Test1 Flashcards
What are the two components of pain according to lecture?
Sensory - can discriminate pain signals;
Motivational - motivate a response to painful stimuli
According to lecture in general what is the ascending pain pathway?
Spinothalamic and trigeminothalamic tracts → cerebral cortex → perception of pain
What are four of the bodies responses to pain?
Attention and arousal;
Somatic and autonomic reflexes;
Endocrine responses;
Emotional changes
What is nociception?
The experience of pain with a series of complex neurophysiologic processes
The International Association for the Study of Pain defines pain as…?
complex physical emotional and psychological condition
What are the targets of pain reducing medications?
transduction;
transmission;
interpretation;
PNS and CNS pain modulation
What percentage of adult population has some form of chronic pain? Of these what is the most common chronic complaint?
40%;
Low back pain (8% to 37%)
In the U.S. pain cost approximately how much annually?
$40 billion
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What is transduction?
Nerve endings sense painful stimuli translate into electrical impulses
When pain is transmitted to CNS where does the signal connect in the spinal cord?
Signals travel to the dorsal horn
Which interventions block the transmission of pain?
Local anesthetics;
Nerve blocks
What is modulation?
Altering pain transmission (either ↑ or ↓) at the dorsal horn
Where is pain perceived?
Thalamus routes pain signals to primary somatosensory cortex for discrimination
Which medications alter the perception of pain?
Opioids;
α2-agonists;
General anesthetics
Which medications modulate pain signals?
local anesthetics;
opioids;
ketamine;
α2-agonists
Which medicatins prevent transmission of pain signals?
local anesthetics
Which medications inhibit transduction?
local anesthetics;
NSAIDS
Acute pain is transmitted on which nerve fibers? Chronic pain?
Aδ - myelinated;
C fibers (unmyelinated)
Where are nociceptors located in the body?
skin;
muscles;
joints;
viscera;
vasculature
What is the ascending pain path for a stimulus to be transmitted to the brain?
Stimulus;
nociceptor - must exceed threshold;
Dorsal Horn;
RVM- rostral ventral medulla;
PAG- (periaquaductal grey)and PB(parabrachial nucleus);
PAGto ThalamusandPBto Amygdala;
Thalamusto Somatosensery areas I and II;
Amygdalato Cingulate cortex and Insular cortex
What stimulus types are transmitted on C-fibers (slow pain)?
heat - burning pain;
pressure - sustained pressure
What stimulus types are transmitted on Type 1 A-fibers (fast pain)?
heat;
mechanical;
chemical
What stimulus types are transmitted on Type 2 A-fibers (fast pain)?
heat
Describe what a Type 1 and Type 2 A-fiber is.
Type 1 - Aβ and Aδ;
Type 2 - Aδ
What is the impulse velocity of A-fibers?
2 m/s
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What are the peptide chemical mediators for pain?
Substance P;
Calcitonin;
Bradykinin;
CGRP
Of all the the chemical pain mediators which type is released first?
Peptides are released first (bradykinin released very first of these)
What are the main classes of chemical mediators for pain (Class Only)?
Peptides;
Eicosanoids;
Lipids - PGs thromboxanes LTs endocannabinoids;
Neutrophins;
Cytokines;
Chemokines;
Extracellular proteases and protons
Which pain receptors and ion channels are involved in the DRG and peripheral terminals?
Applies to IV pain meds only!!;
Purinergic;
Metabotropic;
Glutamatergic;
Tachykinin;
TRPV I;
Neurotrophic;
Ion channels (Nav 1.8)
What is an important difference between acute and chronic pain?
chronic pain often involves sensitization
What is hyperalgesia?
Increased pain sensations to normally painful stimuli.
What is allodynia?
perception of pain sensations in response to normally non-painful stimuli.
Which pathology was used in class as an example that combines both hyperalgesia and allodynia?
Arthritis can have both sensation depending on type
What is the definition of primary hyperalgesia?
