U4 Pain and Fever
SS KNOW embryonic develop, spina bifida, CSF, blood brain barrier, ”fight or flight,” peripheral nerve damage
Somatosensory Function
Key Functions of Somatosensory System: Awareness of body sensations, including:
Touch
Temperature
Body position
Pain
Types of Sensory Neurons: Three types based on distribution and sensation:
General Somatic Afferent Neurons:
Widespread throughout the body.
Detect pain, touch, and temperature sensations via various receptors.
Special Somatic Afferent Neurons:
Receptors located primarily in muscles, tendons, and joints.
Senses body position and movement.
General Visceral Afferent Neurons:
Receptors located on visceral structures.
Sense fullness and discomfort. (Bautista, 2024a, p. 398)
Pain
Definition of Pain:
"Unpleasant sensory and emotional experience associated with, or resembling that associated with, actual and potential tissue damage" (International Association for the Study of Pain, 2020).
Clinical Significance:
Most common reason individuals seek clinical attention.
Varies widely in intensity; affects all age groups.
The experience of pain results from both sensory perception and stimulation.
Pain perception can be separated from the individual's reaction to pain.
Pain distress more influenced by individual reaction than pain intensity.
Includes anatomical, physiological, psychological, social, cultural, and cognitive factors.
Factors Influencing Pain Reaction:
Anxiety
Culture
Gender
Age
Past experiences
Expectations regarding pain relief (Bautista, 2024a, pp. 405-406)
Pain Threshold and Tolerance
Pain Threshold: The point at which a stimulus is perceived as painful.
Pain Tolerance: The maximum amount of pain an individual is willing to endure.
Associated with diminished efficacy of drugs due to repeated administration.
Influencing Factors:
Psychological, familial, cultural, and environmental factors greatly affect pain tolerance (Bautista, 2024a, p. 411).
Types of Pain
Classification of Pain: Based on:
Duration: Acute or chronic.
Location: Cutaneous or deep and visceral.
Site of Referral: Useful for planning management interventions.
Examples of Conditions Causing Pain:
Surgery, trauma, cancer, sickle cell disease, and fibromyalgia (Bautista, 2024a, p. 411).
Acute and Chronic Pain
Distinction Based on Duration:
Widely accepted classification characterized by time interval, typically six (6) months.
Conditions can exhibit both acute and chronic components (e.g., osteoarthritis, cholecystitis).
Differences in Diagnosis and Therapy:
Acute and chronic pain differ in etiology, mechanisms, and psychological outcomes.
Importance of Differentiation: Pain research emphasizes understanding the distinction between acute and chronic pain for effective treatment (Bautista, 2024a, p. 411).
Acute Pain
Definition: Pain elicited by injury to body tissues and activation of nociceptive stimuli at the injury site.
Purpose: Functions as a warning system, prompting individuals to seek assistance for potential tissue damage.
Characteristics:
Generally short duration (< 6 months).
Resolves when underlying pathology resolves (self-limiting).
Essential diagnostic clues derived from the pain's onset, location, duration, characteristics, timing, severity, and aggravating/relieving factors (e.g., OLD CARTS method) (Bautista, 2024a, pp. 411-412).
Chronic Pain
Definition: Pain that persists longer (> 6 months) than expected after an inciting event, can last for years.
Presentation: Highly variable, lacking autonomic and somatic responses associated with acute pain.
Characteristics:
Pain may serve no useful or protective function, leading cause of disability.
Accompanied by loss of appetite, sleep disturbances, depression, and other debilitating effects (Bautista, 2024a, p. 412).
Biological Factors Affecting Chronic Pain:
Peripheral Mechanisms: Persistent stimulation of nociceptors tied to chronic musculoskeletal and visceral disorders.
Peripheral-Central Mechanisms: Abnormal functions in peripheral and central parts of the somatosensory system leading to chronic pain phenomena like causalgia, phantom limb pain, and postherpetic neuralgia (Bautista, 2024a, p. 412).
Central Mechanisms: Associated with central nervous system (CNS) diseases/injuries; characterized by abnormal sensations like burning and hyperalgesia (Bautista, 2024a, p. 412).
Cutaneous and Deep Somatic Pain
Cutaneous Pain:
Originates from superficial structures; accurately localized, often distributed along dermatomes.
Characteristics: Sharp pain, may have a burning quality, abrupt or slow onset.
Deep Somatic Pain:
Arises from deeper structures (e.g., periosteum, muscles, tendons, joints, blood vessels).
Diverse stimuli (strong pressure, ischemia, tissue damage) can evoke deep somatic pain.
Characteristics: More diffuse than cutaneous pain (Bautista, 2024a, p. 412).
Visceral Pain
Definition: Common pain arising from visceral organs, often linked to disease.
Origin: Visceral nociceptive afferents travel via cranial and spinal nerve pathways of the autonomic nervous system.
Differences with Somatic Pain:
Neurological mechanisms and perception differ.
Strong contractions, distention, or ischemia can induce severe visceral pain.
