Pain and Management Flashcards
Describe the Gate Control Theory.
Possible brain modulation, not just a passive system• Includes descending pathways
What are endorphins?
Endogenous opioids released within the brain and spinal cord
What is referred pain? Why do we have it?
WHAT: an error in perception by the sensory cortex in the brain as to the source of the painful stimulus (i.e., felt elsewhere than its true site)
WHY: cutaneous, visceral, and skeletal muscle nociceptors converge on a common nerve root of the spinal cord, but brain interprets as cutaneous (higher proportion)
What is the difference between segmental and extrasegmental referred pain?
SEGMENTAL: pain referred to a structure within the same dermatome
EXTRASEGMENTAL: pain referred to >1 dermatome (multiple levelsàsevere)
In one sentence, what is a dermatome?
An area of skin in which sensory nerves derive from a single spinal nerve root
Where does the dermatome project? Where can pain refer along a dermatome?
Projects more distally than the key muscle (myotome)
Dermatome and key muscles develop from the same segment
Any structure within a particular segment can refer pain to the same dermatome of that segment
It may refer along the whole length of the dermatome or only part of it
What is root pain? Is all root pain referred? Is all referred pain root pain?
Irritation of nerves and nerve roots
Deep, sharp and well localized
All root (radicular) pain is referred, but not all referred pain is root pain
What is acute pain? Give examples. What is its role?
Results from injury or disease that causes, or can cause, tissue damage
E.g., infection, trauma, metabolic disorder progression, degenerative disease
Protects against further tissue damage
- Results from injury or disease that causes, or can cause, tissue damage
- E.g., infection, trauma, metabolic disorder progression, degenerative disease
- Protects against further tissue damage.
What kind of pain is this?
Acute pain
What is subacute pain? What is its purpose?
Similar to acute pain occurring later in the process
Continues to protect against damage
- Similar to acute pain occurring later in the process
- Continues to protect against damage.
What kind of pain is this?
Subacute pain.
What is chronic pain? What is it associated with? Does it have a role?
Persists beyond the normal time expected for healing of injured tissue
Associated with structural and functional changes in the central nervous system
No longer a symptom or protective
- Persists beyond the normal time expected for healing of injured tissue
- Associated with structural and functional changes in the central nervous system
- No longer a symptom or protective.
What kind if pain is this?
Chronic
Give two kinds of stimulus or source of pain, and one example for each.
Chemical Sources
• Substances that are released with tissue injury (space occupying)
Mechanical Sources
- Normal Stress on Abnormal Tissue
- Ex: movement with a patient just out of a cast
- Abnormal Stress on Normal Tissue
- Not necessary for pathology to be present for pain to be produced
•Ex: bend finger back and hold it
How can upregulation and sensitization happend?
- Nociceptive system is usually very quiet
- When injury activates the system, a relatively innocuous stimuli can trigger pain perception
- Events that were not painful before become painful
What is nociceptive pain? What are its characteristics?
Nociceptive pain: normal pain response
• Usually aching or throbbing and well-localized, time limited (resolved once the tissue heals), responds well to analgesics
What is neuropathic pain? What are its characteristics?
- Neuropathic pain: nerve damage (e.g., abnormal firing, increased signal to brain). It is a direct consequence of a lesion or disease affecting the somatosensory system
- Tingling, shock-like or burning pain, usually chronic and responds poorly to conventional analgesics
What is hyperalgesia?
Hyperalgesia: increased pain from a stimulus that normally provokes pain
What is allodynia?
Allodynia: pain due to stimulus that does not normally provoke pain
What could cause neuropathic pain? Explain and give examples.
May result from various causes that affect the brain, spinal cord and peripheral nerves, including:
• Complex Regional Pain Syndrome (II)
- Diabetic Neuropathy
- Phantom Limb Pain
- Post-Stroke
Often experienced in parts of the body that otherwise appear normal
Generally chronic, severe and resistant to over-the-counter analgesics
How could neuropathic pain be desribed by the patient?
Pain may be spontaneous or evoked (e.g., allodynia, hyperalgesia, hyperpathia)
The quality of the pain is described as burning, electric shock, shooting and dysesthesia
**Often the stimulus/response relationship is unclear
Name the three known mechanisms for neuropathic pain
Known mechanisms include:
- Ectopic impulse generation
- Response to activity in adjacent nerves
- Changes in sensitivity
Describe peripheral sensitization. What are the three ways in which the increase could happend?
- Increased afferent nociceptor input to the CNS. Peripheral sensitization causes the amount of pain that you feel to be out of proportion to the extent of your injury
- Increasing pain signals that could occur through:
- Spontaneous firing, not requiring a signal• An easier threshold to reach
- Increased firing frequency
In peripheral sensitization, what is the role of the chemical mediators after a trauma?
Trauma
Inflammatory Response
Chemical Influence on Afferent Neuron Impulse
Describe the reduced reponse threshold pathway of peripheral sensitization.
- Chemicals released in response to tissue trauma will bind to ion channels in the membrane to alter permeability and excitability
- Indirect influence through 2nd messenger system
- (altered pH of the tissue)
- Inhibition of after-hyperpolarization
What is central sensitization? What is it initiated by?
- An aspect of neuroplasticity (i.e., brain changes with experience)
- Describes the changes at the cellular level which support neuroplastic changes in
- • Spinal cord
- • Supraspinal centres
• Initiated by high activity levels the in peripheral nociceptors leading to activity- dependent increases in excitability of nerves in the spinal cord
What are the two mechanisms of central sensitization called?
Chemical property changes
Neuroanatomical reorganization
Why as clinicians should we be aware of sensitization?
BAD NEWS
- The nervous system changes in response to pain
- It becomes more sensitive to pain
- What may be considered “excessive” pain behaviours may actually reflect sensitization of the nociceptive system
GOOD NEWS
• The nervous system changes in response to experience or intervention
What are the purposes of pain assessment?
- Diagnosis
- Prognosis
- Track changes over time (numeric rating scale)
- Assist in clinical decision making – quality and type of pain to determine Rx
What are some things you could be looking for during a pain history assessment?
Pain Characteristics – onset, duration, location, quality, intensity, associated symptoms, exacerbating and relieving factors [OPEN ENDED QUESTIONS!]
Past and current management therapies
Relevant medical and family history
Psychosocial history
Impact of pain on daily life – work, daily activities, personal relationships, sleep,
appetite, emotional state
Patient (and family’s) expected goals for treatment
- ASK the patient about their pain (consider the ICF model)
- Asking about ADL’s and IADL’s
- Asking about physical activity, mood, sleep, appetite, energy level
- Identify THE PATIENT’S preferred pain terminology
- Hurting, aching, stabbing, discomfort, soreness
- Use a pain scale that works for the individual
- Insure understanding of its use
- Modify sensory deficits
