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