Anaesthetics: Essential Pain Management Flashcards
What is pain?
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
What are the physical benefits for the patient if we treat pain?
- Improved sleep, better appetite
- Fewer medical complications (e.g. heart attack, pneumonia)
What are the psychological benefits for the patient if we treat pain?
- Reduced suffering
- Less depression, anxiety
What are the benefits for the family if we treat pain?
- Improved functioning as a family member (e.g. as a father or mother)
- Able to keep working
What are the benefits for society if we treat pain?
- Lower health costs (e.g. hospital stay)
- Able to contribute to the community
How can pain be classified?
- Duration
- Acute
- Chronic Cause
- Cancer / Non-cancer
- Mechanism
- Nociceptive
- Neuropathic
Describe nociceptive pain
- Sharp +/- dull
- Well localised
When does nociceptive pain occur?
When there is obvious tissue injury or illness
What is the function of nociceptive pain?
It has a protective function and is also referred to as inflammatory pain
When does neuropathic pain occur?
When there is nervous system damage or abnormality
Describe neuropathic pain
- Burning, shooting +/- paraesthesia
- Not well localised
- Does not have a protective function
What are the 4 steps in the physiology of pain?
- Periphery
- Spinal cord
- Brain
- Modulation
What physiology occurs in the periphery during the pain response?
- Tissue injury
- Release of chemicals e.g. prostaglandins, substance P
- Stimulation of pain receptors (nociceptors)
- Signal travels in Aδ or C nerve to spinal cord
What physiology occurs in the spinal cord during the pain response?
- Dorsal horn is the first relay station
- Aδ or C nerve synapses with second nerve
- Second nerve travels up contralateral side of spinal cord
What physiology occurs in the brain during the pain response?
- Thalamus is the second relay station
- Connections to many parts of the brain including cortex, limbic system and brainstem
- Pain perception occurs in the cortex
What physiology occurs during modulation in the pain response?
- Descending pathway from brain to dorsal horn
- Usually decreases pain signal
What is the gate theory?
Stimulation by non-noxious input is able to suppress pain by closing the ‘gate’ to painful input preventing pain sensation from travelling to the cortex
Give examples of neuropathic pain
- Nerve trauma, diabetic pain (damage)
- Fibromyalgia, chronic tension headache (dysfunction)
What is the pathology behind neuropathic pain?
- Increased receptor numbers
- Abnormal sensitisation of nerves (peripheral and central)
- Chemical changes in the dorsal horn
- Loss of normal inhibitory modulation
What non-drug treatments can be used to act at the periphery?
- Rest
- Ice
- Compression
- Elevation
What drugs can be used to act at the periphery?
- NSAIDs
- Local anaesthetics
What non-drug treatments can be used to act at the spinal cord?
- Acupuncture
- Massage
- TENS
What drugs can be used to act at the spinal cord?
- Local anaesthetics
- Opioids
- Ketamine
What non-drug treatment can be used to act at the brain?
Psychological therapies
