What produces increased quantities of neuromodulators?
nociceptors A-delta and C-fibers
What are examples of NMs produced in centrally mediated hypersensitivity?
NMs produced in the centrally mediated hypersensitivity influence what?
characteristics of post synaptic membranes of CNS (first order sensory neurons are releasing more NM)
Due to convergence, the result is that the neurons in the pain pathway respond to what?
different types of innocuous input (mechanoreceptors) which is interpreted as noxious (painful)
Where are anatomical sites of central sensitization?
brain stem (reticular formation)
somatosensation and association cortices
If pt has experienced a major inflammatory or pathological event and still complains of pain following negative hematologic, blood chemistry, histological, radiographic and physical examinations, the pain may be due to:
hypersensitization of the CNS (may be basis of psychogenic pain)
Treatment of pain due to hypersensitization of the CNS falls into what 3 categories?
perception of a missing body part, which is no longer present. Most amputees experience a phantom limb
perception of chronic pain in an absent body part; usually manifests itself after surgical amputation
Where is phantom pain most common?
Where are common places of phantom pain beside the lower extremity?
nose, tongue, teeth, breasts, testes, penis, bladder, and anus
What are the theories of phantom pain?
there is no one well made theory
Neuroplasticity: some abnormalities may occur in set up
Hypersentization: due to loss of afferent input
How often does phantom pain occur?
may be continuous, intermittent, or random
What are attacks of phantom pain like?
often very severe
How do 25% of pts describe phantom pain?
burning, cramping, aching, crushing, stabbing, or shooting pain
What other disorders are the symptoms of phantom pain similar to?
peripheral nerve damage
Does everyone that experiences phantom limb experience phantom pain?
no, most people experience phantom limb, but not always phantom pain
What are some treatment strategies for phantom pain?
mirror reflection (decreases pain)
Physical: TENS, DCS
How does the CNS internally modulate pain?
under influence of pain or stress, certain neurons can release chemicals called opioid peptides which activate an opioid endogenous analgesic mechanism (system)
Where are opioids released?
Brain (amygdala, hypothalamus, medulla, periaqueductal gray region (PAG))
Spinal cord (dorsal horn)
What must occur in order to release opioid mediated analgesia system?
pain must be prolonged
could be due to psychological stress
How does the opioid mediated analgesia system work?
cell membranes of 2nd order spinothalamic tract contain opioid receptors
opiod binds to receptor on 2nd order neurons
binding causes 2nd order neurons to become hyperpolarized (harder to fire AP), so less noxious stimuli is transmitted
What happens when opioids are released?
causes hyperpolarization of neurons (inhibitory)
What type of analgesias are opioids?
centrally mediated analgesias
What does it mean that opioids are centrally mediated analgesias?
decrease noxious info going from neuron to neuron
What are opioids?
neuropeptides (protein molecules that affect the NS)
What are the 3 major chemical families of endogenous opioids?