Assessment: Pain
Content
Pain Assessment
11/25/2010 1:07:00 AM
Structure and Function y Neuroanatomic Pathway o Pain- highly complex and subjective experience that origins at the CNS or PNS or both o Nociceptors- detect painful sensations from the periphery and transmit it to the CNS 2 primary sensory fibers for carrying pain signal A delta ± myelinated and larger in diameter; y transmit rapidly y localized, short-term, and sharp sensation C fibers- unmyelinated and smaller y Transmit slowly y Diffused sensation and aching o Persists after initial injury Sensory fibers enter the spinal cord by posterior nerve roots within the dorsal horn Synapse with interneurons located at the substantia gelatinosa layers of nerve cells pain signals cross over to the other side of SC ascend to brain by anterolateral spinothalamic tract y Nociception o Used to describe how noxious stimuli are typically perceived as pain 4 phases transduction y injured tissue release chemicals that propagate pain message (P, histamine, prostaglandins, serotonin, and bradykinin) transmission y pain impulse moves from the SC to the brain via spinothalamic tract perception y indicates conscious awareness of a painful sensation y only when the noxious stimuli are interpreted in these higher cortical
y
y
structures can this sensation be identified as pain modulation y descending pathways from the brain stem to the SC produce a 3rd set of neurotransmitters (serotonin, NE, neurotensin, GABA, opioids, B-endorphins, enkephalins, dynorphins) that slow down or impede the pain impulse²producing analgesic Neuropathic Pain (burning, shooting, and tingling) o A type of pain that does not adhere to the typical and rather predictable phases inherent in a nociceptive pain Abnormal processing of the pain message Difficult to assess and treat Pain perceived after injury heals Pain is sustained by an identified neurochemical o Mechanism Spontaneous firing of nerve fibers Hyperexcitability of dorsal horn neurons Hypersensitivity to typically innocuous stimuli Sources of Pain o Visceral Pain- originates from the larger interior organs (kidney etc) Transmitted by the ascending nerve fibers of ANS Presents ANS responses such as vomiting, nausea, pallor, and diaphoresis o Deep Somatic Pain Comes from blood vessels, joins, tendons, muscles, and bone o Cutaneous Pain- from skin surface and subcutaneous tissues Superficial, with sharp burning sensation o Psychogenic pain (obsolete term)- no known physical cause
y
y
o Referred Pain- felt at a particular site but originates from another location because both sites are innervated by the same spinal nerve Types of Pain o Acute Pain Short term and self limiting Often follows a predictable trajectory, and dissipates after an injury heals Serves a self-protective purpose o Chronic (persistent) pain 6 months or longer 2 further divisions malignant (cancer related) y parallels pathology created by tumor cells y induced by tissue necrosis or stretching of an organ by growing tumor nonmalignant y associated with musculoskeletal y e.g. arthritis, back pain, fibromyalgia doesn¶t stop when injury heals; it persists originates from abnormal processing of pain fibers from peripheral or central sites SUBJECTIVE DATA o Pain Assessment Tools Standardized Overall Pain Assessment Tools Useful for chronic pain conditions Particularly problematic acute pain problems E.g. y Initial Pain Assessment o Patient answers 8 questions concerning location, duration, quality, intensity, and aggravating/relieving factors y The Brief Pain Inventory o Asks the patient to rate the pain within the past 24 hours using
y
y
graduated scales (0-10) with respect to its impact on areas such as mood walking ability, and sleep y McGill Questionnaire o Asks the patient to rank a list of descriptors in terms of their intensity and to give an overall intensity rating to his or her pain Pain Rating Scales Unidimensional and are intended to reflect pain intensity Numeric Rating Scales Ask the patient to choose a number that rates the level of pain with 0 being no pain and 1 indicating worst pain Descriptor Scale Lists words that describe different levels of pain OBJECTIVE DATA o Pain should not be discounted when objective, physical evidence is not found o Physical exam Joints Muscles and skin Abdomen Nonverbal behaviors of pain Acute pain behaviors y Guarding, grimacing, vocalizations (moaning agitation, restlessness, stillness, diaphoresis, change in vital signs) Chronic pain behaviors y Little indication of pain so higher risk for underdetection²this is because of adaptation Reflexive Sympathetic Dystrophy (RSD)or Complex regional pain Syndrome (CRPS)
o Characterized by burning pain, swelling, stiffness, and discoloration of the extremity
11/25/2010 1:07:00 AM
