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?
What is a sulcus?
A groove in the brain
What is a gyrus?
A fold in the brain
what 2 sulci are important anatomical land marks?
- Central sulcus
- Lateral sulcus
What are these Gyri and what do they do?
What are these areas and what are there functions?
Broccas area = motor aspect of speach
Wernike’s area = language comrehension
What is this structure?
These parts make up the basal ganglia. Name them
What is this section of the brain called and what processes is it involved in?
The hippocampus
Involved in memory and learning
What is this part of the brain called and how can it be divided up?
The corpus callosum
It can be dived into the splenium (posterior), the body, the Genu (anterior), and the rostrum
Name these structures
What are the sensory and motor pathways in the spinal cord?
Dorsal column medial lemniscus = touch
Spinothalamic = pain
Corticospinal = motor control
What is the difference between ascending (sensory) and descending (motor) pathways in the brain?
Ascending pathways relay in the thalamus
Motor pathways bypass the thalamus
What fan like structure connects the cortex to the entrance/exit of the internal capsule?
The corona radiata
what structure lie just beneath the temporal love?
The insula cortex
Name these parts of the internal capsule
During embryological development, what do the dorsal and ventral horns grow from
Alar plate => Dorsal horn
Basal plate => Ventral horns
What is A-alpha fibres function?
Proprioceptors and motor nerves
What is A-Beta fibres function?
Mechanoreceptors of the skin (feel regular touch)
What is A-Delta fibre function?
Pain and temperature
What is the function of C fibres?
Temperature, pain itch
Where do afferent and efferent fibres leave/enter the spinal cord?
Dorsal horn = Afferent
Ventral horn = efferent
(DA VE)
name the white matter tracts in the spinal cord
- Dorsal funiculus
- Later Funiculus
- Ventral Funiculus
What is the venous supply of the spinal cord?
Baston venous plexus
Describe the arterial supply to the spinal cord
branches from the intercostal arteries form the radicular artery, which then branch into a anterior spinal artery and 2 posterior spinal arteries
what structure marks the end of the spinal cord?
The spinal cord ends at the conus medullaris and becomes the cauda equina
What is the role of the dorsal column medial lemniscus pathway, and describe its path through spinal cord
Discriminative touch
Afferent nerve reaches spinal cord and splits. One branch enters the dorsal root and the other travels up the spinal cord. It desiccates at the midbrain. then relays at the thalamus before entering the sensory cortex.
What is the role of the spinothalamic pathway and describe its pathway through the spinal cord.
Pain, Temperature, Crude touch
The enter the dorsal root horn and immediately synapses and desiccates before traveling up to the thalamus where it synapses again and goes onto the sensory cortex
Which pathway innervates the cranial nerves and describe its pathway?
corticobulbar pathway
Travels from the cortex to the cranial nerve nuclei
What is the role of the corticospinal pathway and describe its pathway through the spinal cord
Volountary motor control
Descends from the cortex to the medulla where 85% of fibres decussate.
What is the role of the reticulospinal pathway?
Involuntary control (posture/balance) of muscles
Pontine tracts = extensors
Medullary tract = Flexors
