Pain Flashcards
A sign that causes an excessive discharge of stimuli
Pain
Pain is both a
sensation and emotion
When can pain transmission occur?
When one has an intact spinothalamic system
A gate that receives pain stimuli from receptors
Substantia Gelatinosa
Transmitters of pain (excitatory)
Substance P
Calcium
Enzymes: Histamine
Prostaglandins
Inhibitory neurotransmitters of pain
Serotonin
GABA
Opioid peptides
Endorphins
Enkephalin
Dynorphin
What inhibitory neurotransmitter inhibits at the dorsal horn?
Opioid peptides
Pain pathway and interconnections
Receptors
Substantia Gelatinosa
Spinothalamic tract
Lateral/Anterior White mater
Tegmentum
VPL
Primary sensory area
subserve
the emotional aspect
of pain at the level of the brainstem
Spinoreticular pathway
Spinoreticular pathway
Pain to reticular fromation
To midbrain and pons tegmentum
to the hypothalamus
to the amygdala
Where is the Periaqueductal Gray (PAG) located?
gray matter of the tegmentum of the brainstem
What does the PAG do?
Regulates substantia gelatinosa; decides how much the substantia gelatinosa opens
What lobe is the core of emotions?
Limbic
Where is the Substantia Gelatinosa located?
Dorsal Spinal Cord
What does increased pain do to the RAS?
Activates RAS in the RF found in MB & Pons to activate the cortex resulting in alertness.
Central Modulation of Pain Perception acts on
Dorsal horn of the SC
What can the central modulation of pain do?
can enhance or inhibit pain depending on the emotional framework
Subserved by diffuse projections of pain fibers to the limbic and frontal lobes
Affective motivational aspect of pain
What does the affective motivational aspect of pain do?
It is the main factor of how pain is perceived by the brain
What neurotransmitter brings pain stimuli across the SGR?
Substance P
Pain from skin, bone, organs, ligaments, and muscles
Nociceptive pain
Pain from the dysfunction of the nervous system
Neuropathic pain
Protective role of nociceptive pain
Elicits reflex and behavioral responses that keep tissue damage to a minimum
Pain that originates or comes from cutaneous nociceptors
Somatic pain
Pain that originates or comes from nociceptors found in hollow organs
Visceral pain
Neuropathic pain may be
central or peripheral
pain that
occurs without identifiable nerve or tissue damage.
Central sensitization or dysfunctional pain
Duration of Central sensitization or dysfunctional pain
long-lasting duration
Scope of dysfunctional pain
Extends beyond the receptive field (widespread)
Examples of dysfunctional pain
Fibromyalgia
Irritable bowel syndrome
Types of nociceptive pain
ischemic
inflammatory
traumatic
metabolic
toxic
A type of nociceptive pain that results from lack of blood flow to the cells
Ischemic
A type of nociceptive pain that results from infections
Inflammatory
A type of nociceptive pain that is caused by external forces
Traumatic
An example of this type of pain is uric acid that creates gouts.
Metabolic
Examples of central neuropathic pain
Stroke
Tumor
Demyelinating diseases
How much pain does nociceptive pain inflict?
Proportionate to the stimulus.
How much pain does neurologic pain inflict?
Disproportionate to the stimuli
PNS Lesions
Diabetic neuropathy
Phantom limb pain
Trigeminal neuralgia
LBP
Carpal tunnel syndrome
CNS Lesions
Lesions in the VPL
Stroke
Myelopathic pain due to MS
Type of pain present in neuropathic pain
Burning
Shooting
Stabbing
Vice-like
Electric shock-like
A neuropathic pain that comes and goes
Paroxysmal
A neuropathic pain that does not need any noxious stimuli
Spontaneous
A neuropathic pain that is tolerable
Paresthesia
A neuropathic pain that is no longer tolerable
Dysesthesia
Onset of neuropathic pain
Immediate or delayed
Pain stimulus in neuropathic pain
Allodynia
Hyperalgesia
Hyperpathia
Clinical features associated with neuropathic pain
Insomnia
Anxiety
Depression
Weight loss
Decreased quality of life
Burning, shock-like pain
Spontaneous pain
Abnormal, unpleasant sensations
Dysesthesia
Abnormal, not unpleasant sensation
Paresthesia
Painful response to a non-painful
stimulus
Allodynia
Heightened response to a painful
stimulus
Hyperalgesia
Delayed, explosive pain to a painful
stimulus
Hyperpathia
decreased sensitivity & a raised
threshold to painful stimuli
Hypoalgesia
3 General Mechanisms of Neuropathic Pain
Ectopic focus
Peripheral and General Sensitization
Loss of Local and Central Inhibition
damage in the CNS or PNS that will
fire by itself with pain stimuli
Ectopic focus
Does neuropathic pain need noxious stimuli?
No
Why does neuropathic pain still illicit pain despite not having any stimulus?
Spontaneous firing of axons at once
Regenerating sprouts
Neuromas
What do neuromas express
Na+ channels
What does damage in the PNS do?
Enhances pain; makes receptors very sensitive to stimulus
Where is diabetic neuropathy more common?
Lower extremities than upper extremities
Viral infection of the peripheral nn that presents with sharp burning pain in the involved dermatome
Herpes Zoster
Inadequate relief of herpes zoster may lead to
Post herpetic neuralgia
An injury in the msk system that gets worse with time
Complex Regional Pain syndrome
Complex regional pain syndrome often result in
impairment of motor function
Conditions that lead to CRPS
reflex sympathetic dystrophy
causalgia
shoulder hand syndrome
acute bone atrophy
post-traumatic OP
refers to burning pain
causalgia
local treatments to neuropathic pain
thermotherapy, electrotherapy, anesthesia, capsaicin
what nerve block treatments are there for neuropathic pain?
peripheral nerve, roots, plexus; sympathetic ganglia
Anti-convulsant for neuropathic pain
Caramazepine
Gabapentine
Pregabalin
Valporic Acid
Lamotrigine
Opioids for neuropathic pain
Oxycodone
Tramadol
Topical prep for neuropathic pain
Capsaicin
Lidocaine 5%
Anti-depressants for neuropathic pain
TCAs - lines
SSRIs - tines
SNRI - xines
make you tell the px that the
pain will get better
Placebo
tell the patient that they will
feel more pain
Nocebo
aware that they are given the drug
Open analgesic
not aware that they are given the
drug
Hidden analgesic
