Monday, February 29, 2016

25 Signs of Pain in Cats

Hero kept open-mouth breathing when he had urolithiasis (even though he also had bouts of chasing a toilet-paper roll around the bath).

Cats are experts at masking pain. We discussed this recently when we spoke to Dr Susan Little about signs of pain in cats, and now there is more research to add to the discussion.

Isabella Merola and Daniel Mills, from the University ofLincoln, set out to determine whether feline experts could achieve a consensus on the signs of pain in cats. They found over 80 per cent agreement that 25 signs were considered sufficient to indicate pain (i.e. sufficient to indicate pain when they occur, but not necessarily present in all cats with painful conditions).

They begin by acknowledging that there is now general agreement that pain – in humans and non-humans – is a multidimensional experience. It’s not just a matter of a physical sensation – the sensory aspect of pain relates to its intensity, location and duration. Pain also involves thoughts and feelings (what scientists call the affective-motivational domain) – this encompasses the emotional and unpleasant aspects. Put it this way, without emotions we wouldn’t have negative associations with pain. It would be just another physical experience.

Feline better on pain medication, post-operatively.
The authors reviewed the literature on feline pain and identified 67 signs that a 
cat might be in pain.

The study involved several rounds, the first to ascertain what conditions experts associated with pain in cats, also to find out if there were any other signs of pain in cats. There were: the list grew from 67 to 91.

Conditions the experts considered painful included orthopaedic conditions (conditions like arthritis, fractures); cancer (especially bone cancer); urinary tract disease (cystitis, urinary tract obstruction), pancreatitis, ophthalmic conditions (like uveitis), dental disease (tooth fractures, stomatitis, gingivitis), trauma, surgical pain, peritonitis, diabetes, bowel disease, foreign body ingestion, vertebral disc disease, thromboembolism, neuropathic pain, skin damage, dermatological conditions (burns, wounds, ear infections), visceral inflammation, oro-facial pain and cat fights. One might rate some of these conditions as more painful than others.

The experts whittled this down, agreeing on 25 signs and behaviours sufficient to indicate pain.
These were:
  • Lameness
  • Difficulty to jump
  • Abnormal gait
  • Reluctance to move
  • Reaction to palpation
  • Withdraw/hiding
  • Absence of grooming
  • Playing less
  • Appetite decrease
  • Overall activity decrease
  • Less rubbing toward people
  • General mood
  • Temperament
  • Hunched up posture
  • Shifting of weight
  • Licking a particular body region
  • Lower head posture
  • Blepharospasm
  • Change in form of feeding behaviour
  • Avoiding bright areas
  • Growling
  • Groaning
  • Eyes closed
  • Straining to urinate
  • Tail flitching

In addition, a number of other behaviours were considered unreliable for inferring pain but were present in cats with high or low level pain. These included signs like sitting more often (a very difficult parameter to evaluate in a species that sits even more than we do); panting (also associated with fear/stress); seeking contact with a person (some cats are people-cats, others most definitely are not); hissing (again, depends on the temperament); house soiling (can be due to feline politics); ear position; eye position; tension in the body and so on.

Of course there are some limitations. For example, signs must be interpreted in context – some of the listed behaviours might be related to the animal’s mood or temperament, or may occur due to a non-painful condition (for example, an abnormal gait can occur due to a non-painful neurological condition; a scared cat may freeze or withdraw or react explosively to palpation). The experts disagreed on things like the intensity of pain associated with certain behaviours, and no signs could be reliably linked to chronic conditions. Because it is so insidious and may not be associated with an initial, acute phase, chronic pain is more difficult to detect in cats. Sometimes we really don’t know until we trial pain relief.

As with people, cats are individuals and their expression of pain may vary significantly with personality, temperament and mood. The authors conclude that much work needs to be done to validate an observational instrument for assessing pain in cats, but the list itself is an excellent tool for vets and owners in considering whether a particular cat’s behaviour and signs are consistent with being in pain.

Reference

Merola I, Mills DS (2016) Behavioural Signs of Pain in Cats: An Expert Consensus. PLoS ONE11(2):e0150040.doi:10.1371/journal.pone.0150040


http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150040#abstract0

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