Pain Assessment PDF

# UNIT 2 GENERAL EXAMINATIONS ## Chapter 6: Pain Assessment ### Structure and Function #### Neuroanatomy Of Pain * **Peripheral Nervous System:** * A-delta transmits pain impulses rapidly and is described as sharp or stabbing. * C fibers are slower and described as achy and ongoing....

# UNIT 2 GENERAL EXAMINATIONS ## Chapter 6: Pain Assessment ### Structure and Function #### Neuroanatomy Of Pain * **Peripheral Nervous System:** * A-delta transmits pain impulses rapidly and is described as sharp or stabbing. * C fibers are slower and described as achy and ongoing. * Both are referred to as nociceptors. * Nociceptors release substances: substance P, bradykinin, and prostaglandins which help transmit pain signals to the brain. * **Central Nervous System:** * Pain stimuli synapse in the spinal cord and are transferred to the central nervous system. * The perception is controlled by a combination of pain-facilitating and pain-blocking impulses and substances received by the body. * Pain stimuli pass through the spinal cord into the lateral spinothalamic tracts, to the thalamus, and then into the limbic system. * In the limbic system, emotions are produced before the sensation is recognized as pain in the cerebral cortex. * This whole process takes milliseconds. * Substance P and glutamate are important for pain transmission. * Glutamate activates receptors, intensifying and prolonging persistent pain. * Serotonin inhibits glutamate, decreasing pain transmission. * Healthcare providers prescribe medications that increase serotonin levels such as tricyclic antidepressants and selective serotonin reuptake inhibitors to treat chronic pain. * **Clinical Significance:** * Descending nerves transmit responses. * Inflammatory mediators create vasodilation, plasma extravasation, and skin sensitization in collaboration with substance P. * Cytokines can sensitize C-fiber terminals and increase pain. * Opiates, endorphins, and enkephalins bind to opiate receptors in the spine and block pain transmission. * Anti-inflammatory agents, antidepressants, and calcium-channel blockers are pharmacological alternatives to opioids in the treatment of pain. #### Gate Control Theory * The theory suggests that the body responds to painful stimuli through a "gating mechanism of neurons in the spinal cord. * Opening the "gate" means allowing pain to be produced while closing the gate creates a blocking effect to stop pain. * Continued painful stimuli on a peripheral neuron cause the gate to open, allowing pain. * Endorphins can block pain. #### Nociception * Nociception is the perception of pain by sensory receptors called nociceptors located throughout the body. * Nociceptors can produce pain resulting from heat, pressure, or noxious chemicals produced in the inflammatory process. #### Types of Pain * **Acute Pain:** * Acute pain serves as a warning system that some type of insult or injury has occurred. * Acute pain has a short duration with a known cause. * Examples include surgical pain and orthopedic injuries. * **Chronic Pain** * Chronic pain lasts longer than the normal healing period (3-6 months). * May not have a known cause. * Examples include low back pain and sickle cell anemia pain. * **Neuropathic Pain:** * Pain from a nerve injury. * Pain from damage to nerves in the peripheral or central nervous system. * Examples include diabetic peripheral neuropathy, postherpetic neuralgia, and postmastectomy pain. * **Nociplastic Pain** * Pain from altered nociception, yet without clear signs of tissue damage or disease. * Examples include: fibromyalgia, CRPS, chronic low back pain, irritable bowel syndrome, headaches, restless leg syndrome, temporomandibular joint disorder * **Visceral Pain:** Originates from abdominal organs and is described as crampy or gnawing. * **Somatic Pain:** Originates from muscles, bones, and joints and is described as sharp. * **Cutaneous Pain:** Originates from the dermis, epidermis, and subcutaneous tissues and is often burning or sharp. * **Referred Pain** Originates from a specific source but is felt at another site along the innervating spinal nerve. An example is heart pain felt in the neck or arm. * **Phantom Pain:** Neuropathic pain felt in an extremity or body part that is not there; for example, a patient experiences pain in a leg after an amputation. #### Clinical Significance of Pain * **Perception:** Pain is key to pain management and understanding pain. * **Risk Factors:** Those untreated for acute pain are at high risk for developing CRPS, neuropathic and nociplastic pain syndromes, and complex regional pain syndromes. * **Cognitive Impairment:** Older adults may experience cognitive impairment including dementia and delirium which makes pain assessment more challenging. * **Cultural Variations:** Cultural differences may exist in how patients communicate about pain. Healthcare providers should be mindful of unconscious bias and racial or ethnic influence on pain assessment and treatment. **Sex differences in pain:** * Female sensory nerves are more sensitive and excitable and have faster response rates than male sensory nerves, possibly due to estrogen. * Women report more pain than men. * Conditions such as fibromyalgia, irritable bowel syndrome, migraines, and TMJ pain are more prevalent in females than in males. * Men experience more pain relief from morphine than women. * Nurses need to be aware of sociocultural biases in pain, recognizing that men and women can be stereotyped differently and pain is often perceived differently based on gender. #### Chronic Pain * **Definition of Chronic Pain:** Nearly 1 out of 5 people experience chronic pain. * **Impacts of Chronic Pain:** Chronic pain has a high negative impact on people's lives including loss of income, medical expenses, and worker nonproductivity. * **Pain Management:** * For chronic pain a “pain management goal” is helpful and can be set with the patient. * Pain management goals can include: * Setting a functional goal based on what the patient cannot do because of pain, such as how far they can walk, or how much time the pain interferes with daily living. * Asking what makes