Pain

Question 1

What is pain?

Answer 1

An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage

Question 2

What are the 3 dimensions of pain?

Answer 2

Sensory - discriminative (location, intensity, quality, duration)
Motivational - affective (how the pain makes you feel)
Cognitive - evaluative (influences behaviour)

Question 3

What are the risks of uncontrolled post-op pain?

Answer 3

Discomfort
Suffering
Delayed healing
Increased morbidity
Risk of developing chronic persistent pain

Question 4

What are the adverse effects of unrelieved pain?

Answer 4

Neuroendocrine e.g., hypoglycaemia, weight loss, slower wound healing
Cardiovascular - fatigue
Respiratory - decreased lung volume
GIT + urinary - decreased bowel motility => constipation, urinary retention
MSK - decreased muscle function
Psychological - poor sleep, PTSD

Question 5

Give examples of pain assessment tools

Answer 5

Physiological measurements/exam
SDS (simple descriptive scale)
NRS (numeric rating scale)
VAS (visual analogue score)
DIVAS (Dynamic, interactive visual analogue scale)
Composite scales
Pain faces
Acute vs chronic pain scales
Quality of life (QoL) scales
Analgesiometry & accelerometers
Gait analysis
Pressure sensitive walkways, platforms

Question 6

What are the disadvantages of SDS, NRS and VAS pain scoring?

Answer 6

Only consider intensity of pain - not sensory or affective qualities of pain

Question 7

What are the challenges of pain scoring?

Answer 7

Difficult, subjective, other drugs can affect the evaluation
Environment/owner/caregiver can affect the animal
Species variation
Interspecies variation
Domestication, hierarchy, feeding, aggression

Question 8

What is the most commonly used acute pain scale?

Answer 8

Glasgow Composite Measure Pain Scale (CMPS-SF)

Question 9

Describe the process of the Glasgow Composite Measure Pain Scale (CMPS-SF)

Answer 9

Evaluate the dog once it has recovered sufficiently from anaesthesia (as scores can be affected by the hangover effect of sedative and anaesthetic drugs)
If pain scores are greater than 5/20 or 6/24, consider giving analgesia
Allow the analgesic to take effect and reassess after an hour; if the score has decreased to below the intervention level, reassess in 2 hours. If not consider additional analgesia
Then assess every 3-4 hours or earlier as appropriate (depending on the severity of the surgical procedure and the class/route of administration/expected duration of analgesic administered) and after each analgesic administration
The scale is intended to be an adjunct to clinical judgment, and no animal should be denied analgesia on the basis of the scores alone

Question 10

Describe the use of the Glasgow Feline Composite Measure Pain Scale (CMPS-Feline)

Answer 10

clinical decision making tool for use in cats in acute pain
the recommended analgesic intervention level is 5/20.

Question 11

What are features of grimace/pain faces?

Answer 11

1. Ear Changes : fold, curl and angle forwards or outwards, pointed shape
2. Orbital Tightening: narrowing of the orbital area,partial or complete eye closure orsqueezing
3. Nose/Cheek Flattening: with eventual absence of thecrease between the cheek and whisker pads
4. Whisker Change:move forward away from face
5. Head position

Question 12

What factors can be used to assess cattle pain evaluation?

Answer 12

Tense stare/withdrawn
Tension of muscles above eyes
‘lines’ above nostrils
Strained nostrils
Increased tone of lips
Tension of facial muscles
Tense ears pointed backwards

Question 13

What signs of pain can be seen in pigs

Answer 13

Wrinkling of snout
Ears held backwards

Question 14

How can ear position be used to assess pain?

Answer 14

Question 15

How can orbital tightening be used to assess pain?

Answer 15

Question 16

How can muzzle tension be used to assess pain?

Answer 16

Question 17

How can whisker change be used to assessed pain?

Answer 17

Question 18

How can head position be used to assess pain?

Answer 18

Question 19

Describe facial features of equine pain

Answer 19

Distance between ears becomes larger
Muscles around eyes are stretched - sclera becomes more evident in medial canthus
Withdrawn stare
Dilated nostrils (side-to-side)
Tense facial muscles
Increased tonus of lips and tension of chin

Question 20

Give examples of ways to treat acute pain

Answer 20

Opioids, NSAIDs, local anaesthetics
Ketamine and alpha 2 agonists
Cold therapy
Good tissue handling
Nursing care (bandages, massage, IV lines, monitoring, ROM, ensuring sleep)
Other therapies (limited evidence) e.g. Laser, TRPV1 agonists, pulsed EMF

Question 21

How does the inflammatory pathway work?

Answer 21

After a cell is damaged, an enzyme called cyclooxygenase (COX) is activated. COX then stimulates the cell to produce substances called prostaglandins, which contribute to signs of inflammation such as pain, redness, warmth, swelling, and fever.

Question 22

What are the most commonly used small animal NSAIDs?