11/25/2010 1:07:00 AM
11/25/2010 1:07:00 AM
Structure and Function y Neuroanatomic Pathway o Pain- highly complex and subjective experience that origins at the CNS or PNS or both o Nociceptors- detect painful sensations from the periphery and transmit it to the CNS 2 primary sensory fibers for carrying pain signal A delta ± myelinated and larger in diameter; y transmit rapidly y localized, short-term, and sharp sensation C fibers- unmyelinated and smaller y Transmit slowly y Diffused sensation and aching o Persists after initial injury Sensory fibers enter the spinal cord by posterior nerve roots within the dorsal horn Synapse with interneurons located at the substantia gelatinosa layers of nerve cells pain signals cross over to the other side of SC ascend to brain by anterolateral spinothalamic tract y Nociception o Used to describe how noxious stimuli are typically perceived as pain 4 phases transduction y injured tissue release chemicals that propagate pain message (P, histamine, prostaglandins, serotonin, and bradykinin) transmission y pain impulse moves from the SC to the brain via spinothalamic tract perception y indicates conscious awareness of a painful sensation y only when the noxious stimuli are interpreted in these higher cortical
y
y
structures can this sensation be identified as pain modulation y descending pathways from the brain stem to the SC produce a 3rd set of neurotransmitters (serotonin, NE, neurotensin, GABA, opioids, B-endorphins, enkephalins, dynorphins) that slow down or impede the pain impulse²producing analgesic Neuropathic Pain (burning, shooting, and tingling) o A type of pain that does not adhere to the typical and rather predictable phases inherent in a nociceptive pain Abnormal processing of the pain message Difficult to assess and treat Pain perceived after injury heals Pain is sustained by an identified neurochemical o Mechanism Spontaneous firing of nerve fibers Hyperexcitability of dorsal horn neurons Hypersensitivity to typically innocuous stimuli Sources of Pain o Visceral Pain- originates from the larger interior organs (kidney etc) Transmitted by the ascending nerve fibers of ANS Presents ANS responses such as vomiting, nausea, pallor, and diaphoresis o Deep Somatic Pain Comes from blood vessels, joins, tendons, muscles, and bone o Cutaneous Pain- from skin surface and subcutaneous tissues Superficial, with sharp burning sensation o Psychogenic pain (obsolete term)- no known physical cause
y
y
o Referred Pain- felt at a particular site but originates from another location because both sites are innervated by the same spinal nerve Types of Pain o Acute Pain Short term and self limiting Often follows a predictable trajectory, and dissipates after an injury heals Serves a self-protective purpose o Chronic (persistent) pain 6 months or longer 2 further divisions malignant (cancer related) y parallels pathology created by tumor cells y induced by tissue necrosis or stretching of an organ by growing tumor nonmalignant y associated with musculoskeletal y e.g. arthritis, back pain, fibromyalgia doesn¶t stop when injury heals; it persists originates from abnormal processing of pain fibers from peripheral or central sites SUBJECTIVE DATA o Pain Assessment Tools Standardized Overall Pain Assessment Tools Useful for chronic pain conditions Particularly problematic acute pain problems E.g. y Initial Pain Assessment o Patient answers 8 questions concerning location, duration, quality, intensity, and aggravating/relieving factors y The Brief Pain Inventory o Asks the patient to rate the pain within the past 24 hours using
y
y
graduated scales (0-10) with respect to its impact on areas such as mood walking ability, and sleep y McGill Questionnaire o Asks the patient to rank a list of descriptors in terms of their intensity and to give an overall intensity rating to his or her pain Pain Rating Scales Unidimensional and are intended to reflect pain intensity Numeric Rating Scales Ask the patient to choose a number that rates the level of pain with 0 being no pain and 1 indicating worst pain Descriptor Scale Lists words that describe different levels of pain OBJECTIVE DATA o Pain should not be discounted when objective, physical evidence is not found o Physical exam Joints Muscles and skin Abdomen Nonverbal behaviors of pain Acute pain behaviors y Guarding, grimacing, vocalizations (moaning agitation, restlessness, stillness, diaphoresis, change in vital signs) Chronic pain behaviors y Little indication of pain so higher risk for underdetection²this is because of adaptation Reflexive Sympathetic Dystrophy (RSD)or Complex regional pain Syndrome (CRPS)
o Characterized by burning pain, swelling, stiffness, and discoloration of the extremity
11/25/2010 1:07:00 AM
11/25/2010 1:07:00 AM