the pain better and worse for the patient. #### Neuropathic Pain * Pain sensitization can occur making peripheral nociceptors more sensitive to painful stimuli. * Examples include neuropathic pain from inflammation. * Neuropathic pain can turn into chronic pain. #### Nociplastic Pain * Nociplastic pain has no identifiable cause. * Nociplastic pain is also considered to be central sensitization. * It is defined as pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage. * Examples of nociplastic pain include fibromyalgia, CRPS, chronic low back pain, irritable bowel syndrome, headaches, restless leg syndrome, and temporomandibular joint disorder. #### Windup * Windup occurs with repeated assaults on afferent neurons, causing the central nervous system to respond with an increased nociceptive response. * This causes the tissues in the affected area to become hypersensitive to pressure. * Windup is common in rheumatoid arthritis and osteoarthritis. ### Pain Assessment Tools * There are one-dimensional and multi-dimensional pain assessment tools. * One-dimensional pain scales measure the intensity of pain. * Multidimensional pain scales assess pain intensity along with psychological and functional elements of pain. #### One-Dimensional Pain Scales * One-dimensional pain scales aim to measure the degree of pain. * Examples of these scales include the Numeric Pain Intensity Scale, Visual Analogue Scale, and McGill Pain Questionnaire. * **Numeric Pain Intensity (NPI) Scale:** * One of the most widely used one-dimensional scales, * The NPI scale is a Likert-type scale, * It is comprised of O (no pain) to 10 (worst possible pain). * Patients are asked to select the number that best fits their pain. * The higher the score, the more intense the pain. * **Visual Analogue Scale (VAS):** * This is a 100-mm paper line with “no pain” at one end and “worst possible pain” at the other. * A patient is asked to place a mark on the line indicating the intensity of their pain. * It is a simple and basic one-dimensional pain scale, * Used for patients who are cognitively alert but verbally impaired. #### Multidimensional Pain Scales * Multidimensional pain scales are more complex and measure multiple aspects of pain such as intensity, mood, location, and medication efficacy. * Commonly used multidimensional scales include the McGill Pain Questionnaire (MPQ) and Brief Pain Inventory (BPI). * These scales are used in chronic pain, malignant pain and complex medical-surgical pain conditions. * **Brief Pain Inventory (BPI):** * First developed to measure pain in patients with cancer but is also used for chronic nonmalignant pain. * Has been translated into various languages. * Can be administered through an interview or self-report, * Includes a pain intensity scale, a body diagram, and evaluates a patient's functional ability, mood, and the efficacy of pain medications. * **McGill Pain Questionnaire (MPQ):** * A reliable and valid pain assessment tool. * Includes verbal descriptors, a Visual Analogue Scale (VAS), and present pain intensity rating. * The MPQ is a multidimensional pain scale that collects a detailed description of pain by asking questions about the location, intensity, quality, and onset of pain. ### Subjective Cues ### Priority Urgent Assessment * **Chest Pain:** * Chest Pain should be treated immediately because it may be a myocardial infarction. * Each minute a myocardial infarction progresses. * Chest pain can also be a sign of other serious conditions. * **Headache:** * The “worst headache of my life” is an emergency because it might indicate a cerebral hemorrhage. * A cerebral hemorrhage can be life-threatening. * **Acute Pain:** * Acute pain should be investigated and the underlying cause determined. * Signs of acute pain include high BP, tachycardia, diaphoresis, shallow respirations, restlessness, facial grimacing, guarding behavior, pallor, and pupil dilation. * **Lack of Pain:** * Lack of pain in the presence of acute injury may be a sign of spinal cord injury or severe impaired circulation or neurological dysfunction that could result in the loss of a Limp. * In the setting of a spinal cord injury when there is no pain, muscle paralysis, or weakness, and loss of feeling and muscle spasticity, the cord may be completely severed. ### Assessment Of Risk Factors * **Under Treated Pain:** Patients with untreated acute pain may have a higher risk of developing CRPS, neuropathic pain, nociplastic pain, and complex regional pain syndrome. * **Crush Injuries and Surgery:** If a patient has had surgery or a crush-type injury they are at higher risk for developing CRPS. #### Clinical Significance * **Patient Self-Report:** The patient's pain perception is the most important factor in pain assessment. * **Pain Assessment Tools:** One-dimensional scales are the most effective at measuring the intensity of pain. * **Pain Management:** Patient-directed pain management is a critical part of safe practice. * **Documentation:** Thorough, clear, and descriptive documentation is important to document the effectiveness of pain interventions. #### Objective Cues Table See Page 138 in text: table 1. **Physiological Pain Indicators Include:** * Agitation, restlessness, irritability, fear, anxiety. * Tachycardia, increased BP, increased oxygen demand, increased cardiac output, * Hyperventilation, hypoxia, * Nausea, vomiting, decreased bowel sounds, stress ulcers. * Reduced urine output, urinary retention, * Muscle tension, spasm, * Pallor, diaphoresis. * Increased catabolism, glucose, lactate * Impaired immune function **Behavioral Pain Indicators include:** * Depression, excessive sleeping, anxiety. * Isolation, impaired role performance, impaired home maintenance. * Moaning, groaning, grunting, sighing. * Stated pain, praying, counting, swearing, repeated phrases * Grimacing, clenching teeth, tightly shutting lips. * Facial masking, flat affect, wrinkling forehead, tearing. * Thrashing, pounding, biting, rocking, rubbing **Additional Objective Cues** * Pupils may be dilated * Respiration rate may be depressed * Blood pressure and respiratory rate may increase in the patient experience acute pain.