Pain and Central Sensitisation Flashcards
What does pain mean?
- Danger signal to protect ourselves
What is meant by maladaptive pain?
- Where the initial stimulus for the pain is no longer present but pain still persists
What are two examples of maladaptive pain?
- Fibromyalgia
- Osteoarthritis
What is inflammatory pain a result of?
- ## Break in the skin, damage to the joints or gastric erosion in joints leading to release of inflammatory mediators
What do damaged tissue and inflammatory cells release?
- Release chemical mediators creating an inflammatory soup
What are some examples of chemicals released?
-Histamine
-Serotonin
-Prostaglandins
-ATP
Hydrogen ions
-Nerve growth factor
What do the chemicals do when they have been released?
- bind to their respective receptors
- activating neural ascending pathways
- sending signal through the dorsal route ganglion, up the neural ascending pathways to the brain
- Pain stimulus activated in brain
What are two examples of pain treatment options?
- Cox2 inhibitors
- Opioids
What are Nociceptors?
-Pain receptors
What happens during a painful stimulus?
- Painful stimulus activates nociceptor
- Primary sensory neuron enters spinal cord and diverges
- One collateral activates ascending pathway for sensation and postural adjustment
- Withdrawal reflex pulls foot away from painful stimulus
- Crossed extensor reflex supports body as weight shifts away from painful stimulus
What is neuropathic pain?
- neuropathic pain is pain that is a result of ongoing activation of the central nervous system
What are some examples of causes of neuropathic pain?
- Surgery
- Chemotherapy
- Disease process
- Neurotoxicity
- Trauma
- Nerve compression
- Genetic predisposition
What is common with people who have OA?
- Have radiographic changes in 80% of people aged above 75
What are the environmental risks that could lead to OA?
- Obesity
- Biomechanics (previous injury such as torn acl)
- Meniscectomy ( surgery of the knee )
What are the genetic factors for OA?
- More common with females
- Family History
What psychological factors for OA?
- Depression
- Anxiety
What are examples of sociocultural factors that cause OA related pain?
- Being overweight
- Social class
- Unemployment
What is joint pathology?
- Extent of damage to a joint
What is synovitis?
- inflammation of nerves and blood supply near a joint.
What is injurious load in the context of OA pain?
- placing increased load onto joints without sufficient protection
How does OA-related knee pain differ?
- Knee pain patterns differ by stage of disease
- Early stages: intermittent activity related pain
- Later stages: pain becomes more persistent, even when resting
How often does pain persist in patients who have had knee replacements?
- 20-30% of patients
What is the pathology of OA?
- Sustained mechanical and inflammatory stimuli in the joint may lead to peripheral sensitization.
- Leads to constant activation of nociceptors around the joint
- Leads to activation of pain signal which is sent up the dorsal route ganglion and activating the ascending pathways in the cortex and the thalamus
What is found in the descending inhibitory pathway in the people who experience chronic pain?
-The descending pathway is not fully functioning/working
What is central sensitisation?
- concept that although peripheral signal that initially triggers sensitization
- CNS amplifies pain pathway
What is noticed in patients with OA?
- Heightened pain sensitivity
- Inadequate descending modulation
What are 3 clinical clues?
- Allodynia
- Hyperalgesia
- Radiating pain
What is allodynia?
- Pain or movements in locations that should not be painful
What is hyperalgesia?
- Enhanced pain in structures that should be painful
What is radiating pain?
- Pain that is felt in places other than damaged area
