Pain Flashcards
What are the benefits of treating pain?
Physical- improve sleep, better appetite
Psychological- reduce suffering, less depression and anxiety
For family- improve function as member of family, maintain employment
For society- reduced hospital stays so reduced cost, able to work
What are the different ways in which pain can be classified?
Duration- acute, chronic or acute on chronic
Cause- cancer or non-cancer
Mechanism- nociceptive or neuropathic
What is the difference between nociceptive and neuropathic pain?
Nociceptive- pain stimulus is directed into the pathway
Neuropathic- nerve damage
What are the characteristics of nociceptive pain?
Obvious tissue injury or illness
Also called physiological or inflammatory pain
Protective function
Described as sharp ± a dull aspect and well localized
What are the characteristics of neuropathic pain?
Nervous system damage or abnormality
Tissue injury may not be obvious
Does not have a protective function
Described as burning/shooting ± numbness/pins and needles. Not well localized
What are the four main steps in pain physiology?
Periphery
Spinal cord
Brain
Modulation
Describe the pain physiology processes in the periphery
Tissue injury
Release of chemicals- prostaglandins, substance P
Stimulation of nociceptors
Signal travels in Aδ or C nerve to spinal cord
Describe the pain physiology processes in the spinal cord
Dorsal horn is the first relay station
Aδ or C nerve synapses with second nerve
Second nerve travels up opposite side of spinal cord
Describe the pain physiology processes in the brain
Thalamus is the second relay station
Connections to many parts of the brain (cortex, limbic system, brainstem)
Pain perception occurs in the cortex
Describe the pain physiology processes in modulation
Descending pathway from brain to dorsal horn
Usually decreases pain signal
What are some examples of causes of neuropathic pain?
Nerve trauma
Diabetic pain
Fibromyalgia
Chronic tension headache
What pathological mechanisms can cause neuropathic pain?
Increased receptor numbers
Abnormal sensitisation of nerves (peripheral or central)
Chemical changes in the dorsal horn
Loss of normal inhibitory modulation
What are the drugs commonly used for pain?
Simples analgesics- paracetamol, NSAIDs (ibuprofen, diclofenac)
Opioids- codeine, dihydrocodeine, morphine oxycodone
Tramadol (mixed opiate and 5HT/NA reuptake inhibitor)
Nefopam (NMDA receptor antagonist, 5HT/NA reuptake inhibitor)
Antidepressants
Anticonvulsants
Ketamine
Local anaesthetics
Topical agents
What non-drug treatment can be used for pain originating from the periphery?
Rest
Ice
Compression
Elevation
What non-drug treatment can be used for pain originating from the spinal cord?
Acupuncture
Massage
TENS
What non-drug treatment can be used for pain originating from the brain?
Psychological
What drug treatment can be used for pain originating from the periphery?
NSAIDs
Local anaesthetic
What drug treatment can be used for pain originating from the spinal cord?
Local anaesthetic
Opioids
Ketamine
What drug treatment can be used for pain originating from the brain?
Paracetamol
Opioids
Amitriptyline
Clonidine
What are the advantages of paracetamol
Cheap
Safe
Can be given orally, rectally or IV
Good for mild pain in isolation or moderate to severe pain in conjunction with other drugs
What are the disadvantages of paracetamol
Liver damage in overdose
What are the advantages of NSAIDs
Cheap
Generally safe
Good for nociceptive pain
What are the disadvantages of NSAIDs
GI bleeds
Nephrotoxic
Can cause bronchospasm in sensitive asthmatics
What are the advantages of codeine
Cheap
Safe
Good for mild to moderate acute nociceptive pain
What are the disadvantages of codeine
Constipation
Not good for chronic pain
What are the advantages of tramadol
Less respiratory depression
Can be used with opioids and simple analgesics
What are the disadvantages of tramadol
Nausea and vomiting
Withdrawal possible
What are the advantages of morphine
Cheap Safe Can be given orally, IV, IM, SC Effective if given regularly Good for moderate to severe acute nociceptive pain or chronic cancer pain
What are the disadvantages of morphine
Constipation
Respiratory depression
Misunderstandings about addiction
Controlled drug
What are the advantages of amitriptyline
Cheap
Safe in low doses
Good for neuropathic pain
What are the disadvantages of amitriptyline
Anti-cholinergic side effects (glaucoma, urinary retention)
What are the advantages of anticonvulsants
Good for neuropathic pain
How do treatments of neuropathic and nociceptive pain differ?
Nociceptive pain management based on WHO pain ladder
Neuropathic pain manegement based on alternative analgesics (amitriptyline, gabapentin, duloxetine) and/or psychological and non-drug treatments
What are the steps in the RAT approach to pain?
Recognise
Assess
Treat
What steps should be taking when recognising pain?
Does the patient have pain? (Ask, look (frowning, moving easily, sweating?))
Do other people know the patient has pain? (Other health workers, patient’s family)
What steps should be taking when assessing pain?
Verbal Rating Score Numerical Rating Score Visual Analogue Scale Smiling faces Abbey Pain Scale (for confused patients) Functional Pain
Assess severity, type, characteristics and any other factors
What levels of pain corresponds to which steps of the WHO pain ladder?
Mild to moderate pain- step 1
Moderate to severe pain- step 2
Severe pain- step 3
What drugs are on each step of the WHO pain ladder?
Step 1- Non-opioids: aspirin, NSAIDs, paracetamol
Step 2- Mild opioids (codeine) with or without non-opioids
Step 3- Strong opioids (morphine)
Step 1 should be kept in conjunction with either step 2 or 3 but no need to keep step 2 when moved up to step 3
