Canis ISSN: 2398-2942

Pain: assessment

Contributor(s): Jeff Ko, Jo Murrell, Sheilah Robertson

Introduction

  • One of the main goals of all those dedicated to working with animals is to relieve their pain. The benefits of pain management Pain: management are numerous and many safe and effective analgesic drugs and treatment modalities are now available for use in dogs and cats.
  • However, in order to treat pain we must first recognize it. Assessment of pain in animals is not an easy task but is essential to ensure our plan is effective.
  • Pain is a complex multidimensional experience involving both sensory and affective (emotional) components. It is now accepted that animals do experience pain even if they cannot communicate it in the same way humans do (Paul-Murphy J et al, 2004). Pain is a subjective and individual experience and humans show large inter-individual differences in quality, intensity and response to intervention which are genetically determined (Montagna P, 2007) and this is likely true in animals. Certainly, individual variation in response to opioids has been documented in cats (Lascelles B D & Robertson S A, 2004).
  • In animals, pain is what the observer says it is and because all judgments are subjective if we get it wrong, animals will suffer. The issue in animals is complex because we must consider differences in age, species, breed, and environment. Assessment systems must also take into account the different types and sources of pain, such as acute versus chronic or neuropathic pain, and visceral compared to somatic pain. In a clinical setting, there are no accurate objective measures of pain, such as heart rate, blood pressure or plasma cortisol levels (Conzemius M G et al, 1997; Cambridge A J et al, 2000; Smith J D et al, 1999) which is not surprising since these variables can be affected by many factors including fear and stress. Therefore pain assessment in animals must be based on behavior; either changes in, or loss of normal behaviors (eg grooming in cats) or the display of new behaviors (eg aggression in a previously friendly dog). Behavioral responses to pain vary greatly between species and even within a species. Few veterinarians would disagree that Labradors react differently to the Arctic breeds in the post-operative period. Ideally we must know the individual animals normal behavior and for this reason people who spend most time with the dog or cat, are invaluable in the assessment process; this is often the owner or veterinary nurses.
  • At this time there is no gold standard for assessing pain in animals, and it is obvious from the work of Holton and others (Holton L et al, 2001) with dogs that creating meaningful pain assessment tools is a painstaking and time-consuming task. In a recent survey only 8.1% of practices were using a pain scoring system yet 80.3% of veterinary nurses agreed they are useful clinical tools (Coleman D L & Slingsby L S, 2007). The key question for a busy practitioner is 'how well do the available scoring systems perform in clinical practice?' and what behaviors are most likely linked to pain.

Scoring systems

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Further Reading

Publications

Refereed papers
  • Recent references fromPubMed.
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  • Brown D et al(2008)Ability of the Canine Brief Pain Inventory to detect response to treatment in dogs with osteoarthritis. JAVMA233(8), 1278-1283PubMed.
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