Essential Pain Management Flashcards
1
Q
What is pain?
A
Pain = unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage
2
Q
What are the benefits of treating pain?
A
- Patient
- Physical
- Improved sleep
- Better appetite
- Fewer medical complications such as heart attack
- Psychologically
- Reduced suffering
- Less depression and anxiety
- Physical
- Family
- Improved functioning as family member
- Able to keep working
- Society
- Lower health costs
- Contribute to community
3
Q
How can pain be classified?
A
4
Q
Describe acute and chronic pain?
A
- Acute
- Pain of recent onset and limited duration
- Chronic
- Pain lasting > 3 months
- Pain lasting after normal healing
- Often no identifiable cause
5
Q
Describe cancer and non-cancer pain?
A
- Cancer pain
- Progressive
- May be mixture of acute and chronic
- Non-cancer pain
- Many different causes
- Acute or chronic
6
Q
What is nociceptive pain?
A
- Obvious tissue injury or illness
- Also called physiological or inflammatory pain
- Protective function
- Description
- Sharp +/- dull
- Well localised
7
Q
What is nociceptive pain also called?
A
- Also called physiological or inflammatory pain
8
Q
What function does nociceptive pain have?
A
- Protective function
9
Q
What would the patient complain of with nociceptive pain?
A
- Sharp +/- dull
- Well localised
10
Q
What is neuropathic pain?
A
- Nervous system damage or abnormality
- Tissue injury may not be obvious
- Does not have protective function
- Description
- Burning, shooting +/- numbness, pins and needles
- Not well localised
11
Q
How would a patient describe neuropathic pain?
A
- Burning, shooting +/- numbness, pins and needles
- Not well localised
12
Q
Describe the 4 steps in pain physiology resulting in the experience of pain?
A
- Periphery injury
- Tissue injury causes release of chemicals such as prostaglandins, substance P
- Stimulation of pain receptors (nociceptors)
- Signals travel in Aδ or C nerve to spinal cord
- Signals into spinal cord through dorsal route ganglion
- Dorsal horn is first relay station
- Aδ or C nerve synapses with second nerve
- Travels up opposite side of spinal cord (usually spinothalamic tract) into thalamus
- Ascending pathway to brain (thalamus) through dorsal horn
- Thalamus is second relay station
- Connections to many different parts of brain – cortex, limbic system and brainstem (connections go both ways)
- Pain perception occurs in cortex
- Modulation is descending pathway through dorsal horn to turn of pain
- Descending pathway from brain to dorsal horn to decrease pain signal
- Done using many different types of neurotransmitters
- Most important way of modulation is known as “gate theory of pain”
- Rubbing, massaging or application of heat stimulates large Aa/AB fibres that activates inhibitory neuron that switches off nociceptive afferent signal from going into dorsal horn
13
Q
What is released in tissue injury, where does it act and what does this cause?
A
- Tissue injury causes release of chemicals such as prostaglandins, substance P
- Stimulation of pain receptors (nociceptors)
- Signals travel in Aδ or C nerve to spinal cord
14
Q
In what class of nerve fibres does pain travel?
A
- Signals travel in Aδ or C nerve to spinal cord
15
Q
What is the first relay station of pain?
A
Dorsal horn
16
Q
Does pain signal travel up contra or ipsilateral side of spinal cord?
A
Contralateral (usually in spinothalamic tract)
17
Q
In what spinal tract does pain normally travel up the spinal cord?
A
Spinothalamic tract
18
Q
What is the second relay station of pain?
A
Thalamus
19
Q
After the thalamus where does pain perception travel? Where does pain perception occur?
A
- Connections to many different parts of brain – cortex, limbic system and brainstem (connections go both ways)
- Pain perception occurs in cortex
20
Q
What is modulation?
A
- Descending pathway from brain to dorsal horn to decrease pain signal
- Done using many different types of neurotransmitters
- Most important way of modulation is known as “gate theory of pain”
- Rubbing, massaging or application of heat stimulates large Aa/AB fibres that activates inhibitory neuron that switches off nociceptive afferent signal from going into dorsal horn
21
Q
Describe gate theory of pain?
A
- Rubbing, massaging or application of heat stimulates large Aa/AB fibres that activates inhibitory neuron that switches off nociceptive afferent signal from going into dorsal horn
22
Q
What does neuropathic pain occur due to?
