Anaesthetics - Essential Pain Management Flashcards
what is the definition of pain?
Pain is “an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage, or described in terms of such damage”
Six Key notes in latest revision of pain definition 2020, what are they?
- Pain is a personal experience influence by biological, psychological and social factors
- Pain and nociception are different phenomena
- Individuals learn the concept of pain through life experiences
- A person’s report of pain should be respected
- Pain serves an adaptive role but may have adverse effects on function and psychological well being
- Verbal description is only one of several behaviours to express pain
why should we bother to treat pain?
- 1 in 4 people live with persistent pain
- Basic Human Right
- 66% of people attending A & E seeking help with pain had made around 3 visits to HCP in proceeding weeks
- Person living with pain has poor quality of life as bad as other neurological diseases
- Low Back Pain is the number 1 disease for years lost to disability worldwide
what are the physical benefits to the patient of treating pain?
- Improved sleep, better appetite
- Fewer medical complications (e.g. heart attack, pneumonia)
what are the phycological benefits of treating pain for a patient?
- Reduced suffering
- Less depression, anxiety
what are the befits of treating pain for the family?
Improved functioning as a family member (e.g. as a father or mother)
Able to keep working
whata re the benefits of treating pain for society?
lower health costs (e.g. shorter hospital stay)
able ot contribute to the community
Classification of pain:
whata r ethe different classifications of pain in relation to duration?
Acute
Chronic
Acute on chronic
Classification of pain:
what ar ethe different classifications of pain in relation ot the cause?
cancer
non-cancer
Classification of pain:
what are the different classifications of pain in regards to the mechanism? (maybe ht emost useful classification)
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 cause
what is cancer pain like?
Progressive
May be mixture of acute and chronic
what is non-cancer pain like?
Many different causes
Acute or chronic
what is nociceptive pain?
obvious tissue injury or illness
Also called physiological or inflammatory pain
serves a protective function
Description of the pain may be sharp +/- dull and also weill be well localised
what is neuropathic pain?
- Nervous system damage or abnormality
- Tissue injury may not be obvious (Pain going on long after the original injury if there is an injury at all)
- Does not have a protective function
- Description:
- Burning, shooting ± numbness, pins and needles
- Not well localised
the physiology of pain is made up by 4 steps, what are they?
Periphery
Spinal cord
Brain
Modulation (a descending pathway to switch of the pain pathway into the dorsal horn)
4 basic steps that result in the experience of pain for the patient
as part of the physiology of pain, the first step is the periphary, what happens here to start the pathway of pain?
- 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 (Dorsal route ganglion of the spinal cord)
as part of the physiology of pain, the second step is the spinal cord, how is it involved in this pathway?
- 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
spinothalamic tract
as part of the physiology of pain, the third step is the brain, how is it involved in this pathway?
- Thalamus is the second relay station
- Connections to many parts of the brain
- Cortex
- Limbic system
- Brainstem
•Pain perception occurs in the cortex
as part of the physiology of pain, the fourth step is the modulation, how is it involved in this pathway?
- Descending pathway from brain to dorsal horn
- Usually decreases pain signal
Done through many different types of neurotransmitters
one type of modulation is the gate theory, what is it?
Rubbing or massaging activated an inhibiting neurone to switch of the nociceptive afferent signal from going into the dorsal horn
what is the cause of neuropathic pain an dhow does it need to be treated?
- Abnormal processing of pain signal
- Nervous system damage or dysfunction
- Needs to be treated differently (from nociceptive pain)
- Examples:
- Nerve trauma, diabetic pain (damage – ischemic damage)
- Fibromyalgia, chronic tension headache (dysfunction)
what is the pathological mechanisms of neuropathic pain?
- Increased receptor numbers (enhance pain signal and keeps it going for longer)
- Abnormal sensitisation of nerves
- Peripheral
- Central
- Chemical changes in the dorsal horn
- Loss of normal inhibitory modulation (from descending pathways)
what are the main drug classifications and examples of each?
•Simple analgesics:
- Paracetamol (acetaminophen)
- Non-Steroidal Anti-inflammatory drugs - Diclofenac, Ibuprofen
•Opioids:
- Weak: Codeine, Dihydrocodeine, Tramadol
- Strong: Morphine, Oxycodone, Fentanyl
(Note that both weak and strong opioids have the potential for addiction)
whata re some otehr analgesics?
- Tramadol (Mixed opiate and 5HT/NA reuptake inhibitor)
- Antidepressants (e.g. amitriptyline, duloxetine)
- Anticonvulsants (e.g. gabapentin)
- Ketamine (NMDA Receptor antagonist)
- Local anaesthetics
- Topical agents (e.g. Capsaicin)
what are some treatments that can be used to affect the periphery?
- Non-drug treatments - Rest, ice, elevation
- Non-steroidal Anti-inflammatory drugs
- Local anaesthetics