Management of Chronic Pain Flashcards
What is pain?
An unpleasant sensory and emotional experience, associated with actual tissue damage or described in terms of such damage
What kind of experience is pain?
Unique and conscious
What are the 3 main variables in pain?
- Sociocultural
- Biological
- Psychological
What is obvious in acute pain?
Tissue damage
What type of function may acute pain have?
Protective
There is INCREASED nervous system activity in acute pain
TRUE
When does pain in acute pain resolve?
Upon healing
What is chronic pain?
Pain beyond expected period of healing
Describe chronic pain.
- Pain no longer serves a useful purpose
- Changes in pain signalling and detection
- Degrades health and function
What should you always use when taking a measurement of pain?
Verbal scale rating
What should you always look for in examination?
To see if the person is in pain
What kind of behavioural observations might you see in someone who is in pain?
- Grimacing
- Rigid body posture
- Limping
- Frowning
- Crying
What are some physiological responses to pain?
- Increased HR
* Increased BP
RULE 1
Listen to the patient
RULE 2
The pain is what they say it is
RULE 3
They can be in pain even if they don’t look like it
Name the 2 main types of pain.
- Nociceptive
* Neuropathic
Describe nociceptive pain.
An appropriate physiologic response to painful stimuli via an intact nervous system
Describe neuropathic pain.
An inappropriate response caused by a dysfunction in the nervous system
How is a diagnosis of neuropathic pain achieved?
History + Exam
How do patient usually describe neuropathic pain?
- Burning
- Shooting
- Tingling
- Sensitivity
On examination of a patient with neuropathic pain, what sensory changes are observed?
- Allodynia
* Hyperalgesia
What is allodynia?
Pain from a stimulus that isn’t normally painful
What is hyperalgesia?
More pain than expected from a painful stimulus ie. pin prick
Suggest some causes of neuropathic pain.
- Shingles, post-herpetic neuralgia.
- Surgery.
- Trauma.
- Diabetic neuropathy.
- Amputation.
- Many of unknown origin
What is neuroplasticity?
The ability of the nervous system to form and recognise synapses
What does a lower degree of chronicity relate to?
A better therapy result
Chronic pain is associated with MORPHOLOGICAL CHANGES IN THE CNS
TRUE
Once pain is present, it is often persistent and seldom totally resolves, even with treatment
TRUE
Give examples of non-opioid analgesics.
NSAID’s
Paracetamol
Give examples of opioid analgesics.
Tramadol.
Codeine.
Morphine.
Oxycodone.
Give examples of 2 antidepressants.
Amytriptyline
Duloxetine
Give examples of 2 anticonvulsants.
Gabapentin
Pregabalin
Give examples of 2 topical analgesics.
Capsaicin
Lidocaine 5% plaster
Topical analgesics reduce pain impulses transmitted by what?
- A delta fibres
* C fibres
What are the main side effects of topical analgesics?
- Rash
- Pruritus
- Erythema
List the main side effects of opioids.
- N+V
- Constipation
- Dizziness
- Vertigo
- Somnolence
- Dry skin
- Pruritus
List the main side effects of NSAID’s.
- GI irritation/bleeding
- Renal toxicity
- Drug-drug interactions
- CVS side effects
List the main side effects of anti-convulsants.
- Sedation
- Dizziness
- Ataxia
- Peripheral oedema
- Nausea
- Weight gain
List the main side effects of SNRI’s.
- N+V
- Constipation
- Somnolence
- Dry mouth
- Increased sweating
- Loss of appetite
Severe chronic pain is ________
MULTIFACTORIAL
What kind of pain do NSAID’s work on?
Nociceptive
What is the mod of action of NSAID’s?
- Inhibition of cyclooxygenase
* Prosatglandin synthesis decreases
Name some NSAID’s.
- Ibuprofen
* Aspirin
What is paracetamol a derivative of?
Analine derivative ie. Panadol
What is the efficacy of paracetamol?
- Analgesic
* Antipyretic
What is the mode of action of paracetamol?
- Inhibition of central prostaglandin synthesis
Give 2 examples of week opioids.
- Tramadol
* Codeine
Give 2 examples of strong opioids.
- Morphine
* Oxycodone
Describe the efficacy of opioids.
- For nociceptive pain
- Less effective in chronic states
- Only partially effective in neuropathic pain
Describe the mode of action of opioids.
- Activates the endogenous analgesic system
- Stimulate receptors in the limbic system to eliminate
the subjective feeling pain - Affect descending pathways that modulate pain perception
- Reduce ascending pain signal transmission in the spinal cord
Give 2 examples of antidepressants.
- Amitriptyline
* Imipramine
Describe the efficacy of antidepressants.
- Neuropathic pain
- Complex regional pain syndrome
- Tension headache
Describe the mode of action of antidepressants.
Inhibition of neuronal re-uptake of noradrenaline and/or serotonin (5-HT)
Give 2 examples of Selective Serotonin and Noradrenaline Reuptake Inhibitors (SSRIs +SNRIs).
- Duloxetine.
* Venlafaxine.
Under what category do Selective Serotonin and Noradrenaline Reuptake Inhibitors (SSRIs +SNRIs) come?
Antidepressants
Describe the efficacy of SSRI’s and SNRI’s.
- Neuropathic pain
SSRI’s are better than SRNI’s
FALSE - SNRI’s are better
Describe the mode of action of SSRI’s and SRNI’s.
- Selectively inhibit reuptake of noradrenaline +/- serotonin
- Provide analgesia by intensifying descending inhibition
Give 3 examples of anticonvulsants.
- Carbamazepine.
- Gabapentin.
- Pregabalin.
Describe the efficacy of anticonvulsants.
- Neuropathic pain
Describe the mode of action of anticonvulsants.
Different modes of action:
• Gabapentin: binds to presynaptic voltage-dependent calcium channels1
• Pregabalin: interacts with special N-type calcium channels1
• Carbamazepine: blocks Na+1 and Ca2+ channels