Lower nociceptor density in viscera compared to skin (Bautista, 2024a, p. 412).
Referred Pain
Definition: Pain perceived at a site different from its origin, innervated by the same spinal segment.
Characteristics:
Commonly applies to visceral pain felt as originating from the body wall.
Referred pain may occur alone or alongside pain at the stimulus's source.
Guarding→ may compress blood vessel→ muscle ischemia→ localized and referred pain g
Diagnostic Implications: Difficulty arises from the lack of correspondence between pain location and noxious stimuli origin.
Hypothesis: Visceral and somatic afferent neurons converge on the same dorsal horn neurons, challenging the brain's ability to pinpoint pain origins (Bautista, 2024a, p. 412).
Pain Assessment
Components:
Nature, severity, location, and radiation of pain.
Careful history to identify triggering factors (injury, infection, disease).
Comprehensive Pain History:
1) Pain onset
2) Description: localization, intensity, quality, pattern
3) Relieving/exacerbating factors
4) Individual's reaction to the pain.
Preference: Eliminating the pain's etiology more desirable than just treating symptoms (Bautista, 2024a, p. 414).
Pain Measurement Methods:
Numeric Pain Intensity Scale: Range from 0 (no pain) to 10 (most intense).
Visual Analog Scale: A line representing the continuum of pain intensity.
Verbal Descriptor Scale: Numeric ranking of pain severity with descriptors (Bautista, 2024a, p. 414).
Alterations in Pain Sensitivity and Special Types of Pain
Sensitivity Variability: Pain sensitivity and perception differ among individuals and may fluctuate in one person under various conditions.
Pathophysiology: Irritation, mild hypoxia, or compression of a peripheral nerve leads to hyperexcitability of sensory nerve fibers:
Hyperesthesia: Unpleasant hypersensitivity.
Hyperalgesia: Heightened painfulness.
Types of Hyperalgesia:
Primary Hyperalgesia: Occurs in damaged tissues.
Secondary Hyperalgesia: Occurs in surrounding uninjured tissues.
Possible Hyperalgesia Etiologies: Increased sensitivity to noxious stimuli, decreased nociceptor threshold, increased pain from suprathreshold stimuli, windup phenomenon (Bautista, 2024a, p. 418).
Other Alterations in Pain Sensitivity:
Hyperpathia: Prolonged and unpleasant sensation following a sensory threshold.
Paresthesia: Spontaneous, unpleasant sensations (e.g., pins and needles).
Dysesthesia: Distorted and often unpleasant somesthetic sensations.
Analgesia: Absence of pain in response to noxious stimuli without loss of consciousness.
Individuals unable to sense pain risk tissue damage.
Congenital Indifference to Pain: Normal nerve impulse transmission absent perception of painful stimuli, normal transmission but messed perception at high levels
Congenital Insensitivity to Pain: Peripheral nerve defect resulting in nonperception of pain
normal transmission but zero preception
Allodynia: Pain from non-noxious stimuli, linked to central and peripheral sensitization (Bautista, 2024a, p. 418).
Special Types of Pain
Neuropathic Pain:
Condition resulting from dysfunctional neurological systems.
Can result from peripheral nerve involvement, leading to various sensory disturbances and unexplainable widespread pain.
Conditions Inducing Neuropathic Pain:
Nerve entrapment, compression from tumors, various neuralgias (trigeminal, postherpetic, posttraumatic).
Diabetes Mellitus: Length-dependent neuropathy affecting long axons in peripheral nerves (Bautista, 2024a, pp. 418-419).
Neuropathic Pain Characteristics:
May be persistent or intermittent, associated with allodynia or stabbing, jabbing, shooting sensations.
Diagnosis depends on onset, distribution of abnormal sensations, quality of pain, and associated conditions (e.g., complex regional pain syndrome) (Bautista, 2024a, pp. 418-419).
Neuralgia→ pain along a nerve pathway
Definition: Characterized by severe, brief episodes of lightning-like or throbbing pain along a spinal or cranial nerve distribution, often triggered by cutaneous stimulation (Bautista, 2024a, p. 419).
Trigeminal Neuralgia
Common Characteristics:
Severe, stabbing, unilateral, intermittent recurrent facial pain without numbness, characterized by spasms or tics.
May be aggravated by chewing, tooth brushing, or touch (Bautista, 2024a, p. 419).
Postherpetic Neuralgia
Characteristics: Chronic pain persisting post-herpes zoster infection (shingles), marked by constant or intermittent pain and potentially stimulus-evoked pain (Bautista, 2024a, p. 419).
increase risk after age 60
Phantom Limb Pain
Characteristics: Neurologic pain following limb or part of limb amputation; can be tingling, cramping
severe pain associated with the end of a nerve regeneration trapped in scar tissue
Headache and Associated Pain
Headache
Prevalence: Common health issue, can represent primary disorders or secondary symptoms of other diseases.
