How do we assess pain in animals?

Question 1

1. What is acute pain?
2. What is chronic pain?

Answer 1

1. Last a short period of time – mins, hrs, weeks.
2. Lasts longer than a few weeks.

Question 2

Pain as a welfare issue.

Answer 2

• Acute pain is protective up to a point. e.g. will stop an animal walking on broken leg.
• Untreated / poorly treated pain can lead to an upregulation of the pain processing system making the pain harder to treat and establishment of chronic pain states.
• Untreated / poorly treated acute pain e.g. after surgery may lead to poorer patient outcomes and impaired healing due to physiological stress response.
• Untreated / poorly treated chronic pain will significantly reduce QoL.

Question 3

What does quantification of pain allow us to do?

Answer 3

• Categorise pain as absent, mild, moderate, severe – this will influence how we decide to treat it.
• Assess treatment efficacy – does the ‘pain score’ decrease if a treatment is used?
• Make judgement about QoL – should we treat this animal or is now the time to consider euthanasia?

Question 4

1. What are the challenges in assessing pain in animals?
2. What else (other than verbal comm.) can we use to assess pain?

Answer 4

1. • They cannot talk.
     - Just because non-verbal, does not mean they are not experiencing pain.
2. • Behavioural signs (preferred option in clinical cases).
     - Physiological signs (non-specific as may be affected by stress, infection, haemorrhage).

Question 5

Physiological signs associated with pain.

Answer 5

• Increased HR, BP, temp.
• Altered resp. (rate and pattern).
  – fairly non-specific and may be caused by all types of stressful event and exercise as well as illnesses.
• ‘Stress’ hormones like cortisol, noradrenaline, adrenaline etc.
  – Not instant but useful for studies.
• EEG (electroenceohalogram) activity.
  – Not instant – can be used for studies, but is this pain or nociception?

Question 6

Behavioural signs associated with pain.

Answer 6

• V. spp-specific.
• Varies between individuals within a spp e.g. depending on temperament.
• Prey spp. will tend to hide signs of pain so that they don’t stand out to a predator (true for horses and rabbits).
• All spp. (prey and predator) may hide signs of pain in a stressful environment like a vet clinic.
• Condition specific e.g. lameness with foot pain.

Question 7

Pain behaviours in cats and dogs that are similar to one another.

Answer 7

• Hunched appearance.
• ‘Pain face’.
• Lack of grooming.
• Inappetence.
• Specific signs like lameness (depending on the condition).

Question 8

Pain behaviour differences between dogs and cats.

Answer 8

Dogs
- Positive behavioural signs rather than a reduce repertoire.
- More likely to seek attention.
- Can be submissive.
- Can be aggressive.
- May be more likely to vocalise.

Cats
- Absence of a normal behavioural repertoire.
- Hide away at back of cage.
- Unwilling to relax.
- Fear aggression.
- Resent human contact.

Question 9

Rabbits in pain.

Answer 9

Prey spp.
Tend to make signs of disease.
Also in unusual environments may be immobile or freeze even when not painful.
Immobility particularly in patients with acute post-operative or traumatic pain.
Profound depression.
Eyes half-closed or shut.
Not grooming.
Avoiding attention.
Isolating themselves from other animals.
Bruxism (tooth grinding).
Abnormal body position e.g. hunched posture and abdo pressing.
Change in temperament.

Question 10

Horses in pain.

Answer 10

Some similarities and some differences in behavioural repertoire compared to dogs and cats.
Prey spp rather than predator.
Handling considerations – larger size.
‘Fight or flight’ means respond violently in severe pain.

Low head carriage.
At back of stable.
Vocalisation (groans, neigh).
Agitation.
Restless.
Weight shifting.
Tail swishing 9w/ no flies).
Lameness.
Limb lifting.
Abnormal distribution of weight.
‘Tucked up’ appearance.
Looking at painful body part.
‘Pain face’.
Bruxism.
Sweating.
Muscle fasciculations.

Question 11

Chronic pain additional indicators in all spp.

