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
What is acute pain?
Pain of recent onset and probable limited duration
What is chronic pain?
- Pain lasting for more than 3 months
- Pain lasting after normal healing
- Often no identifiable normal healing
Describe pain from cancer?
- Progressive
- May be a mixture of acute and chronic
Describe non-cancer pain
- Can have many different causes
- Can be acute or chronic
Describe nociceptive pain
- Sharp +/- dull
- Well localised
When does nociceptive pain occur?
When there is obvious tissue injury or illness
What does nociceptive pain function as?
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 +/- numbness, pins and needles
- Not well localised
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 (connects) with second nerve
- Second nerve travels up opposite 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 types of drugs can be used for the treatment of pain?
- Simple analgesics
- Opioids
- Other analgesics