Hyperalgesia the original site of injury from heat and mechanical injury.
What are four S/Sx we would see in someone with primary hyperalgesia?
↓ pain threshold;
↑ response to suprathreshold stimuli;
Spontaneous pain;
Expansion of receptive field
What is the definition of secondary hyperalgesia?
Uninjured skin surrounding the injury experiences sensitization of central neuronal circuits
Which structure in the spine is the relay center for nociceptor activity?
Dorsal Horn
The ascending pathways in the spinal dorsal horn connect to which areas in the brain?
Brainstem and Forebrain (Somatosensry 1 and 2) → pain perception location intensity
When does peripheral pain become central pain?
Once pain signal is received in the dorsal horn it becomes central pain
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Which type of nerve fibers connect to Lamina 1 and 2 in the dorsal horn?
Lamina 1 - Aδ and C fibers;
Lamina 2 - C fibers
What is another name for Lamina 2?
substantia gelatinosa
Opioids will work specifically at which two Laminae?
Lamina I and Lamina II
Which fibers connect to Laminae IV VII and the ventral horn?
myelinated fibers (innervate muscles and viscera)
Which lamina is the NK-1 receptor located? Which compound is associated with NK-1 receptor?
Lamina III & IV;
Substance P
What is the Gate Theory of Pain?
Neurologic “gate” in the dorsal horn;
Gate open: pain is projected to supraspinal brain regions.;
Gate closed: pain is not felt with simultaneous inhibitory impulses.
Explain how Aβ Aδ and C fibers operate in the Gate Control Theory of pain
Aδ and C Fibers - open the gate transmit pain (small nociceptive fibers);
Aβ - close the gate inhibit transmission of pain (large fiber mechanoceptors)
Which brain structures are responsible for the motivational-affective component of pain?
Limbic cortex;
Thalamus;
Makes us want to stop the pain - have to act
Which structures in the brain depress or integrate pain info in the spinal dorsal horn?
PAG-RVM SYSTEM
What substances act as neuromodulators?
Substance P;
Glutamate;
CGRP;
NMDA;
AMPA;
BDNF;
Cytokines
When tissue is damaged which neuromodulators are released?
Substance P;
Glutamate
If cells mast cells or platelets are damaged what neuromodulators are released?
Bradykinin;
Histamine;
prostaglandins;
Serotonin;
Hydrogen ion;
Lactic acid
Which neuromodulators in the spinal cord are Excitatory?
Glutamate;
Calcitonin;
Neuropeptide Y;
Aspartate;
Substance P
Which neuromodulators in the spinal cord are Inhbitory?
GABA;
glycine;
enkephalins;
norepinephrine;
dopamine
What are the four Ascending Pathways for nociceptive information we discussed in class?
Spinothalamic;
Spinomedullary;
Spinobulbar (hindbrain);
Spinohypothalamic
What type of nociceptive information is transmitted on the Ascending Spinothalamic path?
Pain;
Temp;
Itch
Which Laminae are associated with the Ascending Spinothalamic path?
LaminaeI VII & VIII (all afferent fibers)
What type of information is transmitted on the Ascending Spinobulbar path?
Behavior toward pain
Which Laminae are associated with the Ascending Spinobulbar path?
Laminae I V & VIl
What type of information is transmitted on the Ascending Spinohypothalamic path?
Autonomic;
neuroendocrine;
emotional aspects of pain
Which Laminae are associated with the Ascending Spinohypothalamic path?
Laminae I V VII X
Which areas of the brain are involved in the Supra-Spinal modulation of pain?
Forebrain S1 and S2;
ACC - anterior cingulate cortex;
IC - insular cortex;
Prefrontal cortex;
Thalamus;
Cerebellum
What roles do the the Anterior Cingulate Cortex and Insular Cortex play in pain modulation?
process the emotional and motivational aspects of pain from signals transmitted from Amygdala
Which areas of the brain are involved in the Supra-Spinal modulation ofDescending Inhibitorytracts?
