Veterinary Pain Management Quiz

Pain Management in Veterinary Medicine

• Pain is a sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. (International Association for the Study of Pain, 2018)
• Nociception is the neural process of encoding and processing noxious stimuli. (Loeser & Treede, 2008)
• Recent improvements in pain management have been made, but pain is still under recognized and under treated. There is a lack of licensed drugs and knowledge in this field.

Learning Objectives

• Define pain, analgesia, hyperalgesia, and allodynia.
• Understand components of the pain experience.
• Classify pain as acute, chronic, nociceptive, inflammatory, and neuropathic.
• Describe physiology of nociception, transmission, central and peripheral sensitization and descending inhibition.
• Outline behaviours associated with pain in domestic species.
• Employ pain scoring systems to recognize acute & chronic pain in domestic animals.
• Assess pain severity based on pathophysiology.
• Define pre-emptive analgesia and multimodal analgesia.
• Describe mechanism of action, uses, and potential adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs), paracetamol, opioids, ketamine, local anesthetics, gabapentin, pregabalin, amantadine, bedinvetmab, and frunevetmab.
• Describe alternative pain management therapies.
• Apply analgesic planning and create analgesic plans for common clinical scenarios.

Pain Physiology

• Transduction: Conversion of noxious stimuli to an action potential at the level of nociceptors. Nociceptors include specialized free nerve endings located in skin, muscles, joints, viscera, and meninges.
• Transmission: Transmission of pain signals. Primary afferent neurons (C and Aδ fibers) transmit poorly localized/dull pain (C fibers) and well localized/sharp pain (Aδ fibers). Secondary or projection neurons transmit pain-specific impulses through the spinal cord.
• Modulation: Inhibition or facilitation of pain signals occurs at spinal levels. Descending inhibitory pathways modulate nociceptive input.
• Projection: Transmission of nociceptive signals to the brain. Nociceptive information is transported to the brain via the spinal cord, reticular formation, hypothalamus, and pons.
• Perception: Brain’s process of integrating nociceptive information and processing the conscious experience of pain. Processing happens at multiple brain regions, including the somatosensory cortex, insular cortex, and others.

Pain Classification

• Acute Pain: Results from trauma, surgery, or infection and resolves in days or weeks. It is self-limited.
• Chronic Pain: Persists beyond the normal healing time (1-3 months). It can arise from disease.
• Nociceptive Pain: Caused by activation of nociceptors by noxious stimuli. Usually involves damage to tissue, including thermal stimulation, chemical stimulus, or mechanical stimulus.
• Inflammatory Pain: Tissue damage and inflammation activate nociceptors. Inflammatory mediators (prostaglandins, bradykinin) sensitize and activate nociceptors. This helps drive the inflammatory response, promoting healing of tissues.
• Somatic Pain: Well-localized and intense, often aching, sharp pain located in superficial or deep tissues.
• Visceral Pain: Diffuse, poorly localized, often dull pain arising from internal organs. Referred pain is when pain from one part of the body is perceived in another part.
• Neuropathic Pain: Damage or malfunction of the somatosensory system (peripheral nerves, spinal cord, or brain). Characterized by maladaptive low-threshold pain. Conditions include hypersensitivity and allodynia.

Pain Classification (Continued)

• Allodynia: Pain sensation in response to non-painful stimuli.
• Hyperalgesia: Exaggerated pain sensation in response to normally painful stimuli.

Pain Treatment

• Pre-emptive Analgesia: Administering analgesics before the noxious stimulus occurs.
• Multimodal Analgesia: Using more than one pharmacological class of analgesic to target different pain receptors. This generally leads to reduced side effects.
• Opioids: Reduce pain perception while also decreasing the activation of the descending inhibitory pathways. Opioids interact with opioid receptors in the brain to alleviate pain by reducing nociceptive transmission.
• Local Anesthetics: Block Na+ channels, hindering pain transmission. Lidocaine, bupivacaine, and ropivacaine are examples.
• NSAIDs (Nonsteroidal Anti-inflammatory Drugs): Reduce inflammation.
• Paracetamol: Has a weak analgesic and anti-inflammatory effect.
• Ketamine: Non-competitive NMDA receptor antagonist which interacts with multiple pain receptors.
• Alpha 2 adrenoreceptor agonists: Analgesia with shorter duration compared to sedation.
• Gabapentin and Pregabalin: Effective for neuropathic pain and seizures and associated with the blockade of Ca2+ channels.
• Amantadine: NMDA receptor antagonist that may be useful for chronic pain.
• Anti-nerve growth factor monoclonal antibodies: Reduce pain from NGF-mediated cell signaling.

Pain Assessment

• Behavioral Assessment: Observing species-specific behaviours like body posture, vocalizations, and interactions.

• Physiological Parameters: Monitoring heart rate, blood pressure, and respiratory rate. Other physiological parameters include plasma cortisol levels and catecholamines.

• Pain Scales: Utilizing scales like the Glasgow Composite Pain Scale (GCMPS) and other multidimensional scales for acute and chronic pain.

• Facial Pain Scales (GRIMACE): Evaluating animal pain based on facial expressions and actions.

• Pain Assessment (Continued)

• Chronic Pain Scales: Including those such as the Helsinki Chronic Pain Index (HCPI), Canine Brief Pain Inventory (CBPI), Cincinnati Orthopedic Disability Index (CODI), Health-Related Quality of Life (HRQL), Liverpool Osteoarthritis in Dogs (LOAD), Feline Musculoskeletal Pain Index (FMPI).

Pain Assessment (Continued)

• Other factors in chronic pain assessment: Evaluating changes in mobility, activities of daily living, mood and demeanor, response to stimuli or social interactions.
• Additional acute pain assessment techniques: Tools such as pressure mats and accelerometry provide quantitative information about gait analysis and pain responses, and can include sensory testing.
• When to assess pain?: Assessment should be performed at the time of admission, prior and after procedures or treatments, and periodically throughout treatment or recovery.

Non-Pharmacological Treatments

• Acupuncture: Insertion of needles in specific areas for pain relief, potentially decreasing analgesic drug needs.
• Physiotherapy: Treatments like hot/cold therapy, laser therapy, massage, and hydrotherapy. This improves blood flow and enhances tissue healing while also alleviating pain.
• TENS (Transcutaneous Electrical Nerve Stimulation): Low-voltage electric currents to manage pain and inflammation via gate control theory and endorphin release.

Case Discussions

• Examples of case discussions involving Clementine, Florence, and Bear offer scenarios to help students understand how to manage pain in veterinary practice.

Test your knowledge on effective pain management practices in veterinary medicine. This quiz covers key concepts such as pain assessment techniques, types of pain, and specific challenges in evaluating pain in animals. Perfect for students and professionals in the veterinary field.