Anaesthesia: Management of Long Term Pain and Locoregional Anaesthesia SS Flashcards
What is chronic pain?
‘whatever the animal’s behavioural changes, combined with their motivational states, tell us it is’
Pain that outlasts the original injury and expected healing time or that a specific period
Changes in central pain processing (hyperalgesia and allodynia)- Maladaptive
What are the different types of chronic pain?
Nociceptive/inflammatory
neuropathic
neoplastic
mixed
reffered
myofascial
sympathetically mediated pain?
What is myofascial pain?
Significant component of many chronic pain states- often underdiagnosed
Has myofascial trigger points- arise due to muscle ‘wear and tear’, damaged motor end plates causes acetylcholine release and therefore local sarcomere contraction leading to distinct knot or taut band
Commonly affects postural muscles- neck, shoulder, lumbar and hip
There is a specific palpation technique which gives dramatic response
May occur secondary to postural strain, blunt trauma, spinal pain
What are the implications of chronic pain?
Sensory, emotional, cognitive, motor, welfare and quality of life
‘suffering’
How can chronic pain be assessed?
Quantitative sensory testing
Force plate analysis- lameness
Validated chronic pain scales
- e.g. - Glasgow University Vet School questionnaire (GUV-Quest)
- Liverpool Osteoarthritis in Dogs (LOAD)
- Canine Brief Pain Inventory (CBPI)
- Helsinki Chronic Pain Index (HCPI)
- Feline Musculoskeletal Pain Index (FMPI)
What are some common behavioural changes in dogs with chronic pain?
- Reduced enthuiasm or play and initiating plah
- Reduced excercise tollerance
- Change in interaction with owner (more clingy)
- Change in attitude towards other people- agressive, seperation anxiety
- More restless
What are some common behavioural changes in cats with chronic pain?
- Reduced enthsiasm
- Reduced jumping to access higher areas
- Change in interaction with owner
- Less time spent outside
- Change in urination behaviour
- Reduced use of scratching post- overgrown claws
- Appetite- increased or decreased
- More time spent sleeping
- Change in grooming behaviour
How should you approach a case of chronic pain?
- Identify owners concerns and expectations
- Identift the problem and classify the type of pain for each source
- Identify aims of pain management
- Devise treatment plan
- Implement plan for review and provide clear outcome measures
PLATTER- plan, anticipate, treat, evaluate, return
What is the acroym for the treatment of chronic pain?
ABCDE
Analgesia
Body weight
Control of complications
Disease modifications
Excercise
What are the different ways to achieve analgesia?
Analgesic Drugs
Analgesic interventions- acupuncture, physiotherapy, hydrotherapy etc
1) What is an example of an NSAID?
2) What are there MOA?
3) What needs to be considered with long term use?
4) What are the potential side effects?
- Metacam
- Cox 1/2 inhibitors
- Serum biochemistry testing and urinalysis indicated with long term use
- Multiple side effects- GI, hepatic, renal, coagulation
1) What is grapiprant?
2) What is its marketed use?
3) What is its mode of action?
4) What are its side effects?
- Non-steroidal, non-cox inhibiting anti-inflammatory drug
- Marketed as first line treatment but useful if dogs cannot tolerate NSAIDs
- PGE2 EP4 receptor antagonist- involved in development of pain and inflammation
- Common side effect- mild transient vomiting
1) What are anti-NGF monoclonal antibodies?
2) What is the name of the canine and feline antibody products?
3) How often is it administered?
4) What are its side effects?
- Monoclonal antibodies produced against nerve growth factors that contribute to OA pain
- Canine- bedivetmab, Feline Frunvetmab
- SC injection every 4 weeks
- transient skin irritation
Take care- self injection can often lead to hypersensitivity
Rapid progression of OA reported with concurrent use in humans
For how long is paracetamol use licensed with in dogs?
What is it’s MOA?
Liensed for 5 days orally with codeine
MOA not fully understood
Can be used with/without NSAIDs
1) What class of drug is tramadol?
2) What is tramadol’s mode of action?
3) What is tramadol licensed for in dogs?
- Atypical opioid- weak mu receptor agonists
- Inhibits serotonin and noradrenaline reuptake- M1 metabolise has greater analgesic efficacy
- Licensed for acute and chronic mild soft tissue and musculoskeletal pain
1) How effective is tramadol in cats and dogs?
2) What can it mask when used with NSAIDs?
3) What are its side effects?
- Efficacy in dogs varies, can be effective in cats- slower clearance of M1 metabolite
- Can mask GI pain
- Side effects- salivation, vomiting, dysphoria, sedation, seizures
1) What are examples of NMDA antagonists?
2) How long it their onset?
3) What are their side effects?
- Ketamine, amantadine, Memantine- other 2 not licensed
- Slow onset 3-4 weeks
- Common side effects transient GI signs, may cause agitation/restlessness, may lower seizur threshold
1) What is the MOA of gabapentin and pregabalin?
2) What are they used to treat?
3) What are they marketed for?
4) What are their side effects?
5) What could stopping them abruptly do?
- Calcium channel antagonists
- Neuropathic pain
- If animal cannot tolerate NSAIDs
- Sedation, vomiting, ataxia
- May cause seizures
Pregabalin- oral absorption more rapid and predictable
1) What kind of drug is amitriptyline?
2) What chronic pain can it be used to treat?
3) What is its MOA?
4) What side effect can it cause?
- Tricyclic antidepressant- not licensed in veterinary species
- Neuropathic pain
- Central opiod receptor activity and serotonin and noradrenaline reuptake inhibitor
- May cause cardiac arrythmias
What chronic pain are bisphosphates used for?
Pamidronate or zoledronate for BONE PAIN
What is acupuncute indicated for?
Indicated for OA pain and central sensitisation- limited vet studys
What is the purpose of physiotherapy?
to rehabilitate, muscle strengthenin for myofascial pain, includes passage for passive movement
What is hydrotherapy good for with chronic pain?
Helps to regain fitness, strength and balence
Less pressure on joints
What is photobiomodulation useful for in chronic pain patients?
May be useful in irritable animals that won’t tolerate accupuncture
Limited evidence, riskof themral injury