Pain Flashcards
What are the 3 dimensions of pain?
What are some of the effects of unrelieved pain?
Neuroendocrine : hypoglycaemia, weight loss, ↓wound healing, impaired immune system
Cardiovascular : Fatigue, immobility, weakness
Respiratory: ↓ lung volume leading to atelectasis & hypoxaemia
GIT & urinary: ↓bowel motility leading to constipation, anorexia, ileus, urinary retention
MSK: ↓muscle function & spasm leading to weakness, immobility & fatigue
Psychological: fear, anxiety leading to poor sleep, ↓coping, PTSD
What are some commonly used pain assessment scales?
Simple Descriptive Scale (SDS)
Numerical Rating Scale (NRS)
Visual Analog Scale (VAS)
Composite Pain Scales (e.g., CMPS-Feline)
Feline Grimace Scale
Equine Pain Scales.
Gait analysis
What are the challenges of pain scoring?
What is the most commonly used acute pain scale?
Glasgow Composite Measure Pain Scale (CMPS-SF)
How is the CMPS-SF structured?
Contains 30 descriptor options across 6 behavioral categories, including mobility.
Each descriptor is ranked numerically by associated pain severity.
The assessor selects the descriptor that best fits the dog’s behavior or condition.
There is a maximum score of 24
Describe how to use the CMPS-SF scale
- Initial assessment: Wait until recovery from anesthesia to evaluate
- Analgesia: Administer if scores are greater than 5/20 or 6/24
- Reassessment: Check 1h after analgesia; if pain scores drop below threshold, reassess in 2 hours
- Ongoing monitoring: Assess every 3–4hrs or as needed depending on analgesic class, route & duration
Scale is intended to be adjunct to clinical judgement
What is the scoring system of the CMPS-Feline?
pain score is sum of rank scores across 7 categories.
Maximum score: 20.
Analgesic intervention threshold: 5/20.
What are features of grimace/pain faces?
- Ear Changes: fold, curl & angle forwards or outwards, pointed shape
- Orbital Tightening: narrowing of orbital area,partial or complete eye closure orsqueezing
- Nose/Cheek Flattening: with eventual absence ofcrease between cheek & whisker pads
- Whisker Change:move forward away from face
What factors can be used to assess pain in cattle?
What factors can be used to assess pain in pigs
Wrinkling of snout
Ears held backwards
What factors can be used to assess pain in horses
trical/low ears or ears held stiffly backwards
Angled eye/tension above eye area & orbital tightening
Withdrawn & tense stare
Nostrils – square-like/strained
Tension of muzzle/strained mouth & pronounced chin
Tension of the mimic muscles/chewing muscles
What analgesics methods are used for acute pain management?
Opioids
NSAIDs
Local anesthetics
Ketamine and alpha-2 agonists
Cold therapy
Tissue handling.
What supportive care is essential in pain management?
Nursing care, including bandages, massage, IV line care, monitoring, range of motion (ROM), and ensuring sleep.
Gentle handling to minimize stress.
What is the tiered approach to managing perioperative pain of known cause?
- Start with opioids, NSAIDs, and local anesthetics.
- Include cold therapy and appropriate nursing care.
- Use ketamine and alpha-2 agonists if necessary.
- Consider physical modalities & anti-inflammatory diets
What are the targets for NSAIDs
Inhibit COX enzymes (COX-1 & COX-2), reducing prostaglandin production & alleviating inflammation & pain
Besides inflammation, what are the essential functions of prostaglandins in body?
Protect the stomach and intestinal lining.
Maintain kidney blood flow.
Support platelet function for blood clotting.
What are some common NSAIDs used in small animals?
Meloxicam
Carprofen
Robenacoxib
Firocoxib.
What are the most common equine NSAIDs
Phenylbutazone (suxibuzone), Flunixin meglumine, Meloxicam
What are the most common cattle NSAIDs
Meloxicam, Ketoprofen
Cattle and small ruminants should receive NSAIDs for
castration, disbud, assisted calving, foot care etc
In what patients is the use of NSAIDs contraindicated?
