Week 7 Flashcards
What is Nociceptive pain
Pain produced by stimulation of specific sensory receptors or nociceptors located in the tissues
What is Somatic Pain
Sourced from skin/ subcutaneous tissue/ mucosa/ muscles/ tendons/ fascia/ joints/ bones/ lymph nodes
Pain is constant and well localised and often related to body position, movement and time
What is visceral pain
Affects internal organs, heart, lung, liver, GI tract, pancreas, kidney, bladder, uterus, deep lymph nodes
Pain is described as deep pressure or a dull ache, also may be colicky pain from obstruction, intermittent and gripping
What is Incident Pain
occurs only in certain circumstances, e.g. after a particular movement or on standing. Because of its intermittent nature, it is usually managed with local measures.
What is baseline pain
is pain that is generally constant in nature, and lasts at least half of the day
What is breakthrough pain
is defined as an unexpected increase in pain to greater than moderate intensity, occurring on a baseline pain of moderate intensity or less. Breakthrough analgesia should be administered at any time in addition to regular analgesia if the patient is in pain. Generally breakthrough analgesia is calculated between a 1/6 -1/10 of the background dose of analgesia in 24 hours.
4 Basic Steps of pain transmission
Transduction
Transmission
Modulation
Perception
Transmission- Primary afferent sensory neurone
A-delta fibres
Myelinated, fast
Sense extreme pressure & temperature
Well localised, sharp pain
C fibres
Unmyelinated, slow
Prolonged effect of pain
Poorly localised, dull, aching pain
Transduction of pain
The process by which afferent nerve endings participate in translating noxious stimuli (e.g., a pinprick) into nociceptive impulses
Fibers that respond maximally to noxious stimulation are classified as pain fibers or nociceptors
Noxious stimulation is first carried by the faster A-delta fibers and then by the slower C fibers
Local injury can cause nociceptors to become hypersensitive to noxious stimuli, thereby creating a condition called sensitization
Transmission of pain
The process by which impulses are sent to the dorsal horn of the spinal cord and the brain
The primary afferent neurons are active senders and receivers of chemical and electrical signals
The somatosensory cortex of the brain is thought to be involved in the sensory aspects of pain, such as the intensity and quality of pain
The frontal cortex and limbic system are thought to be involved with the emotional responses to pain
Spinothalamic pathways
Communicate with multiple parts of the brain terminating in the thalamus. These structures are responsible for pain localisation, intensity, emotional aspects and autonomic and affective responses
Spinoreticular pathways
Ascends through the brainstem to the cerebral cortex. Involved with mood, memory of emotions/response to pain and suppression of the pain response by the descending pain pathway
Descending Inhibitory Effects
Inhibition of ascending nociceptive input to brain by suppressing the release of pain producing neurotransmitters (e.g. substance P, NMDA, glutamate) Gate Open = pain
Descending Excitatory Effects
Stimulation of neurotransmitters that produce analgesia (e.g. endogenous opioids, noradrenaline, serotonin, GABA, dopamine) Gate Closed = pain suppressed
Functional Activity Score (FAS)
A = no limitation
> activity not restricted by pain
B = mild limitation
> activity is mildly to moderately restricted by pain
C = severe limitation
> the ability to perform the activity is severely limited by pain
