Pathophysiology Chapter 6 Pain PDF

Chapter 6 Pain Copyright ©2024 F.A. Davis Company  Epidemiology of Pain  Protective mechanism  Most common symptom for seeking medical treatment  Optimal pain management Quicker rate of recovery Better...

Chapter 6 Pain Copyright ©2024 F.A. Davis Company  Epidemiology of Pain  Protective mechanism  Most common symptom for seeking medical treatment  Optimal pain management Quicker rate of recovery Better functioning Fewer postoperative complications Copyright ©2024 F.A. Davis Company  Pain: Ascending Signals Overview Structure Role Nociceptors Pain receptors A-delta fibers: large and myelinated C fibers: smaller and unmyelinated Spinothalamic tract Ascending pathway Carry pain signals to brain Brain Perception of pain Copyright ©2024 F.A. Davis Company  Pain: Descending Signal Overview Structure Role Brain Interpret pain sensory signal Sends outgoing signals Endogenous Natural analgesic neurochemicals opioids Endorphins, enkephalins, dynorphins Receptors on pain Opioids bind to receptors fibers Block signaling from pain fibers Copyright ©2024 F.A. Davis Company  Simple Reflex Arc  Protective responses that do not involve brain input  Example: patellar reflex Afferent neuron ‒ Incoming signal to dorsal horn of spinal cord Interneuron ‒ Connector Efferent neuron ‒ Outgoing signal from anterior spinal cord Copyright ©2024 F.A. Davis Company  Simple Reflex Arc (continued_2) Copyright ©2024 F.A. Davis Company  Spinal Cord—Brain Connection  Brain: interprets pain signals  Signals to and from brain Spinothalamic tract ‒ Primary ascending tract for pain signals Corticospinal tract ‒ Outgoing signals from the brain Copyright ©2024 F.A. Davis Company  Neurotransmitters and Pain  Excitatory or inhibitory >50 neurotransmitters involved with pain  Pharmacological manipulation of neurotransmitters for pain management Example: medications increase the level of the neurotransmitter, serotonin, to treat migraines Copyright ©2024 F.A. Davis Company  Neurotransmitters and Pain (continued_2) Neurochemicals Action Prostaglandins (from Enhances inflammation, pain, edema COX 1 enzymatic pathway) Interleukins Enhances inflammation, pain, edema Tumor necrosis factor Enhances inflammation, edema, and pain and decreases appetite Leukotrienes Enhances inflammation, edema, and bronchospasm, particularly in asthma and allergy Bradykinins Enhances inflammation Glutamate Amplifies pain signal Substance P Amplifies pain signal Enkephalins, Inhibitory influence on pain; natural opioid endorphins Copyright ©2024 F.A. Davis Company  Neurotransmitters and Pain (continued_3) Neurochemicals Action Acetylcholine Inhibitory action on pain in the spinal cord Gamma- Inhibitory action on pain in the spinal aminobutyric acid cord and brain Norepinephrine Inhibitory action on pain in the spinal cord Dopamine Inhibitory action on pain in the spinal cord and brain Serotonin Conveys analgesic signals from the PAG area to the NRM of the brain Diminished in migraine headache Copyright ©2024 F.A. Davis Company  Gate Control Pain Theory  Pain signals Travel to and from brain  Pain Not necessarily proportional to injury  Phantom pain Does not adequately explain Copyright ©2024 F.A. Davis Company  Steps of Gate Control Theory  Transduction Painful stimuli into neuronal signals  Transmission Traveling of neuronal signal  Modulation Influence of other neurons on the pain signal: GATE  Perception Conscious awareness of the pain Copyright ©2024 F.A. Davis Company  Neuromatrix Pain Theory  Explains phantom pain  Body-self neuromatrix located in brain Pain generated from nerve impulses of this matrix Develops from sensory input throughout a person’s life Brain can generate painful stimuli apart from nociceptive stimulation Copyright ©2024 F.A. Davis Company  Types of Pain  Acute Lasts hours or days and resolves with healing  Chronic Beyond expected time Can be due to persistent inflammation Does not serve a biological or protective function May profoundly affect quality of life  Neuropathic Injury or malfunction of nervous tissue Burning, tingling, paresthesia (pins and needles) Copyright ©2024 F.A. Davis Company  Sources of Pain  Cutaneous  Deep somatic Ligament, tendons Dull, poorly localized