A
- Due to nervous system damage or dysfunction
23
Q
What are examples of neuropathic pain?
A
- Fibromyalgia, chronic tension headache (dysfunction)
24
Q
Describe the pathological mechanisms that can cause neuropathic pain?
A
- Increased receptor numbers
- Abnormal sensitisation of nerves
- Peripheral
- Central
- Chemical changes in dorsal horn
- Loss of normal inhibitory modulation
25
What are the different drug classifications for pain management?
* **Simple analgesics**
* Paracetamol (acetaminophen)
* Good for mild pain (by itself) or moderate-severe pain (with other drugs)
* Advantages – cheap, safe, many administration routes
* Disadvantage – liver damage in OD
* Non-steroidal anti-inflammatory drugs
* Such as iclofenac, ibuprofen, aspirin
* Good for nociceptive pain, best with paracetamol (synergism)
* Advantages – cheap, generally safe
* Disadvantages – GI side effects, reduced renal blood flow, bronchospasm in some patients with asthma
* **Opioids**
* Weak
* Codeine
* Good for mild-moderate acute nociceptive pain, best with regular paracetamol
* Advantages – cheap, safe
* Disadvantages – constipation, not good for neuropathic pain
* Dihydrocodeine
* Tramadol
* Weak opioids effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
* Advantages – less respiratory depression, can be used with opioids and simple analgesics, less constipation than opioids
* Disadvantages – nausea and vomiting, controlled drug
* Strong
* Morphine
* Good for mod-severe nociceptive pain and cancer pain, not adviced for neuropathic pain
* Advantages – cheap, safe, many routes of administration
* Disadvantages – constipation, respiratory depression in high doses, addition and avoidance due to fear of addiction, controlled drug
* Oxycodone
* Fentanyl
* Both weak and strong have potential for addiction
* **Other**
* Tramadol
* Mixed opiate and 5HT/NA reuptake inhibitor
* Antidepressants
* Amitriptyline
* Tricyclic antidepressant (TCA)
* Increases descending inhibitory signals
* Good for neuropathic pain, also treats depression and poor sleep
* Advantages – cheap, safe in low doses
* Disadvantages – anti-cholinergic side effects (glaucoma, urinary retention), long term use might be linked with cognitive decline and dementia
* Duloxetine
* Anticonvulsants (also called membrane stabilisers)
* Good for neuropathic pain
* Carbamazepine
* Sodium valproate
* Gabapentin
* Ketamine
* NMDA receptor antagonist
* Local anaesthetics
* Topical agents
* Such as capsaicin
26
What are examples of simple analgesics?
* **Paracetamol (acetaminophen)**
* Good for mild pain (by itself) or moderate-severe pain (with other drugs)
* Advantages – cheap, safe, many administration routes
* Disadvantage – liver damage in OD
* **Non-steroidal anti-inflammatory drugs**
* Such as iclofenac, ibuprofen, aspirin
* Good for nociceptive pain, best with paracetamol (synergism)
* Advantages – cheap, generally safe
* Disadvantages – GI side effects, reduced renal blood flow, bronchospasm in some patients with asthma
27
For paracetomol:
- indications
- advantages
- disadvantages
* Good for mild pain (by itself) or moderate-severe pain (with other drugs)
* Advantages – cheap, safe, many administration routes
* Disadvantage – liver damage in OD
28
For NSAIDs:
- drugs
- indications
- advantages
- disadvantages
* Such as iclofenac, ibuprofen, aspirin
* Good for nociceptive pain, best with paracetamol (synergism)
* Advantages – cheap, generally safe
* Disadvantages – GI side effects, reduced renal blood flow, bronchospasm in some patients with asthma
29
What are the 2 different classes of opiods?
* **Weak**
* Codeine
* Good for mild-moderate acute nociceptive pain, best with regular paracetamol
* Advantages – cheap, safe
* Disadvantages – constipation, not good for neuropathic pain
* Dihydrocodeine
* Tramadol
* Weak opioids effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
* Advantages – less respiratory depression, can be used with opioids and simple analgesics, less constipation than opioids
* Disadvantages – nausea and vomiting, controlled drug
* **Strong**
* Morphine
* Good for mod-severe nociceptive pain and cancer pain, not adviced for neuropathic pain
* Advantages – cheap, safe, many routes of administration
* Disadvantages – constipation, respiratory depression in high doses, addition and avoidance due to fear of addiction, controlled drug
* Oxycodone
* Fentanyl
* Both weak and strong have potential for addiction
30
What are examples of weak opiods?
