• Acute & chronic pain
differ in their
neurological
processing, impact,
treatment
• Acute – short duration,
subsequent healing
• Chronic long duration
with underlying cause
– can be chronic
malignant with cancer
or chronic benign with
no disease
• Nociceptors are
activated, cause
autonomic
(sympathetic) and
emotional response
and behaviors
• Pain stimuli produces
physiological & psychic
arousal, responses, and
either precise localization
or chronic pain
• Sharp pain – activates
lightly myelinated fibers
• Tissue damage,
inflammation activates
unmyelinated fibers
• Initial pain, with glutamate
as the transmitter, causes
primary hyperalgesia, then
NO is released that causes
secondary hyperalgesia
(hurts more)
• Pain pathway includes
mesencephalon where
impulses are sent to the
hypothalamus, limbic system,
and cortex for endocrine,
autonomic, emotional
components and can
stimulate the analgesia
pathway
• Narcotics cause analgesia by
binding to endorphin
receptors of the analgesia
pathway, that stimulate
fibers to release transmitters
that inhibit pain signals
• Referred pain and
phantom pain are results
of pain perception
• Referred pain – pain
from internal organs that
is perceived from the
skin or muscles, because
of the dermatome of
incoming signal
• Phantom pain after
amputation
• Pain from cancer is
variable in nature &
pathology, from tumor
mass with compression,
distention, occlusion
• Somatic pain –
tissue damaging
• Neuropathic pain –
altered neural
processing
• Peripheral
analgesics inhibit
prostaglandin
production, by
blocking the
cyclooxygenase
pathway, which
raises pain threshold
and reduces pain
perception
• Narcotics act centrally,
bind to receptors in
spinal cord, brain stem,
cerebrum that
endorphins bind to
and can also produce
constipation, nausea,
euphoria
• Use can lead to
tolerance (decreased
effect)
• Nonmedical techniques
can ameliorate pain,
includes
counterstimulation
with accupuncture,
electric stimulation,
ultrasound
• Headaches can be
symptomatic of underlying
pathology, and headache
syndromes can produce
significant disability
• Pain sensitive structures of
the head are the venous
sinuses and veins, dura
mater at the base of the
brain, meningeal arteries,
and subarachnoid space
• Nerves involved are the
trigeminal, vagus, and upper
cervical nerves
• Eye, ear, sinuses also
sensitive
• Headache types:
• Tension – from muscle
tension
• Migraine headaches –
one side of the head accompanied by nausea
and vomiting, arteriolar
constriction, decreased
cerebral blood flow –
classic has prodrome,
common doesn’t,
complicated includes
numbness or TIA like
symptoms
• Cluster – occur in a
cluster of time, similar to
migraine pain
• Severe traumatic injury results
from burns or mechanical
injury, producing wounds
• Abrasion – removal of
epidermis, usually minor
• Contusion – bruise, damage
to small blood vessels with
blood loss into tissue spaces,
surface unbroken
• Hematoma – focal pooling of
blood in tissue
• Laceration – tear of skin or
organ surface
• Bone fractures – incomplete,
greenstick from bending, simple
with only 2 fragments, comminuted
with many fragments, through skin
is compound, depressed in skull,
pathological because of weakness
• Responses help to
maintain blood flow &
metabolic support with
traumatic injury
• Craniocerebral trauma is
serious because the brain
is delicate, secondary
brain injury from local
infarcts, hydrocephalus,
hypoxia 2ndary to initial
injury
• Concussion – period of
lost or altered
consciousness from brain
injury, usually caused by
torsion of cerebrum
around the brain stem,
reversible interruption of
function, severe
concussions result in
coma
• Coup-contrecoup injury
causes edema,
hemorrahge, laceration
• Hematoma effects are
determined by vessels
involved & location
relative to meninges
• Epidural hematoma –
arterial blood outside
of dura that causes
pressure
• Subdural – from
bridging vein, slow
development, also
expands
• Closed head injury –
no breach of
vasculature
• spinal cord
trauma is linked
to vertebral
trauma
• Most vulnerable
are cervical
vertebrae and
upper lumbar
• Spinal shock
usually is 1st
response – loss
of conscious
movement,
sensation,
reflexes from
initial trauma
• Thoracic cage trauma can disrupt
respiratory movements, lacerate
lungs or heart
• Flail chest with rib fractures
• Pneumothorax with opening into
pleural spaces – open-sucking, vs
tension
• Heart & great vessels can have
contusions, dysrhythmia, bleeding
with trauma, tamponade
• Abdominal trauma
can cause contusion,
laceration, rupture of
viscera, penetration
cause hemorrhage
and infection
• Spleen is especially
vulnerable, can cause
bleeding
• Evisceration –
abdominal organs
escape from the
abdomen
• Peritonitis caused by
spilling of secretions
and contents,
infection
• Athletes have trauma
of limbs
• Ligament tears are
sprains
• Avulsion – ligament
pulls bone off
• Subluxation –
dislocation of joint
• Rupture of muscles
from excessive load
• Thermal injuries results from
heat delivery faster than the
skin can dissipate it, classified
on depth of damage
• Burns cause fluid loss, infection
because of the loss of the
barrier
• 1st degree – epidermis
• 2nd degree – epidermis & part
of dermis
• 3rd degree (full thickness) –
through dermis to
subcutaneous tissue
• Smoke inhalation – systemic
hypoxia & acidosis, toxic
components that enter blood,
damage alveolar surfaces –
exudate forms, surfactant is
inactivated