Week 1 Flashcards
Define pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
What percentage of the population will experience chronic pain and severe chronic pain
Chronic pain = 20%
Severe chronic pain 3-5%
Define nociception
The natural mechanism by which an individual detects the presence of potentially tissue haeming stimulus
What are the steps of noiciception?
- Transduction (stimulus detected by nerve)
- Transmission (signal travels up nerve)
- Modulation (occurs in the spinal root)
- Perception
Where are nociceptors found?
In the skin, bones, muscles, internal organs, blood vessels.
They are not found in the brain
What types of nerve fibres are noicieptors?
Some Aß fibres (pain) and some C fibres (light touch & burning)
Explain pain gate control theory
C fibres carry pain signals to the ascending pain pathway. Inhibitory interneurons inhibit this signal to reduce the painful stimulus. Normal the C fibres inhibit the inhibitory interneurons, but Aß fibres can promote the inhibitory interneurons in the presence of touch/non painful stimulus.
This is why rubbing your knee after bumping it dulls the pain a little
How do TENS machines work to dull pain?
They activate Aß fibres which promote inhibitory interneurons, which inhibitory pain signals in the ascending pain pathways
Explain descending modulation of pain
The peri aqueducts grey matter (PAG) receive signals from all over the brain and send signals down a descending pathway to the dorsal horn to inhibit painful stimuli
What are the differences between neuropathic and nociceptive pain?
Neuropathic = nerve damage
Nociceptive = tissue damage
What are common descriptors are used to describe neuropathic pain?
Shooting
Burning
Tingling
Numbness
Electric shock - like
Describe the LANSS pain scale
It is used to assess/ differentiate neuropathic from nociceptive pain:
5 questions:
- prickling, tingling, pins and needles
- colour change in skin
- abnormally sensitive
- electric shocks
- burning
2 signs:
- pain due to cotton wool
- pin-prick threshold altered
Measured on scale of 24. A score over 12 usually indicates neuropathic pain
Differentiate somatic vs visceral pain
Somatic:
- Well defined location
- sharp/aching pain
- constant
Visceral:
- vague localisation
- dull/cramp pain
-periodic
Explain how herniated IVD can cause lower pack pain
A herniated disc can press on the afferent nerve root and/or the herniated disc can activate local nociceptors
What is radicular back pain?
Pain that begins in the back and radiates down the lower limbs in a narrow band (not the same as refferd pain)
How is pain clinically assessed?
History, physical examination and investigations.
Defining the characteristics (SOCRATES)
Explore the quality of life impacts and ideas/concerns/expectations
Describe the brief pain inventory (BPI)
The BPI assess the impact of pain on day to day activities like walking, sleep, socialising, mood
What are the 6 Ps of pain treatment
-prevention (care, excerise, stretching)
- pathology (splint, antibiotics, etc)
- physical therapies
- pharmacology
- procedural (local analgesia)
- psychological
What are the steps in the WHO analgesic ladder?
Step 1 - Non opiods (paracetamol & NSAIDs)
Step 2 - weak opiods (codeine, dihydrocodein)
Step 3 - strong opiods (morphine, fentanyl)
What are the side effects of opiods?
Sedation, constipation, insomnia, nausea, respiratory depression
What are the side effects of paracetamol?
Liver damage
What are the side effects of NSAIDs?
GI ulceration, bleeding, renal damage
What are the red flag symptoms of back pain?
- Weight loss
- fever
- anatomical change
- possible history of trauma
- cauda equivalent syndrome symptoms (incontinence, loss of sensation in leg/perineal area)
What are the 4 main lobes of the brain?
