that claim efficacy with
treating, preventing or reducing pain with arthritis. The most common supplement used are glucosamine and hyaluronic acid. The only supplement shown to have a positive effect in large double blinded control trials are omega three fatty acids. These can be given to dogs as a tablet (Yumove), or fed in the feed with clinical diets (Hills J/d or Virbac HPM-J). If a supplement does not contain omega 3, then it is simply not conferring any benefit beyond the placebo effect, which is well understood to be transferred to animals.
Where there has been an initial traumatic injury such as a cranial cruciate ligament rupture or a fracture, muscular imbalances will inevitably be present. Physiotherapy can be used to identify muscular imbalances and then corrective exercises can help reduce the impact of this. Even where trauma has not been present the chronic nature of OA can lead to similar imbalances and physic can help to limit the muscular impact. Alternatively hydrotherapy can be used to reduce the weight bearing nature of exercise and can be used to build muscle strength with a reduced strain. Where possible physiotherapists should be registered with the Association of Chartered Physiotherapists in Animal Therapy (ACPAT), to ensure quality standards are met.
Many veterinary practices will offer low level laser therapy (LLLT), to decrease the time for wounds/incisions to heal and for pain relief for both chronic and acute injuries. Whilst there is strong positive evidence for LLLT in human medicine the evidence base in veterinary medicine remains equivocal with a low number of quality trials (trials with double blinded control groups). This is still a valid treatment option but should be used alongside traditional medical interventions.
Throughout this article the author has discussed the root causes of OA, the risk factors, possible prevention and treatment plans. Hopefully the reader is now more aware of the disease as well as more aware of the treatment plans both pharmaceutical interventions and with options at home outside of drugs.
Hydrotherapy is a useful and fun adjunct to rehabilitation for dogs. Courtesy of Canine Hydrotherapy Association.