Renal or hepatic insufficiency (how bad?)
Hypovolaemia
Congestive heart failure & pulmonary disease
Coagulopathies, active haemorrhage
Spinal injuries
Gastric ulceration
Concurrent use of steroids
Shock, trauma
Pregnancy
What is Galliprant and how does it differ from traditional NSAIDs?
First-in-class prostaglandin receptor antagonist (PRA) that doesn’t inhibit COX enzymes but specifically targets EP4 receptor in inflammatory pathway
minimises side effects on GIT, kidneys & liver
What are the key features of paracetamol mechanism of action?
Blocks central & peripheral COX enzymes.
Works on CB1 & TRPV1 receptors to reduce pain & fever
In what species is paracetamol licensed?
Licensed in pigs
Can be used IV in dogs & horses, though not licensed for this purpose
Pardale-V (paracetamol & codeine) is licensed in dogs.
What are the three key opioid receptor types?
μ (mu): Produces spinal & supraspinal analgesia, euphoria, sedation, respiratory depression & decreased GI motility
κ (kappa): Produces spinal & supraspinal analgesia, sedation, dysphoria, diuresis & miosis
δ (delta): Produces spinal & supraspinal analgesia & cardiovascular depression
What are the classifications of drugs acting at opioid receptors?
Full agonists: Activate receptors fully (e.g., methadone)
Partial agonists: Partially activate receptors (e.g. buprenorphine)
Agonist-antagonists: Activate 1 receptor while blocking another (e.g., butorphanol)
Antagonists: Block receptor effects (e.g., naloxone).
What is pre-emptive analgesia and why is it used?
Pre-emptive analgesia involves administering analgesics before onset of pain
Reduces immediate post-operative pain, decreases pain intensity & duration & prevents peripheral & central sensitization
What is multimodal analgesia, and what is its benefit?
Multimodal analgesia combines different analgesics with various mechanisms of action
Provides additive analgesia while minimizing side effects by reducing individual drug doses.
What is opioid-induced hyperalgesia?
A phenomenon where long-term opioid use increases a patient’s sensitivity to pain
What is sequential analgesia?
technique using agonist-antagonist or partial agonist (e.g., butorphanol) to reverse excessive sedation or respiratory depression from full agonists while maintaining analgesia
How do opioids work at cellular level?
Opioids bind to G-protein coupled receptors, affecting enzyme activity, ion channel permeability & cell membrane hyperpolarization, inhibiting pain signals.
What are the two main classes of local anesthetics, and how are they metabolized?
Amino-esters: Hydrolyzed by plasma cholinesterases (e.g., procaine)
Amino-amides: Metabolized by the liver (e.g., lidocaine)
What is the mechanism of action of local anaesthetics?
Block Na channels by interacting with receptors located inside Na+ channel pore, preventing nerve impulse conduction
What are some safety considerations when using local anaesthetics?
have narrow therapeutic index, so overdosing is easy
Always aspirate before injecting to avoid intravascular administration
In case of overdose, use 20% intralipid IV
Give some examples of local anaesthetic uses
Lidocaine spray (Intubeaze): For cat intubation.
Proparacaine: To anesthetize cornea for ophthalmic procedures
EMLA cream: Lidocaine & prilocaine cream for topical anesthesia
Intratesticular block
IVRA (Intravenous Regional Anesthesia): Provides limb anesthesia in dogs by injecting anesthetic into vein after applying tourniquet
Brachial plexus block: Blocks nerves in forelimb for surgical procedures
Horn block
Splash block: Local anesthetic applied directly to a surgical site, such as orbit
Epidural block
Limb blocks
Infiltration anesthesia: Injected near surgical site, such as before incision closure.
