True or False: Neuropathic pain is a disease.
FALSE. It is a syndrome. It is found in many neurologic conditions, affecting both the central and peripheral nervous system.
The physiologic detection of injury or potentially tissue-damaging thermal, chemical energy impinging upon specialized nerve endings that mediate pain sensation.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
a. Nociception
Advocated to be the 5th
vital sign.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
b. Pain
Unpleasant sensory and emotional experiences
associated with actual or potential tissue damage; the actual sensation and emotion.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
b. Pain
Feelings/emotions elicited because of pain.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
c. Suffering
The reaction to the pain.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
d. Pain behavior
Any type of output that is commonly understood to suggest the existence of a tissue-damaging stimulus.
a. Nociception
b. Pain
c. Suffering
d. Pain behavior
d. Pain behavior
True or False: The quality and quantity of sleep is affected by pain.
True.
ACUTE or CHRONIC pain?
Physiologic in nature.
ACUTE.
- Chronic more often a pathologic phenomenon
ACUTE or CHRONIC pain?
Due to obvious tissue damage
ACUTE.
*Chronic pain is more often due to loss of protective function and degradation of health and function.
ACUTE or CHRONIC pain?
Serves a protective function.
ACUTE.
ACUTE or CHRONIC pain?
Pain resolves upon healing.
ACUTE.
*Chronic pain lasts beyond normal time for healing.
All of the following are examples of nociceptive pain, EXCEPT:
a. Pain due to inflammation
b. Joint pain in osteoarthritis
c. Limb pain after a fracture
d. Nerve entrapment
d. Nerve entrapment
* Nociceptive pain is due to direct stimulation of nociceptors and more LOCALIZED.
REMEMBER that Neuropathic pain is initiated by a primary lesion or dysfunction within the nervous system itself.
Which of the following is classified as MIXED pain?
a. Postherpetic neuralgia
b. Post-operative visceral pain
c. Thalamic Pain
d. Carpat tunnel syndrome
d. Carpal tunnel syndrome.
- Mixed pain means pain with both neuropathic and nociceptive components. Examples include, cancer pain: nociceptive, when mass effects of the tumor include direct stimulation and compression of nerve bundles and neuropathic due to direct nerve lesions and effects of chemotherapeutic agents.
Which of the following is incorrectly paired?
a. Spinothalamic tract - Direct - pain and temperature
b. Spinoreticular - Indirect - autonomous response
c. Spinomesencephalic - Direct - affect
d. Spinoreticular - Indirect - arousal
c. Spinomesencephalic - Direct - affect
The spinomesencephalic tract is indirect.
fast, thinly myelinated “aray” fibers.
A-delta fibers
slow, unmyelinated “hapdi” fibers.
C fibers
ACUTE or CHRONIC pain?
AMPA Receptor
ACUTE.
The AMPA receptor is a directly ionotropic non-NMDA receptor and is responsible for acute pain.
Necessary for NMDA receptor to activate
Glycine moeity.
Periaqueductal Gray Matter is rich in opiate-secreting neurons called:
enkephalins
The fastest neuron.
Alpha motor neuron.
*Alpha motor neuron > A-beta touch fibers > A-delta fiber > C-fibers
Abnormal but not painful.
a. Dysesthesia
b. Paresthesia
c. Allodynia
d. Hyperpathia
b. Paresthesia
- Paresthesias are a type of positive sensory, spontaneous symptom of neuropathic pain.
ex: sensation of crawling ants, tingling
* Dysesthesia - abnormal and painful. Ex. shooting, electric-like, burning.
Painful response to a nonpainful stimulus.
a. Dysesthesia
b. Paresthesia
c. Allodynia
d. Hyperpathia
c. Allodynia
Allodynia is a stimulus evoked symptom of Neuropathic pain (still under postive sensory symptoms)
e.g. pain when wind and bed covers brush on skin
*ALLODYNIA IS PATHOGNOMONIC for Neuropathic pain
Delayed, explosive pain/sustained pain to painful stimulus even if it is removed.
a. Dysesthesia
b. Paresthesia
c. Allodynia
d. Hyperpathia
d. Hyperpathia.
Other types of stimulus-evoked symptoms of neuropathic pain:
allodynia - painful response to a nonpainful stimulus
hyperalgesia - heightened response to a PAINFUL stimulus.
The progressive increase in the response of the system to repeated stimuli.
Activation-dependent plasticity.
What are the mechanisms of pain chronification?
1) ECTOPIC DISCHARGES - Increased pain experience that eventually worsens to experiencing pain even without stimulus, due to a nerve cell injury that increases excitability of the cell.
2) PERIPHERAL SENSITIZATION - . An initial noxious stimulus
results in nerve damage and the release of substance P and prostaglandins. The release of these mediators forms an inflammatory soup, which sensitizes the adjoining afferent fibers. This leads to pain sensation beyond the area initially affected.
3) WIND UP - Due to the repetitive charges transmitted to the dorsal horn neurons by the C-fibers, adjacent dorsal horn neurons are stimulated, thus the pain sensation is greater, giving rise to hyperalgesia.
4) STIMULUS-DEPENDENT CENTRAL SENSITIZATION - appearance of early genes and gene expression and chronification of pain, resulting from activation of both AMPA and NMDA receptors. Forms “pain memory”.
5) DISINHIBITION - In neuropathic pain, the descending inhibitory control is lost, thus the nociceptors are more active, and there is greater transmission to the Dorsal Horn Nucleus,
which results into greater pain sensation.
Identify the sites of action of the following drugs:
TCAs -
Anti-convulsants -
NSAIDS -
Opioids -
1) TCAs - PNs, Spinal cord, CNS
MOA: inhibition of reuptake of serotonin and norepinephrine -> Increased levels of serotonin and
norepinephrine in the CNS -> Greater inhibition on the dorsal horn neuron; also inhibit of Na+ channels, NMDA receptors
2) Anti-convulsants - PNs, Spinal Cord
MOA: inhibition of action potential (PNs) and inhibit reuptake of norepinephrine (Spinal cord)
3) NSAIDS - terminal nociceptors
MOA: inhibit prostaglandins
4) Opioids - PNs, Spinal Cord, CNS
MOA: inhibit action potential, inhibit reuptake of norepinephrine and epinephrine, etc.
The drug of choice for painful DM neuropathy
a. Clonazepam
b. Carbamazepine
c. Gabapentin
d. Lamotrigine
c. Gabapentin
- Decreases Calcium channel activity at presynaptic neuron and block release of pain neurotransmitters.
The drug of choice for trigeminal neuralgia.
a. Clonazepam
b. Carbamazepine
c. Gabapentin
d. Lamotrigine
a. Clonazepam
- Increases GABA activity. (It is an anticonvulsant)
Has the least amount of side effects since it bypasses the liver and have little drug-drug interactions:
a. Clonazepam
b. Carbamazepine
c. Gabapentin
d. Lamotrigine
c. Gabapentin
* Gabapentin and Pregabalin.
* TCAs have the most side effects. So don’t give to elderly patients since it may cause arryhtmia and have uncomfortable side effects.
Depletes substance P from sensory nerves in skin.
a. Capsaicin
b. Lidocaine
c. Tramadol
d. Pregabalin
a. Capsaicin
