Pain Mechanism and Management Flashcards
Define acute pain
an unpleasant sensory or emotional experience that is associated with actual or potential tissue damaging stimuli
what can pain be influenced by
- expectations
- significance
- emotions
- context in which it is experienced for example if you don’t know where it is it can be more frightening
Name two theories of pain
Specificity theory
Gate control theroy
describe specificity theory
This is the idea that a specific stimulus leads to a response and this allows su to experience pain
- there is a direct and autonomic linked between cause of pain and signal through spinal cord to brain receptors resulting in sensitisation
- ignores the effects of emotion and pain, attention and distraction, and the individuals meaning of pain
Describe gate control theory
when the gate is open in the spinal cord pain is experienced whereas if the gate is closed in the spinal cord that there is no pain
- idea that pain is a perception rather than a sensation
- most pain has peripheral, spinal and brain based controls and there is individual variation
describe how gate control theory works
Gate open
- noxious stimulus activates pain control fibres A delta and C fibres
- these input into the spinal cord
- signals from the brain such as tension, depression, boredom and focus on pain inputs into the spinal cord as well
- these both leads to transmission up to the brain which leads to the feeling of pain
Gate closed
- stimulate pain fibres C and A delta
- this is inhibited by analgesia medication
- can also inhibit this by counter-stimulation for example by rubbing, TENS and acupuncture which activates other perisperhal fibres
- these inhibit input from the brain as well
- therefore the transmission cells are inactive
where is the gate located in gate control theroy
spinal cord
What is counter stimulation
- can also inhibit this by counter-stimulation for example by rubbing, TENS and acupuncture which activates other perisperhal fibres
what is a TENS machine
- this is an electrical stimulation machine
what is the most common cause of chronic pain
- arthritis
name some facts of chronic pain
25% of adults
- up to two years to gain adequate control
- 20% lose a job
- 20% with major depressive disorder
- 15% report wish to die
- 21% of suicide attempts are patients being managed for chronic pain
define chronic pain
- A continued state of suffering, pain persists past the healing phase following an injury
What are the three main areas in the brain that are important in chronic pain
- Sensory/discrimitive pain – localisation in time and space, assessment of intestine, lateral system, lateral thalamic nuclei S1, S2, SMA
- Affective/motivational – emotional/unpleasant aspects, reward in escape, medial system (HG medial thalamic nuclei, ACC, insula)
- Cogntivie/evaluative – interpretation of pain and its meaning, cogntivie system (ACC DLPC)
What does pain involve and what does this allow for
Pain is an integrated constructive that involves
- Sensory
- Emotional and motivational
- Cogntivie and evaluative
This allows for
- Threat assessment and memory of pain
- Repetition of behaviour
What is the most common mental disorder associated with pain
MDD (major depressive disorder/clinical depression) is the most common mental disorder associated with pain
what does pain do to MDD
Pain intensity increases with MDD severity
Describe how pain and MDD are linked
MDD can result in chronically painful symptoms while chronically painful symptoms can also result in MDD
name the neurotransmitters that are involved in chronic pain
- Serotonin
- Noradrenaline
- Dopamine
- Opioid system
- Dysfunction in 1 or more of these circuits results in chronic pain/MDD and anxiety
what do - - Serotonin - Noradrenaline - Dopamine - Opioid system do that results in a decrease in pain/MDD
- Serotonin = surpasses sensation of normal bodily functions
- Noradrenaline = surpasses sensation of normal bodily functions
- Dopamine = salience - this is the perceptual quality by which an observable thing stands out relative to its environment
- Opioid system = prevents spread of pain, dampens pain, reinforces behaviour
what 3 systems are linked
- Pain, MDD and anxiety these may reflect disturbances in multiple systems
What are the 4 types of pain behaviours and give examples
Negative effect - bad mood, irritability, upset
Facial/audible expression of distress - gritting teeth, moaning
Distorted ambulation or posture - limping, stooping, holding affected area
Avoidance of activity - lying down, staying home from work, avoiding physical activity
describe pain and addiction
- Aberrant drug related behaviours is 11.5
What is addiction associated with
Addiction is associated with changes in
- Serotonin – mood is stimulated
- Noradrenaline – mood is stimulated
- Dopamine – salience – importance- increased likelihood of repetition
- Opioid systems – reinforces the behaviour through pleasure
- Entry into the circuit can be direct and from either side
Describe how cognitive behaviour therapy works
cognitive techniques
- distraction - focusing on a non painful stimulus
- non pain imagery - focusing on mental scenes unrelated to pain
- pain redefinition - replace feeling of threat with realistic thoughts about the pain experience and capacity to cope
Behavioural techniques
- medication scheduling - removes medicating as pain behaviour, reduces reliance on medication
- behaviour reinforcement - discourages sick-role behaviour, reduces the disability that accompanies chronic pain and increases the activity levels
Name some other psychological pain control methods
- Biofeedback – provides biophysiological feedback to patient about some bodily process the patient is unware of
- Relaxation – systemic relaxation of the large muscle groups
- Hypnosis – relaxation and suggestion and distraction and altering the menaing of pain
Name the centrally acting agents used for pain control
Antidepressants (tricyclics, e.g. amitriptylline), 5HT
Antipsychotics - works in similar way to antidepressants but often more sedating
Mood stabilisers - special circumstances
How do you manage pain
- Aggressive pharmacotherapy optimisation (monitoring, increasing dose or switching)
- Weaning of opiates
- 12 week CBT programme
- Follow up – increase dose, switch, new CBT approaches