* Weak
* **Codeine**
* Good for mild-moderate acute nociceptive pain, best with regular paracetamol
* Advantages – cheap, safe
* Disadvantages – constipation, not good for neuropathic pain
* **Dihydrocodeine**
* **Tramadol**
* Weak opioids effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
* Advantages – less respiratory depression, can be used with opioids and simple analgesics, less constipation than opioids
* Disadvantages – nausea and vomiting, controlled drug
* Strong
* Morphine
* Good for mod-severe nociceptive pain and cancer pain, not adviced for neuropathic pain
* Advantages – cheap, safe, many routes of administration
* Disadvantages – constipation, respiratory depression in high doses, addition and avoidance due to fear of addiction, controlled drug
* Oxycodone
* Fentanyl
* Both weak and strong have potential for addiction
31
What are examples of strong opiods?
* Weak
* Codeine
* Good for mild-moderate acute nociceptive pain, best with regular paracetamol
* Advantages – cheap, safe
* Disadvantages – constipation, not good for neuropathic pain
* Dihydrocodeine
* Tramadol
* Weak opioids effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
* Advantages – less respiratory depression, can be used with opioids and simple analgesics, less constipation than opioids
* Disadvantages – nausea and vomiting, controlled drug
* Strong
* **Morphine**
* Good for mod-severe nociceptive pain and cancer pain, not adviced for neuropathic pain
* Advantages – cheap, safe, many routes of administration
* Disadvantages – constipation, respiratory depression in high doses, addition and avoidance due to fear of addiction, controlled drug
* **Oxycodone**
* **Fentanyl**
* Both weak and strong have potential for addiction
32
For codeine:
- indications
- advantages
- disadvantages
* Good for mild-moderate acute nociceptive pain, best with regular paracetamol
* Advantages – cheap, safe
* Disadvantages – constipation, not good for neuropathic pain
33
For tramadol:
- mode of action
- advantages
- disadvantages
* Weak opioids effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
* Advantages – less respiratory depression, can be used with opioids and simple analgesics, less constipation than opioids
* Disadvantages – nausea and vomiting, controlled drug
34
For morphine:
- indications
- advantages
- disadvantages
* Good for mod-severe nociceptive pain and cancer pain, not adviced for neuropathic pain
* Advantages – cheap, safe, many routes of administration
* Disadvantages – constipation, respiratory depression in high doses, addition and avoidance due to fear of addiction, controlled drug
35
What are examples of pain management drugs that not simple analgesics of opiods?
* **Tramadol**
* Mixed opiate and 5HT/NA reuptake inhibitor
* **Antidepressants**
* Amitriptyline
* Tricyclic antidepressant (TCA)
* Increases descending inhibitory signals
* Good for neuropathic pain, also treats depression and poor sleep
* Advantages – cheap, safe in low doses
* Disadvantages – anti-cholinergic side effects (glaucoma, urinary retention), long term use might be linked with cognitive decline and dementia
* Duloxetine
* **Anticonvulsants (also called membrane stabilisers)**
* Good for neuropathic pain
* Carbamazepine
* Sodium valproate
* Gabapentin
* **Ketamine**
* NMDA receptor antagonist
* **Local anaesthetics**
* **Topical agents**
* Such as capsaicin
36
What class of drug is tramadol?
* Mixed opiate and 5HT/NA reuptake inhibitor
37
What are different antidepressants?
* **Amitriptyline**
* Tricyclic antidepressant (TCA)
* Increases descending inhibitory signals
* Good for neuropathic pain, also treats depression and poor sleep
* Advantages – cheap, safe in low doses
* Disadvantages – anti-cholinergic side effects (glaucoma, urinary retention), long term use might be linked with cognitive decline and dementia
* **Duloxetine**
38
What class of drug is amitriptyline?
