Chronic Pain: Origins and Treatment

• Chronic pain is a widely prevalent condition that requires a multi-faceted approach.
• Bonnie Wright, DVM, DACVAA, is certified in veterinary medical acupuncture, a pain practitioner, and canine rehabilitation.

Learning Objectives

• Comprehend the origins of chronic pain and its associated physiological changes.
• Design treatments for chronic pain using a holistic, integrative methodology.

Sources and Physiological Changes of Chronic Pain

• Chronic pain causes amplification of pain pathways.
• Can induce immune imbalances and kinesthetic/mobility changes.
• Affects fascia and soft tissue strain patterns.

Facilitated Transmission: NMDA Receptor

• The NMDA receptor increases glutamate in the spinal cord's dorsal horn.
• This process elevates calcium binding, which impacts ascending pain impulses in first and second-order neurons.
• NMDA receptors activate glial cells pre- and post-synaptically.
• Treatments should target both central and peripheral nervous systems.
• Genetics play a role in pain perception.
• Facial sheets can be implicated in chronic pain cycles and muscles.

Kinesthetics of Movement

• Compensation for pain may lead to support limb osteoarthritis.
• Myofascial strain patterns, tendon, and ligament injury.
• Alters body awareness and mobility.
• May cause increased tendency toward additional injury.

Immune/Inflammatory Aspects

• The balance of pro- and anti-inflammatory mediators changes during illness.
• Maximize response to infection or injury.
• Broad anti-inflammatories (steroids) are falling out of favor.

What is Fascia?

• Fascia is growing in appreciation in research, it was previously overlooked.
• Considered white connective tissue directly under the skin.
• Consists of deeper, broader bands that connect muscles and tendons and connect bones.
• Interstitium around the organs and vessels.

Clinical Relevance of Fascial Tissue

• Facilitates force generation and mechanosensory fine-tuning.
• Spontaneous regulation contributes to musculoskeletal dynamics.
• Untreated fascia may compound pain and dysfunction.
• Impacts balance and body awareness.

Role of Stretching in Connective Tissue

• Musculoskeletal pain origins may be unclear.
• Soft tissues can be a source if there is persistent inflammation.
• Alterations may precede back pain development.
• Connective tissue is home to the immune system, and can be a scaffolding for cancer.

Dosing and Usage

• Stretching the back improves gait, mechanical sensitivity, and inflammation in animal models.
• Viscoelastic changes in fascia happen quickly, while fibroblasts respond more slowly.
• Do not stretch beyond limits as it can cause ripping.

Analgesia for Pets: Pharma

• Opioids, NSAIDs, Alpha-2 agonists, TCAs, SSNRIs, Gabapentin, NMDA antagonists, among others
• Opioids are questionable for chronic pain because of neuro-inflammatory effects.
• Neuro-inflammatory, poor long-term efficacy, increases doses, poor bioavailability.

Emerging Evidence

• Evidence suggests that longer durations of NSAID treatment (6 months) leads to less arthritis and pain in dogs with OA.

Gabapentin

• Gabapentin helps to with hyperexcitability in the nerves and senses.
• Can cause sedation but is generally a useful drug for long term use.
• May be used to decrease pain/distress/anxiety in patients.
• Contraindicated in some patients.

Gabapentin Dosing

• 600mg tablets available in the US for larger dogs.
• Smallest capsule dose is 100mg.
• Liquid formulations however, contain xylitol.
• It is safer to buy formulated gabapentin to administer a smaller dose.

N-Methyl-D-Aspartate

• It is activated by recurrent depolarization, resulting in loss of Mg plug.
• When activated, it massively amplifies calcium release and thus, nerve transmission.
• It is a massive contributor to neuro-inflammation.
• Excellent drug targets, non-constructively active.

Amantadine and Memantine - NMDA Antagonists

• Initially approved as an anti-viral drug, but has a significant NMDA receptor antagonist effect.
• Can decrease the rate of neuro-degeneration in chronic conditions, even if non-painful.

Side Effects of Amantadine

• Overdose can cause arrhythmia and death, vigilance towards dosage is required.
• Use with caution in pre-existing seizures.
• If agitation occurs, recommended to dose amantadine in the morning, unless increasing to BID.
• Bitter, liquid suspension not well tolerated.

Obesity Increases Inflammatory State

• Dogs fed food for therapeutic weight management appear metabolically leaner.
• Reduction in weight is Analgesic and pro-inflammatory.

Diet Can Reduce Inflammation

• Fresh foods vs highly preserved foods.
• Reduced carbohydrates and processed meats.
• Food high in oxidants, fish, fruits and vegetables.

Challenges in Supplements

• Supplement industry has limitations in funds, nearly studies are fueled by companies.
• Current studies have limited quality, clinical response studies, use of placebos etc.

Dangers of NMDA Receptor Antagonists

• NMDA receptor antagonists can sometimes exacerbate underlying neurological dysfunction in aging.

Polysulfonated Glycosamino-Glycans

• It is clinically important to note its intra-articular approach in treating canine pain.
• This class of drugs significantly improved ROM and orthopedic score compared to placebo at 5 weeks.
• Dosing consists of, 4.4mg/kg IM twice weekly x 3 weeks.

Intra-Articular Treatment for OA

• Corticosteroids
• Local Anesthetics
• Platelet-rich plasma (PRP)
• Mesenchymal or bone marrow stem cells.
• Botulinum A neurotoxin
• Radiation therapy

Corticosteroids (Small Animal Medicine)

• Borrowed from equine and human data.
• Species-specific meta-analysis.
• Reduction in pain within 1-4 weeks.
• Considered a long-term treatment when combined with HA.

Hyaluronic Acid (Small Animal Med)

• Contradictory evidence regarding effectiveness and long-term benefit.
• Can modulate inflammatory reactions.
• Longer lasting effects than steroids (14-26 wks).

Regenerative Therapy

• Injections of small volumes of biologically active substances into joints and soft tissue.
• Used to promote tissue repair and growth, reduce pain and allow natural healing.

Synovetin OA

• Implicated in the pathogenesis of break the infectious cycle, and breaks the, cycle of inflammation and chronic pain.

Anti-NG Monoclonal Antibodies

• Anti-NG monoclonal antibodies help to influence pain to the body.
• Mab species are specific.

The Experience of OA Pain

• If you get an understanding that chronic pain takes over what started it.
• You have to manage it.

Non-pharma and Integrative Med

• This type of treatment will aim to improve both pharma and autonomic function (which is vago-sympathetic and immune function.)
• Cats are capable to regulate their homeostasis.
• It relies on working with homeostatic, patients, etc
• It includes opioidergic, serotonergic, noradrenergic, and endocannabinoid elements.

Non-Pharma and Modern Med

• Physiology provides to for the sensing or modifying pain.
• The overlap between systems is useful in mainstream, drug therapy is more in the clear.
• Complexities relating to studies as acupuncture and exercises relating random controlled trials.

The "pharmacologic” mechanisms of physical medicine modalities

• This includes temp deformation, mechanotransduction from fascia interactions, etc It includes:
• spams of Muscle flexibility,
• Modulation of the cartilage and joint function
• metabolism and blood flow

The Extreme / cosmic Power of Tissue Deformation

• This contains extreme cosmic powers.
• It incl: acupuncture, massage, exercise etc.
• The powerful modulation in soft tissue involves: skin, muscle, ligaments, tendons, fascia.
• it has growth factors

Important Promoters of De-Amplifying Neuromodulation

• Acupuncture
• Motion, Physiotherapy, Rehabilitation
• Vagal nerve stimulation
• Diet and Food Supplements