Answer 22

Meloxicam, Carprofen, Robenacoxib, Firocoxib

Question 23

When are NSAIDs contraindicated?

Answer 23

In patients with:
Renal or hepatic insufficiency
Hypovolaemia
Congestive heart failure & pulmonary disease
Coagulopathies, active haemorrhage
Spinal injuries
Gastric ulceration
Concurrent use of steroids
Shock, trauma
Pregnancy

Question 24

What are the most common equine NSAIDs?

Answer 24

Phenylbutazone (suxibuzone), Flunixin meglumine, Meloxicam

Question 25

What are the most common cattle NSAIDs

Answer 25

Meloxicam, Ketoprofen

Question 26

Describe the mode of action of grapiprant

Answer 26

Galliprant is an NSAID that does not block COX. It works lower down the inflammatory pathway by blocking some activity of a specific prostaglandin (EP4 receptor)

Question 27

What is the benefit of grapiprant over other NSAIDs?

Answer 27

targets canine pain and inflammation while reducing the impact on GI, kidney and liver homeostasis

Question 28

Describe the licensing of paracetemol

Answer 28

Used IV in dogs & horses (no licence) Pardale-V (paracetamol & codeine) has licence in dogs Licensed in pigs NEVER USE IN CATS

Question 29

Give examples of opioids

Answer 29

Morphine methadone pethidine fentanyl buprenorphine butorphanol tramadol

Question 30

What opioid receptor gives an analgesic response

Answer 30

Mu receptor

Question 31

What are the effects of activation of mu opioid receptors?

Answer 31

Question 32

What is the effect of activation of K opioid receptors

Answer 32

Question 33

What is the effect of activation of beta opioid receptors?

Answer 33

Question 34

Why should you always draw back when giving local anaesthetics?

Answer 34

To ensure you are not injecting into the blood supply

Question 35

What is the risk of local anaesthetics?

Answer 35

Narrow therapeutic index (easy to overdose)

Question 36

Where is the target of local anaesthetics?

Answer 36

located within the pore of the Na+ channel close to the cytoplasm and only the ionized, charged form of the local anaesthetic can interact with this receptor.

Question 37

What are the effects of alpha 2 agonists (a and b receptors)?

Answer 37

Sedation (a) Decrease MAC Analgesia (somatic & visceral) (a & b) Hyper (b) then hypotension (a) Decreased CO & HR, increased SVR Respiratory depression Increased urine production Decreased GI motility Decreased surgical stress response Hyperglycaemia, GH enhanced, Thermoregulation affected Sweating

Question 38

how can alpha 2 agonists be antagonised?

Answer 38

atipamezole

Question 39

What receptors do alpha 2 agonists act on?

Answer 39

a adrenergic receptors (presynaptic) b adrenergic receptors (post-synaptic)

Question 40

What are the uses of ketamine?

Answer 40

induction agent (dissociative anaesthesia) perioperative analgesic restraint of fractious cats (sprayed in mouth) Combined with other drugs for sedation (IM or IV)

Question 41

What is the mechanism of action of ketamine?

Answer 41

NMDA receptor antagonist on inhibitory neurons => glutamate release

Question 42

What can be found in tier 1 of chronic pain management?

Answer 42

COX-inhibiting and non-COX-inhibiting (EP4 receptor antagonist) NSAIDs Non-drug treatments: omega-3 fatty acids, encourage activity, environmental modification, weight management, surgery

Question 43

What can be found in tier 2 of chronic pain management?

Answer 43

Adjunctive drugs to tier 1 Steroids (cats and dogs) or acetaminophen (dogs only) - broad analgesics Intra-articular steroids Disease-specific drugs Therapeutic therapies - acupuncture, laser therapy etc.

Question 44

Describe tier 3 of chronic pain management

Answer 44

Intra-articular antibiotics Tramadol (lack of efficacy in dogs, cats have a strong aversion to its taste) Nutritional supplements localised surgical denervation

Question 45

What can be used as adjunctive to analgesia in chronic pain management?

Answer 45

Hydrotherapy & physiotherapy Chondroprotectives Exercise management Weight control & diet Joint replacement/salvage Anti NGF Ab (Librela, Solensia) Irap (Interleukin-1 Receptor Antagonist Protein) Accupuncture Other drugs: garlic & fenugreek, sodium hyaluronate (Hyonate), prednoleucotropin (PLT), steroids, paracetamol (not cats) Stem cell therapies (MCS)

Question 46

What is mode of action of mesenchymal STEM cells in chronic pain management? (adipose tissue-derived medicinal signalling cells)

Answer 46

exerted primarily through their secreted factors, including extracellular vesicles and bioactive molecules such as chemokines, cytokines and growth factors These paracrine factors have a range of immunomodulatory, anti-inflammatory, angiogenic and anti-apoptotic properties

Question 47

What is the effect of cannabinoids?

Answer 47

act on peripheral, spinal & supra-spinal sites to exert antinociceptive and antihyperalgesic effects (not licensed in UK)