Diagnosis and Challenges: Requires comprehensive history and exam to rule out serious conditions (meningitis, tumors). Maintain headache diaries to track contributing factors (Bautista, 2024a, p. 420).
Types of Headaches
Common Types:
Migraine headaches
Tension-type headaches
Cluster headaches
Chronic daily headaches (Bautista, 2024a, p. 420).
Migraine Headaches
Evaluation: Comprehensive assessment including family history, potential triggers, medication list, menstrual cycle, and symptom characteristics (location, frequency, duration) (Bautista, 2024a, p. 420).
Etiology and Pathogenesis:
Autosomal dominant inheritance; affected by hormonal variations, commonly in assigned-at-birth females.
Triggered by activations of the trigeminal nerve leading to neurogenic inflammation and vasodilation (Bautista, 2024a, pp. 420-421).
Clinical Manifestations of Migraines
→ common in poverty, elderly, and women
Categories:
Migraine without aura (85% cases) - typically lasts 1-2 days with features including one-sided, pulsating pain and nausea.
Migraine with aura - may include reversible speech disturbances or visual symptoms preceding the migraine (Bautista, 2024a, p. 421).
Chronic Migraines: Occur at least 15 days monthly, may include transformed migraine symptoms (Bautista, 2024a, p. 421).
Common in women and children
Cluster Headaches
Characteristics and Manifestations: Severe unilateral pain typically behind the eye, restlessness, and ocular symptoms (lacrimation, conjunctival redness) (Bautista, 2024a, p. 422).
Tension-Type Headaches
Description: Most common headaches, often described as dull and diffuse, do not significantly interfere with daily activities (Bautista, 2024a, p. 422).
Chronic Daily Headaches (CDH)
Definition and Characteristics: Occurs 15+ days monthly, retains migraine and tension-type features, with potential for rapid onset without prior headache history (Bautista, 2024a, pp. 422-423).
Children and Pain
Take children’s and neonates pain seriously
Children can accurately report pain, 3-8 year old→ use facial pain scales
Older Adults
May be fearful to report pain
Self-report is the most reliable but look at behaviors too
Body Temperature Regulation
Thermogenesis: Comprises all mechanisms underlying heat production, significantly affected by metabolic rate and external environmental factors.
Core Temperature Range: Defined limits of 36.0ºC to 37.5ºC (97.0ºF to 99.5ºF), influenced by diurnal variations, 0300-0600 lowest temp.
Hypothalamus Function: Acts as the thermal control center, responding to peripheral and central thermoreceptor feedback, ensuring core temperature balance.
Core Temperature Evaluation Methods:
Skin temp is not reliable
Rectal, oral, or urinary measurements, with the rectal temperature being the most reliable (Bautista, 2024a, pp. 426-427).
Mechanisms of Heat Production
Primary Source: Metabolism, influenced by numerous factors including hormonal influences and activity level.
liver and heart working
Thermogenesis → BMR, food digestion, muscle activity, hormones
Factors Impacting Core Temperature
Vasoconstriction and Vasodilation: Modulated by sympathetic nervous responses to control body temperature fluctuations through heat gain/loss mechanisms (Bautista, 2024a, p. 427).
Diaphoresis: Enhanced sweating regulated by the autonomic nervous system to assist in short-term cooling (Bautista, 2024a, p. 427).
Hyperthermia: Condition defined by increased body temperature without change in the hypothalamic set point (Bautista, 2024a, p. 427).
Fever
Definition of Fever: Elevation of body temperature due to upward displacement of the hypothalamic thermostat from pyrogens; enhances immune response but can lead to complications (Bautista, 2024a, pp. 428-429).
Phases of Fever: Include p8rodrome, chill, flush, and defervescence, which encompass physiological responses to increasing body temperature.
Diagnosis and Treatment: Identification of underlying causes is critical to manage fever effectively (Bautista, 2024a, pp. 431-432).
Conduction→ direct heat transfer of heat from one molecule to another
Cooling blanket→ lowering fever via conduction
Children and Fever
< 3 months old→ mild fever = serious infection
Older adults→ blunted febrile response
confusion and AMS happens quickly with fever
Hyperthermia
heat stroke→ life threatening
Sx: tachycardia, N/V, weakness, emotional lability, delirium
SIRS→ respiratory failure
“heat cramps”→ salt depletion d/t fluid loss from heavy sweating
Hypothermia
Definition and Risk Factors: Core temperature below 35ºC; at-risk populations include the elderly and infants, along with those with certain medical conditions (Bautista, 2024a, p. 435).
Clinical Manifestations: Include pupil dilation, weak pulse, respiratory depression, and possible confusion (Bautista, 2024a, pp. 436-437).
Moderate to severe: CO2 drops as temp drops→ drops respiratory drive→ can be fatal
Conclusion
Understanding somatosensory function, pain assessment, headache types, and body temperature regulation is paramount in nursing and healthcare. The knowledge gained in these areas supports effective patient care and management strategies through recognition, diagnostic evaluation, and treatment.