Answer 11

Some or all pain behaviours previously described.
Owner may describe changes in normal bhvr – sometimes put down to animal getting older and slowing down.
Unkempt coat if grooming difficult.
Loss of body condition / weight loss due to appetite loss and/or loss of muscle tone if exercising less.
Can be more restless and fidgety.
Signs associated w/ reluctance to move – some can be described by owner as loss of training (e.g. dogs and cats may toilet in house as cannot get out as easily).
Difficulty in assessing higher places.

Question 12

1. How is pain scored or quantified in human patients?
2. Can we use these in animal patients? – how?

Answer 12

1. Numerical rating scale e.g. 1-10.
   Or visual analogue scale.
   Simple descriptive scale.
2. Yes.
   – Caregiver awards score.
   – Usually observing animal’s behaviour to get a feeling for the level of pain.
   – Can be more accurate if do more than observe, like if you dynamically interact with the animal. (e.g. DIVAS = dynamic interactive visual analogue scale).
   – Can be a lot of inter-observer variation which can be an issue in practices with multiple caregivers.

Question 13

1. Aim of composite pain scales?
2. What does a composite pain scale consist of?
3. Process of validation of these?

Answer 13

1. To overcome some of the limitations of the VAS, NRS, and SDS. e.g. inter-observer variation.
2. Multiple items for each patient to be assessed on which are added up to give an overall score.
3. Lots of stats and clinical testing which requires careful selection of items.
   Testing to decide which ones to keep and which to remove.
   Refinement to ensure that the scores are repeatable between multiple users.

Question 14

1. Main validated scales for dogs and cats?
2. What do most pain scales suggest?

Answer 14

1. Glasgow group.
2. An ‘intervention level’ (usually analgesic meds).

Question 15

Dogs – Short Form - Glasgow Composite Scale…
1. What is important when carrying out the pain scales?
2. What is the maximum possible score if the dog cannot stand?
3. Maximum possible score if dog can stand?
4. Intervention level?
5. What is a drawback of this scale?

Answer 15

1. To follow the order on the sheet.
2. 20.
3. 24.
4. 5/20 or 6/24.
5. Poor differentiation between pain and sedation (issue in immediate postoperative period).

Question 16

Cats pain scale (Glasgow Feline Composite Measure Pain Scale)….
1. Maximum score?
2. Recommended intervention level?

Answer 16

1. 20.
2. 5/20.

Question 17

Composite pain scales for rabbits and horses?

Answer 17

Much less work on this than in dogs and cats.
Some recent publications for both but nothing currently widely used.

Question 18

1. What is the benefit of owner pain scoring compared to vet professional?
2. In what situations is this beneficial?
3. What can the practice provide the owner with to allow them to pain score their pet?

Answer 18

1. They know their own animal better than the vet professionals do.
2. Post-operatively and chronic pain.
3. Handouts / apps and some pharma companies have apps to accompany their products.

Question 19

What can be used to assess chronic pain.

Answer 19

Questionnaires that relate a lot to QoL rather than specifically asking questions about a pain score at a single point in time.
Species-specific and diease/condition-specific.

Question 20

1. What does CSOM stand for? – What does this allow for?
2. Advantages of CSOMs?

Answer 20

1. Client specific outcome measures.
   – A very personalised assessment of an animal’s chronic pain.
2. • Tailored to meet the individual behaviours and activities of each patient.
     - Quick to complete.
     - Easy to track changes over time.

Question 21

1. What else can be used as an add-on or standalone assessment? – What would this entail?
2. Advantages?

Answer 21

1. Videos.
   – Ask client to video pet weekly after the start of analgesic therapy to share with vet team.
2. • Useful as behaviour can be different in clinic.
     - Week-on-week record can be helpful to facilitate detection of change in an animal’s mobility.
     - Visible evidence of progress for owner which may help improve owner compliance with medication.
     - Owner and vet team can also see how other factors (e.g. sudden increase in exercise) impact behaviour.
     - Can use this with any companion animal spp.

Question 22

Why is assessment of health-related QoL useful?

Answer 22

• It can aid decision making about requirement for analgesia or timing for euthanasia.
• Improved patient well-being through “global” or holistic care i.e. not all about drugs.
• It can improve continuity of treatment between clinicians or treatment centres.
• It can help build and maintain the relationship between the veterinary professional and owner.