Pain Flashcards
How can pain be defined
An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
Sensory receptors
Monitor conditions inside or outside the body
The receptive field
The area monitored by a single receptor cell
The smaller the receptive field…
The more precise the sensory information can be localized
Sensation
The arriving sensory information in the form of action potentials
How is pain sensation information routed
Routed to specific cortex based on location and nature of stimulus
Perception
Conscious awareness and interpretation of sensory input by the integration areas of cerebral cortex
Adaptation
A reduction in sensitivity in the presence of a constant stimulus
Reduces the amount of information arriving at cerebral cortex
General sense include
Temperature Pain Touch Pressure Vibration Proprioception (body position)
Classes of General Sensory Receptors
Nociceptors
Thermoreceptors
Mechanoreceptors
Chemoreceptors
Nociceptors
Respond to pain
Thermoreceptors
respond to temperature
Mechanoreceptors
respond to physical distortion
chemoreceptors
Respond to chemical stimuli
What are nociceptors
Free nerve endings in skin, muscles, joints, arteries, and the viscera that respond and adapt very slowly to chemical, mechanical, and thermal stimuli
Nociceptors are very common in
in superficial skin, joint capsules, covering of bones, and around blood vessels
Nociceptors respond to…
Extremes of temperature, mechanical damage, or dissolved chemicals
What is the size of nociceptors receptive fields
Large that can detect a wide range of stimuli
Neuroanatomy of pain
Transduction
Transmission
Perception
Modulation
Transduction
activation of nociceptors
Transmission
Conduction to dorsal horn and up spinal cord
Perception
Sensory-discriminative system
Motivational-affective system
Cognitive-evalautive system
Modulation
Facilitation or inhibition of transmission before, during, or after perception
Where are neuromodulators located?
Pathways of nervous system
What are neuromodulators triggered by?
tissue injury and inflammation
Which are excitatory neurotransmitters in CNS and PNS
Substance P
Glutamate
Calcitonin
Inhibitory neurotransmitters
GABA
Glycine
Serotonin
Norepinephrine
Pathways of Modulation
Descending inhibitory or facilitatory pathway
Segmental inhibition of pain
Diffuse noxious inhibitory control (DNIC)
Placebo effect
Descending inhibitory or faciliatory pathway
Inhibits or facilitates pain by activating opioid receptors
Segmental inhibition of pain
A beta fibres stimulate inhibitory interneurons and decrease pain transmission
Diffuse noxious inhibitory control
Pain relieved when 2 noxious stimuli occur at the same time from different sites
Placebo effect
Cognitive expectations cause physiological effects
Pain Threshold
Point at which a stimulus is perceived as pain
Perceptual dominance
Pain at one location may cause an increase in the threshold in another location
Pain tolerance
Duration of time or the intensity of pain that a person will endure before initiation of pain responses
Types of pain
Fast pain
Slow pain
Referred pain
Fast pain
Also known as prickling pain
Localized sensations
Transmitted quickly to CNS through myelinated axons
Slow pain
Also known as burning and aching pain
Transmitted by unmyelinated axons
Identified only as general area involved
Referred pain
Perception of pain in an unrelated area of the body
Usually from pain related to visceral organs
Sources of pain
Visceral pain
Deep somatic pain
Cutaneous pain
Referred pain
Classification of pain
Acute
Chronic
Acute pain
Intense pain over a defined period of time
Pain lasts over a few days and may result in increased heart rate, respiratory rate and sweating
Typically occurs over less than 6 weeks
Chronic pain
Longer than 3-6 months
Can interfere with daily activities
Acute pain protective mechanism
Alerts an individual to a condition or experience that is immediately harmful to the body
Acute somatic pain
Arises from skin, joints, and muscles
Acute somatic Pain A delta fibres
Pain is sharp and well localized
Acute somatic pain C fibres
Dull aching and poorly localized pain
Acute Visceral Pain
Pain in the internal organs and lining of the body cavities
Acute visceral pain transmitted by C fibres
Poorly localized with an aching, gnawing, throbbing or intermittent cramping quality
Neuropathic pain
Chronic
Amplification of pain without stimulation
Neuropathic pain is often described as
Burning, shooting, shock like or tingling
Peripheral neuropathic pain
Caused by peripheral nerve lesions
Central neuropathic pain
Caused by lesion or dysfunction in brain or spinal cord
PQRSTU
Provocative or palliative Quality of pain Region of body Severity Timing and onset of pain Understanding of pain
Who is an expert on their pain
the patient
Barriers to effective pain management
Lack of information Limited training Fear of addictive nature of opiates Lack of information with combining therapies ineffective assessment
Nonpharmacological Pain interventions
Massage Positioning and body alignment Splinting Thermal interventions Mind-body therapies Acupuncture Biofeedback therapy Relaxation therapy Art or music therapy Imagery Chiropractic manipulation Hypnosis Therapeutic touch Transcutaneous electrical stimulation Energy therapies Physical and Aquatic therapy
Two categories every of analgesics
Non opioids
Opioids
When should non opioids be used
Minor (0-4) to moderate pain (4-6)
When should opioids be used
Severe pain (7-10)
Adjuvant analgesics
Enhance the analgesic action of non opioids and opioids
Assist the primary drugs in relieving pain
Allow for smaller dosages of opioids to be described
Non opioids
Acetaminophen
NSAIDS
Tramadol
Clonidine
Opiod Analgesics
Morphine
Fentanyl
Hydromorphone
Oxycodone
Adjuvant analgesics
Local anesthetic (Bupivacine, Ropivacaine, lidocaine)
Anticonvulsants (Gabapentin, pregabalin)
Antidepressants (Desipramine, nortiptyline, duloxetine)
Endogenous Opioids
Morphine-like neuropeptides
Enkephalins
Morphine-like neuropeptides
Bind with opioid receptors to inhibit pain impulses in periphery, spinal cord and brain
Enkephalins
Have pharmacological actions similar to morphine
Bind as direct agonists to opioid receptors
Most common natural opioid
Endorphins
Dynorphins
Endomorphins
Acetaminophen overdose leads to..
hepatotoxicity due to the formation of toxic metabolites
What is Acetylcysteine used for
Acetaminophen overdoses
Used to reduce the extent of liver damage
detoxifies the toxic metabolite and allows for other routes of metabolism
Adverse effects of Acetlycysteine
Flushing Urticaria Rash Hypotension Bronchospasm
Endocannabinoids are classified as?