pain  Visceral Deep organs  Referred Pain occurs at a distance from actual pathology  Phantom Amputated part of body Copyright ©2024 F.A. Davis Company  Pain Assessment  5th vital sign  Pain is subjective  Variability among patients Nonverbal and verbal expressions may vary  Distinguishing features of pain Can aid in diagnosis Example: peripheral arterial disease causes leg cramps Copyright ©2024 F.A. Davis Company  OLDCART Pain Assessment Characteristic Example question Onset When did the pain begin? Location Where does it hurt? Can you point to where it hurts? Duration How long does it last? Characteristi What does it feel like? cs Aggravating Does anything make it worse? Relieving Does anything make it better? Factors Treatment Did anything make it better (pain Copyright ©2024 F.A. Davis Company medication, ice, heat)?  Visual Analog Scale Copyright ©2024 F.A. Davis Company  Pediatric Considerations Pediatric Pain Scales Neonatal Face, Legs, Premature Activity, Infant Pain Wong- Bieri- COMFORT Infants Crying, Profile Baker Modified Pain Scale scale Consolabili Revised FACES scale (NIPS) ty (FLACC) (PIPP-R) scale Copyright ©2024 F.A. Davis Company  Pediatric Pain Assessment Characteri stic facial responses to pain in infant Copyright ©2024 F.A. Davis Company  Wong Baker FACES Pain Scale Copyright ©2024 F.A. Davis Company  Geriatric Considerations Tendency to undertreat in older adults Especially when dementia is present Copyright ©2024 F.A. Davis Company  Dementia Patients and Pain Copyright ©2024 F.A. Davis Company  Diagnosis  Pain severity Assessed using reliable scale  May also use: Blood tests Nerve conduction studies Electromyography Nerve injection Imaging tools Copyright ©2024 F.A. Davis Company  Treatment: WHO Step Analgesic Ladder  If multiple pain relievers used, should have different mechanisms of action  Ladder used in bidirectional fashion Copyright ©2024 F.A. Davis Company  Treatment: Modified WHO Analgesic Ladder  Includes non-pharmacological modalities Copyright ©2024 F.A. Davis Company  Nursing Interventions Continue to monitor vital signs Dialogue Implementation Proper body positioning /Take Actions Healing touch Patient education Copyright ©2024 F.A. Davis Company  Three Major Classes for Pharmacological Pain Relievers  Opioids  Nonopioids  Adjuvant medications Copyright ©2024 F.A. Davis Company  Opioids  Considered a controlled substance  Morphine is prototypical opioid Produces analgesia, euphoria, and sedation  Most effective when given before pain onset  Can cause respiratory depression Additional side effects of opioids ‒ Constipation, nausea, dizziness, physical dependence Copyright ©2024 F.A. Davis Company  Complications of Opioid Use  Substance abuse Screener opioid assessment for patients with pain  Addiction  Tolerance  Withdrawal Buprenorphine ‒ Used to wean patients from opioids Naloxone ‒ Helps counter the effects of opioid overdose Copyright ©2024 F.A. Davis Company  Nonopioid Analgesics  Acetaminophen (Tylenol)  NSAIDs ’ Aspirin, ibuprofen, naproxen, celecoxib Block prostaglandin (PG) synthesis by inhibiting cyclooxygenase (COX) enzymes ‒ COX-1: gastric mucus production, platelet adhesion  Use of medications that inhibit COX-1 can affect GI mucosa ‒ COX-2: inflammation  Celecoxib is selective for COX-2 Copyright ©2024 F.A. Davis Company  Adjuvant Medications Adjuvant Medications Effect Antidepressants Can increase serotonin, norepinephrine, dopamine Local anesthetics Prevent nerve depolarization Peripheral-nerve Mainly used for post-operative pain blockade Injected Anti-inflammatory corticosteroids Anticonvulsants Help with neuropathic pain Topical pain relievers Lidocaine, capsaicin, NSAIDs Cannabinoids Potential to help manage pain in some disorders Copyright ©2024 F.A. Davis Company  Nonpharmacological Pain Management  Nursing  Guided imagery interventions  Intradiscal  Physiotherapy electrochemical  Occupational therapy therapy  Virtual reality  Acupuncture  Ultrasound-  Transcutaneous guided peripheral electrical nerve nerve stimulation stimulation  Botulinum (TENS) neurotoxin  Peripheral nerve  Psychological cryoanalgesia counseling Copyright ©2024 F.A. Davis Company  Questions, Comments, Concerns Copyright ©2024 F.A. Davis Company