CH 6Nociception and Pain Flashcards
Pain is
primarily a symptom rather than a disease
-often the chief complain
Pain scales do what
compare pain over time but not among patients
Acute pain is
- an adaptive mechanism
- protects from potential threats
Chronic pain
- malfunction of the nervous system
- can be considered a disease
Nociception
pathological processes of pain
Transduction
conversion of painful stimulus to action potentials at the sensory receptors
nociceptors
free nerve endings
modulation
modification of nociceptor impulses can occur in the spinal cord, peripheral nociceptor endings, and the brain
Endorphin
Endogenous peptides that produce analgesia
Dermatome
sensory area that corresponds to a spinal nerve
Perception
neural processing of pain sensations in the brain
transmission
Process by which specialized sensory nerve fibers carry impulses to the central nervous system
prostaglandins
formed by cell damage, lower nociceptive fiber threshold (make pain worse)
SIgns and Symptoms of SNS pain response
Increased HR Increased BP Increased RR Dilated pupils Pallor and perspiration nausea and vomiting urine retention
SNS physiological pain response
-blood shifts from superficial vessels to striated muscle, heart, lungs, and brain
-bronchioles dilate to increase oxygenation
-increased gastric secretions
-Decreased gastrointestinal motility
-increased circulating blood glucose
hypermotility of bladder and ureters
How does physiological pain differ from pathological pain?
Physiological pain is the result of tissue injury while pathological pain develops after injury and results from nervous system changes
What is the difference between acute and chronic pain?
Pain is considered chronic when it lasts >6 months. Generally, acute pain resolves when tissue injury heals
How do neuropathic and nociceptive pain differ?
Neuropathic pain results from nerve injury rather than stimulation of pain receptors as in nociceptive pain
Why is pain referred?
Nociceptors from internal organs converge with somatic afferents from the body’s surface
What is the cause of ischemic pain?
tissue hypoxia and injury lead to release of inflammatory and pain mediators
Acute Pain: Headache
- very common
- tension, migraine, sinus headaches
Acute pain: Migraine
- probably due to dysfunction of brainstem and release of inflammatory chemicals
- involves a trigger
- Rule out life threatening conditions like brain tumor, infection, increased intercranial pressure, H&P exam
Acute Pain: Strained muscle, broken bone, appendicitis
- damaged tissue and associated pathology
- often involves inflammation
Chronic Pain Example
Fibromyalgia
- collection of symptoms
- no identifiable physiological cause
- not degenerative or progressive
Peripheral sensitization Theory of chronic pain
- reduction of threshold + amplification in responsiveness of nociceptors
- increased peripheral transduction sensitivity
Central Sensitization Theory of Chronic Pain
- changes in the properties of neurons in the CNS
- increased spontaneous activity
- reduced threshold for activation by peripheral stimuli
- increased responsiveness to stimulation
- enlargement of receptor field
Cancer pain is
- often chronic, called malignant pain
- can suffer from acute pain due to
- -growing tumors: referred or ischemic pain
- -secondary to treatment, radiation or chemo
Expression of Pain
-overt physiologic responses of acute pain may no longer manifest in chronic pain=
Individual expression of pain factors
age
gender
cultural influences
Pain in older adults is often…
often not treated adequately