Classified as escanoids
What are endocannabinoids synthesized from?
Phospholipids
Endocannabinoids
Cannabis produces a resin contains cannabinoids
Analgesic in humans
Drawbacks of endocannbinoids
Psychoactive and addictive properties
What is the prototype drug for severe pain
Morphine
Opioids
Narcotic analgesic
Can be natural or synthetic
In what type of pain should adjuvant medications be used with opioids
Neuropathic pain
Morphine Sulphate
Controlled substance derived from the opium poppy
CNS depressant
Are epidurals available for morphine sulphate?
yes
Morphine Sulphate Route
PO
IV
SC
IM
Morphine sulphate Onset of action
Rapid
Morphine sulphate Peak
30-60 min
Morphine sulphate half life
1.7-4.5 hours
Morphine sulphate duration of action
6-7 hours
How do opioids work?
Bind to the pain receptors in the brain and cause an analgesic response
Work by exerting their action by interacting with at least 6 types of receptors
MU Receptor responses
Analgesia Decreased GI motility Euphoria Physical dependence Respiratory depression Sedation
Kappa Receptor Responses
Analgesia
Decreased GI motility
Miosis
Sedation
General effects of opioids
Suppress cough reflex Slow GI motility Sedation Euphoria Intense relaxation Respiratory depression Nausea and vomiting Potential for physical and psychological dependence
Use opioids with caution in patients with
hepatic disease
Side effects of opioids
Respiratory depression Constipation Decreased LOC Orthostatic hypotension Nausea and vomiting Urinary output
Opiod overdose
Overly aggressive pain therapy or substance abuse
Most commonly abused opioids
Morphine
Meperidine
Heroin
Manifestations of Opioid overdose
Euphoria Arousable somnolence Nausea Pinpoint pupils Slow and shallow respirations Coma Seizures
Opiod overdose treatment Action
Blocks MU and Kappa receptors
Given if the patient is experiencing severe respiratory distress
Opioid overdose treatment Pharmacokinetics
Well absorbed following SC or IM administration
Widely distributed and crosses BBB and placenta
Opioid overdose treatment half life
60-90 min in adults
Up to 3 hours in neonates
Opioid overdose treatment adverse effects
Minimal toxicity
Rapid reversal for analgesic
Opioid overdose treatment Drug interactions
Reversal or analgesic effects of opioid agonist and antagonist
Opioid overdose treatment prototype
Naloxone (Narcan)
Nursing considerations for naloxone
Know when to administer it
Monitor CV status
Monitor withdrawal post administration
Monitor VS during and after administration
What is the treatment for opioid dependence?
Methadone
Combination Medication
Common practice to combine opioids and non opioids into a single tablet
Work to relieve pain
How do combination medication work?
Keep the doses of narcotic small to reduce dependence and opioid related side effects
Percocet
Oxycodone (HCL)- 5mg
Acetaminophen- 325mg
Atasol 30
Acetaminophen- 325mg
Caffeine- 30mg
Codeine- 30mg
Tylenol with codeine No. 3
Acetaminophen- 325mg
Caffeine- 15mg
Codeine- 15mg
Migraine
Familial, episodic disorder whose marker is headache and is defined as repeated, episodic headache lasting 4 to 72 hours
Migraines are caused by…
Caused by combination of multiple genetic and environmental factors
Diagnosis of Migraine
Unilateral, throbbing, worsened by movement, moderate or severe, and any one of these symptoms: nausea, vomiting, photophobia, or phonophobia
Migraine Triggers
Altered sleep patterns Skipping meals Overexertion Weather change Stress or relaxation from stress Hormonal changes Bright lights Strong smells Chemicals
Cluster headaches
Occur in clusters (minutes to hours) for a period of days, followed by a long period of spontaneous remission
Tension headaches
Most common
Mild to moderate bilateral headache with a sensation of a tight band or pressure around the head with gradual onset of pain
May last hours or days
Headache Treatments
begin with acetaminophen or NSAIDS
then triptans or ergot alkaloids
Triptans
Selective for serotonin řeceptors
Constrict certain inter cranial vessels
Aborts migraine with or without aura
Ergot Alkaloids
Interact with adrenergic, dopamine, and serotonin blockers
Aborts migraines
3 origins of labor pain
Visceral
Somatic
referred
First stage of labor pain
Uterine contractions
Decrease in blood flow causing local oxygen defecit
Pain is felt from uterine contractions
Second stage of labor pain
Sharp burning pain Somatic pain
Distention & tration on the peritoneum and uterocervical supports
Pressure against the bladder & rectum
Stretching & dissention of perineal tissues & the
pelfic floor
Lacerations of soft tissue (cervix, vagina, perineum)
Stage three of labor pain
Uterine in nature
Similar to the first stage of labor
Drug exposure during pregnancy
Opioid use can have a negative effect on mothers and their babies
Infants can be born with breathing and feeding problems
Preterm birth
Low birthweight
Maternal mortality
Neonatal abstinence Syndrome
