As companion animals age, like humans, they are prone to experiencing chronic pain.
But chronic pain in dogs and cats is under-recognised and therefore under-treated.
I think the key reason for this is that most companion animal owners expect animals suffering from any kind of pain to behave as if they are experiencing acute pain.
Usually, acute pain is associated directly with an injury, like a laceration or fracture, that causes a sudden, obvious change in behaviour (a yelp, limping or running away from the source of the pain).
It's not uncommon for me to diagnose chronic pain in an animal, only for an owner to respond "but he doesn't cry!"
The truth is that animals in chronic pain rarely vocalise. In contrast to animals suffering from acute pain, animals suffering from chronic pain tend to have more subtle signs.
- Reduced mobility (for example, having trouble with or avoiding stairs, or not jumping onto furniture that they used to jump on);
- Stiffness (especially when getting up in the morning);
- Changes in posture (for example, a more hunched back or more pronounced bending of joints);
- Reduction in exercise or general activity;
- Reduced grooming (which can manifest as increased matting, knots in fur or just looking unkempt) or increased grooming around painful sites;
- Changes in eating, drinking or toileting habits;
- Weight changes (usually weight loss, but sometimes weight gain).
Chronic pain is associated with a range of conditions, most commonly osteoarthritis, but also other conditions like untreated dental disease and some kinds of cancer.
It affects animal welfare not only by causing pain, but by interfering with or preventing normal behaviour such as exercise, interacting with other animals or humans, eating, drinking, toileting or resting.
Often chronic pain is diagnosed when the underlying condition causing it is diagnosed.
Your veterinarian may use a pain-scoring tool such as a musculoskeletal scoring system or even a grimace scale, and may even ask you to fill out a questionnaire about the animal's behaviour.
Even then, chronic pain can be elusive.
Sometimes, a treatment trial may be used to detect chronic pain by looking for clinical improvement following the administration of a short course of pain relief.
Chronic pain is treated by treating the underlying cause where possible, and also treating the pain itself (for example with medication or physical therapies like physiotherapy or acupuncture).
The former is not always possible, as chronic pain can occur in the absence of an underlying cause, or may be due to an incurable or progressive condition, such as degenerative joint disease.
Management of chronic pain may also involve adjusting the length and frequency of physical activity (particularly for dogs), and adjusting the type of physical activities undertaken, for example by replacing vertical scratching surfaces with horizontal scratching surfaces, or replacing high-impact exercise like running and sprinting with lower impact exercise such as swimming or walking.
Environmental modification, such as providing a non-slip floor surface, adjusting the height of food and water bowls and/or providing a litter tray with at least one lower side to facilitate easy access may also improve comfort.
Regular health checks of senior pets are an important means of screening for signs of chronic pain. If you suspect that your companion animal is suffering from pain, contact your veterinarian.
Animals with chronic pain may be treated with multiple medications targeting different pain pathways.
Interventional pain procedures such as long-acting nerve blocks may provide extended pain relief.
Primary care veterinarians may liaise with specialists in veterinary anaesthesia in "pain clinics", just as human patients may be referred to pain clinic.
It is important that animals on long-term medication are re-evaluated by their veterinarian regularly to minimise the risk of side effects.
Ultimately, the diagnosis and treatment of chronic pain can make a huge difference to an animal's quality of life.
EPSTEIN, M. E., RODAN, I., GRIFFENHAGEN, G., KADRLIK, J., PETTY, M. C., ROBERTSON, S. A. & SIMPSON, W. 2015. 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats. Journal of Feline Medicine and Surgery, 17, 251-272
Dr Fawcett, BVSc (Hons), MANZCVS (Animal Welfare), Dip ECAWBM (AWSEL), is a lecturer at the Sydney School of Veterinary Science and a practising veterinarian.