PAG → RVM → Dorsolateral funiculus → synapse in dorsal horn
Which neurotransmitters are involved with the Descending Inhibitory Tracts?
Endorphins;
Enkephalins;
Serotonin
How do the Descending Inhibitory tracts actually inhibit pain (mechanism)?
Hyperpolarize Aδ and C fibers by ↓ release of substance P opening K+ channels closing Ca++ channels
There are two types of Descening Pain Modulation pathways what are they?
Descending Inhibition Pathway (DI);
Descending Facilitation Pathway (DE)
What are some other factors that are involved in the facilitation or inhibition of pain?
Other somatic stimuli;
Psychological factors (arousal attention and expectation)
Which opioid receptors are found in the PAG-RVM system? What do they do?
μ κ δ;
Play a role in causing hyperalgesia and Allodynia
Where does the pain impulse originate if it is pertaining to the descending inhibitory tract?
PAG-RVM
What are the timelines for acute and chronic pain?
Acute pain (days to weeks after injury);
Chronic pain (> 3 to 6 months: persists beyond tissue healing)
How do emotions affect acute/chronic pain?
Unpleasant emotional experiences use the same pathways - can affect the quality of the pain;
anxiety depression cognitive deficits emotional distress all can make the pain “feel” worse
What is neuropathic pain?
Persists after tissue has healed → This is hyperalgesia and allodynia
Who is at increased risk for Neuropathic pain?
Cancer patients d/t chemo and radiation therapy
How can we treat neuropathic pain?
Opioids;
Gabapentin;
Amitryptiline;
Cannabis
What is Visceral pain?
Diffuse and poorly localized;
Referred to somatic sites like muscle and skin
What are some causes of Visceral pain?
ischemia;
stretching of ligamentous attachments;
spasms;
distention
What are four specific types of pain?
Neuropathic;
Visceral;
Complex Regional Pain Syndrome;
Pain in Neonate and Infant
What is Complex Regional Pain Syndrome?
Multiple painful conditions following injury that impairs sensory motor and autonomic systems
What kind of S/Sx might we see related to Complex Regional Pain Syndrome?
Spontaneous pain;
Allodynia/Hyperalgesia;
Edema;
Autonomic abnormalities;
Active/passive movement disorders;
Trophic changes of sking and SQ tissues
When is it believed that babies begin to feel pain?
23 weeks
What is unique about the pain that babies feel?
They have a lower pain threshold and exaggerated pain response
Describe the CV response to pain?
HTN;
Tachy;
Myocardial irritability d/t ↑ MRO2;
↑ SVR;
↓ CO and Myocardial ischemia (if LV is bad)
What is the Pulmonary response to pain?
↑ total body O2consumption and CO2production;
↑ Vmand work of breathing;
Splinting;
↓ chest wall movement (leads to shunting and atelectasis);
Impaired coughing
What is the GI/GU response to pain?
↑ sphincter tone ↓ motility - leads to N/V/ileus/urinary retention;
↑ secretion of acid - ulcers/aspiration;
Abdominal distention;
N/V
What is the Endocrine response to pain?
↑ catabolic hormones;
↓ anabolic hormones
What are some catabolic hormones we discussed in class?
Catecholamines;
Cortisol;
Glucagon
What are some anabolic hormones we discussed in class?
Insulin;
Testosterone
What effects do we see from the endocrine response to pain
neg nitrogen balance;
Carb intolerance;
↑ renin aldosterone AT
What is the Hematologic response to pain?
All effects releated to stress…;
Platelet adhesiveness;
Reduced fibrinolysis;
Hypercoagulability
What are some emotional responses that pain can cause?
anxiety;
Sleep disturbance;
Depression
What are some immune responses that pain can cause?
Leukocytosis;
↓ reticuloendothelial system - leads to increased infection
