Assessing Pain

By Orest Kornetsky

The Fifth Vital Sign

Pain: an unpleasant sensory and emotional experience associated with actual or potential tissue damage (International Association for the Study of Pain).

Not only a sensory experience resulting from activation of pain receptors, but also the pt’s emotional and cognitive response.

Pain is personal and subjective

Physiology of Pain

Pain is the result of 2 opposing pathways

1. Pain impulses are carried to the brain, generating sensation of pain– Activation of pain receptors by mechanical (pressure), thermal, or chemical

(histamine, serotonin, bradykinin) stimuli.– Prostaglandins or substance P can enhance the sensitivity of pain

receptors to activation.– Periphery Spinal Cord Thalamus Cerebral Cortex

2. Pain impulses are suppressed by the brain, diminishing pain sensation– Done by endogenous opioids, especially endorphins and enkephalins.– Released at both spinal cord and cerebral cortex– The opioids we give activate the same receptors as these endogenous

opioids

2 Types of PainNociceptive

Results from injury to tissues Carried to CNS by 2 types of

fibers, Aδ and C fibers 2 types Somatic

Results from injury to somatic tissues (bones, joints, muscles)

Described as localized and sharp

Visceral Results from injury to visceral

organs (intestine). Described as vaguely localized

and achy Both forms of nociceptive pain

respond well to opioid analgesics (morphine) and may respond to nonopioids (ibuprofen)

Neuropathic Results from injury to peripheral

nerves Described as burning, shooting,

jabbing, tearing, numb, dead, cold.

Responds poorly to opioid analgesics

Responds well to adjuvant analgesics (antidepressants, anticonvulsants, local anesthetics such as lidocaine)

Phantom limb syndrome. Neuropathic pain which occurs when an arm or a leg has been removed because of illness or injury. But the brain still gets pain messages from the nerves that originally carried impulses from the missing limb. These nerves now misfire and cause pain.

May be caused by cancer or by therapeutic interventions

Direct invasion or metastatic invasion of other sites

Neuropathic pain may be caused through infiltration of nerves

Visceral pain may be caused through infiltration, obstruction, and compression of organs

What kind of pain iscaused by cancer?

Types of Pain (by duration) Acute pain

Short term Following injury, surgery, trauma Dissipates after injury heals

Chronic pain Pain longer than 6 months Malignant or nonmalignant Malignant pain due to invasion of surrounding tissues

(nerves, organs, bone) or interventions such as chemotherapy (causing neuropathy)

Nonmalignant pain often has no protective purpose and is due to abnormal processing of pain from peripheral and central sites

Assessing Pain Location – Where is your pain? Do you feel pain in more than

one place? Can you point to the location of pain? Onset and temporal pattern – When did it begin? How often

does it occur? Has the intensity increased, decreased or remained constant?

Quality – What does your pain feel like? Is it sharp or dull? Does it ache? Is it burning or tingling?

Intensity Modulating factors – What makes your pain better? What

makes it worse? Previous treatments – What have you previously tried to relieve

your pain? Was it effective? Function – Does your pain affect your ability to function and

how? Does it interfere with work, eating, sleeping, etc?

Assessing Pain

Numeric – “Can you rate your pain on a scale of 0 to 10 with 0 being no pain and 10 being the worst pain you can imagine.”

Descriptive – for older adults. List words to describe intensity of pain.

Wong-Baker FACES Scale -

Assessing Pain – Nonverbal Cues

Acute Pain Grimacing, moaning, agitation,

diaphoresis Change in vital signs (tachycardia,

increased BP, hypoventilation) Other physiological changes (N&V,

decreased immunity, muscle spasms, depression)

Chronic Bracing, rubbing, diminished activity,

sighing, appetite change

Developmental Considerations

Infants Lack inhibitory neurotransmitters until 38 weeks

gestation more sensitive if preterm It’s now believed to be a myth that infants don’t

feel pain Aging adults

Don’t assume pain is normal

Question 1

During your physical exam, your patient is diaphoretic, pale, and complains of pain directly over the LUP of the abdomen. This would be categorized as:

1. Cutaneous pain

2. Somatic pain

3. Visceral pain

4. Psychogenic pain

Question 2

While caring for an infant, you are aware that:1. Inhibitory neurotransmitters are in sufficient

supply by 15 weeks’ gestation

2. The fetus has less capacity to feel pain

3. Repetitive blood draws have minimal long-term consequences

4. The preterm infant is more sensitive to painful stimuli

Question 3

The most reliable indicator of pain the in the adult is:

1. Degree of physical functioning

2. Nonverbal behaviors

3. MRI findings

4. The client’s self report

Question 4

While examining a broken arm of a 4-year old boy, select the appropriate assessment tool to evaluate his pain status

1. 0-10 numeric rating scale

2. Wong-Baker scale

3. Simple descriptor scale

4. 0-5 numeric rating scale

Question 5

The CRIES is an appropriate pain assessment tool for:

1. Cognitively impaired elderly

2. Children ages 2-8

3. Infants

4. Preterm and term neonates