What is the mechanism of action of alpha-2 agonists?
bind to alpha-2 adrenergic receptors, reducing norepinephrine release, leading to sedation, analgesia, & other systemic effects.
What are the cardiovascular effects of alpha-2 agonists?
Initial hypertension (due to B-receptor stimulation).
Followed by hypotension (A-receptor effects).
Decreased heart rate (HR) and cardiac output (CO).
Increased systemic vascular resistance (SVR).
ow do alpha-2 agonists affect the respiratory, urinary, and GI systems?
Respiratory: Mild depression of respiration.
Urinary: Increased urine production.
Gastrointestinal: Decreased motility.
What endocrine and thermoregulatory effects are associated with alpha-2 agonists?
Endocrine: Hyperglycemia & enhanced growth hormone (GH) release
Thermoregulation: Impaired, causing sweating.
What are the clinical uses of alpha-2 agonists?
Premedication or rescue analgesia for all species.
Short-lived analgesia (~1 hour).
Can be reversed with atipamezole.
Name some commonly used alpha-2 agonists in veterinary medicine
Medetomidine (Sedator)
Dexmedetomidine (Sileo)
Xylazine (Nerfasin)
Detomidine (Domidine)
What is ketamine used for in veterinary medicine?
Induction agent (dissociative anaesthesia).
Perioperative analgesia.
Restraint of fractious cats (e.g., sprayed in the mouth).
Sedation when combined with other drugs (IM or IV).
Useful in zoo and exotic animals.
How does ketamine work as an NMDA antagonist?
Blocks NMDA receptors on inhibitory neurons, reducing inhibition of glutamate release
Increased glutamate release triggers synaptic strengthening and formation
What are the potential side effects of ketamine?
Dissociative, psychotomimetic, and cognitive effects.
Peripheral side effects with prolonged or high-dose use.
How is chronic pain different from acute pain?
Chronic pain is multifactorial (involves mood, posture, and movement domains) and is subjective.
What are the tiers in chronic pain management?
Tier 1:
- First-line treatments with strong evidence for efficacy, including NSAIDs, anti-NGF monoclonal antibodies, omega-3s, exercise, environmental modifications, weight management, and surgery.
Tier 2:
- Adjunctive treatments with mixed or limited evidence, including steroids, disease-specific therapies, and physical modalities like acupuncture and laser therapy.
Tier 3:
- End-stage options with minimal evidence or significant limitations, such as tramadol, non–omega-3 supplements, IA biologics, and salvage surgeries.
How is chronic pain assessed?
Helsinki Chronic Pain Index
GuvQuest
Canine Brief Pain Inventory (CBPI)
Liverpool Osteoarthritis in Dogs (LOAD)
CSOM (Client Specific Outcome Measures)
Health-Related Quality of Life Questionnaires (HRQL)
What are some non-pharmacological adjuncts for pain management?
Hydrotherapy & physiotherapy
Chondroprotectives (glucosamine, PSGAGs)
Weight control & diet (omega-3 rich diets)
Acupuncture & rehab
Stem cell therapy & IRAP
What are Mesenchymal Stem Cells (MSCs)?
Progenitor cells that can differentiate into connective tissue, bone &cartilage cells.
Used in regenerative therapy for osteoarthritis (OA)
hat is the main mechanism of MSC therapy?
Once injected into OA lesion, MSCs differentiate into chondrocytes, releasing bioactive molecules with immunomodulatory & anti-inflammatory effects
How does CBD oil work in chronic pain management?
Acts on peripheral, spinal & supra-spinal sites to produce anti-nociceptive & anti-hyperalgesic effects.
What is the legal status of CBD oil for veterinary use in the UK?
Not licensed for use; vets must be aware of legal regulations before prescribing
What is the HHHHHMM scale?
quality-of-life assessment for end-of-life care in dogs, scoring from 0-10 in seven categories:
Hurt
Hunger
Hydration
Hygiene
Happiness
Mobility
More good days than bad
total score >35 is considered acceptable.