* Tricyclic antidepressant (TCA)
39
For amitriptyline:
- mode of action
- indications
- advantages
- disadvantages
* Increases descending inhibitory signals
* Good for neuropathic pain, also treats depression and poor sleep
* Advantages – cheap, safe in low doses
* Disadvantages – anti-cholinergic side effects (glaucoma, urinary retention), long term use might be linked with cognitive decline and dementia
40
What are anticonvulsants also called?
Membrane stabilisers
41
For anticonvulsants:
- indication
- drugs
* Good for neuropathic pain
* Drugs
* Carbamazepine
* Sodium valproate
* Gabapentin
42
What is the mode of action of ketamine?
* NMDA receptor antagonist
43
What is an example of a topical agent used for pain management?
Capsaicin
44
What pain treatments target the periphery?
* Non-drug treatments like rest, ice, elevation
* NSAIDs to reduce prostaglandin and inflammatory soup
* Local anaesthetics
45
What pain treatments target the spinal cord?
* Non-drug treatments such as acupuncture, massage, TENS
* Local anaesthetics – epidural delivery or nerve blockade
* Opioids
* Ketamine
46
What pain treatments target the brain?
* Non drug treatments, psychological
* Drug treatments – paracetamol, opioids, amitriptyline, clonidine
47
What are examples of routes of administration?
* Oral
* Rectal
* Sublingual
* Subcutaneous
* Transdermal
* Intramuscular
* Intravenous – boluses, patient controlled systems or nurse administered
* Intrathecal/epidural
48
What are different delivery routes for local anaesthetics?
* Epidural (+/- opiates)
* Intrathecal (+/- opiates)
* Wound catheters
* Nerve plexus catheters
* Local infiltration of wounds
* Lidocaine patches for some neuropathic pain conditions
49
What can pain be assessed by?
* Verbal rating score (mild, moderate, severe, unbearable)
* Numerical rating score (smaller scales are better like 0-4 than 0-10)
* Visual analogue scale
* Smiling faces scale
* Abbey pain scale (for confused patients)
* Functional assessments
50
Describe the treatment of pain?
* Non-pharmacological
* Physical
* Rest, ice, elevation
* Surgery
* Acupuncture, massage, physiotherapy
* Psychological
* Explanation
* Reassurance
* Counselling
* Pharmacological
* Acute pain – WHO pain ladder
* Neuropathic pain – alternative analgesics, not responsive to WHO ladder drugs
51
What are examples of non-pharmacological treatments for pain?
* Physical
* Rest, ice, elevation
* Surgery
* Acupuncture, massage, physiotherapy
* Psychological
* Explanation
* Reassurance
* Counselling
52
What is the pharmacological treatment for acute and neuropathic pain?
* Acute pain – WHO pain ladder
* Neuropathic pain – alternative analgesics, not responsive to WHO ladder drugs
53
Describe the WHO pain ladder?
* Mild pain
* Start at bottom of pain ladder
* Moderate pain
* Bottom plus middle rung
* Severe
* Bottom plus
* REMEMBER – it is okay to start at top of ladder for severe/unbearable pain
* As pain resolves
* Move from top to middle, continuing bottom rungs drugs at all times
* Lastly stop NSAIDs first then paracetamol as more adverse effects with NSAIDs
54
What drugs are in steps 1, 2 and 3 of the WHO pain ladder?
55
Describe the 'RAT' approach to pain management?
* Recognise
* Ask and look for signs
* Assess
* Severity – pain score at rest and with movement, how is pain affecting patient
* Type – nociceptive or neuropathic, look for features of neuropathic like burning/shooting pain and phantom limb pain, other features like pins and needles or numbess
* Other factors – physical and psychological factors to make patients more susceptible to pain or more difficult to treat
* Treat
* Non-pharmacological
* RIE (rest, ice, elevation)
* Nursing care
* Surgery, acupuncture, message, TENS
* Psychological – explanation and reassurance
* Pharmacological
* WHO pain ladder, see above
* Not always useful, use other drugs early
* After RAT, reassess the patient to see if treatment is working and if any other treatment is needed
56
When assessing pain, as part of the 'RAT' approach, what should be considered?
* Severity – pain score at rest and with movement, how is pain affecting patient
* Type – nociceptive or neuropathic, look for features of neuropathic like burning/shooting pain and phantom limb pain, other features like pins and needles or numbess
* Other factors – physical and psychological factors to make patients more susceptible to pain or more difficult to treat
