BY DR.SANDEEP ASSESSMENT OF PAIN
BY DR.SANDEEP
ASSESSMENT OF PAIN
PAINDEFINITION:
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
INTRODUCTION
There is no objective measurement of pain.
The pain history is the key to assess it & includes patient description of pain intensity, quality, location, timing, duration and aggravating and relieving factors.
INTRODUCTION
Diagnosis and assessment of Acute pain requires frequent and consistent assessment as a part of daily clinical care to ensure rapid titration of therapy & preemptive intervention.
Chronic pain is often more diagnostically challenging . Structured history and clinical examination will define treatable problems.
Pain and Disability
Nociception
Other physical symptomsPhysical impairment
Neuropathic Psychologic Social isolationmechanisms processes Family distress
Sense of loss or inadequacy
Pain
Disability
ASSESSMENT OF PAIN
Why assess:
Beyond Codes of EthicsBeyond regulatory requirements
Determine ability to participate Ensure safety Diagnose Monitor progress Intervention modification Pain control/modification
Hierarchy of Pain Assessment Techniques
A. Self Report B. Search for Potential Causes of Pain:
A change in behaviour requires careful evaluation of the possibility of additional sources of pain.
C. Observe Patient Behaviours: In the absence of self report, observation of patient behaviouris a valid approach to pain assessment. Not always accurate reflections of intensity and may indicate another source of distress
D. Surrogate Reporting
ASSESSMENT OF PAIN
PAIN HISTORY: General medical history Specific pain history (intensity,
location, pathophysiology, etc,..
PAIN ASSESSMENT TOOLS No objective measurement
Intensity of pain is the most difficult and frustrating
characteristics of pain to pinpoint
Few scales and tests are available.
PAIN ASSESSMENT SCALES
UNIDIMENSIONAL SELF REPORT SCALES
Very simple, Useful
Valid method to assess
VERBAL DESCRIPTOR SCALES
Five word scaling
MILDDISCOMFORTINGDISTRESSINGHORRIBLEEXCRUCIATING
DISADV:
Limited selection of descriptorsPt. tend to select moderate grades than extremes.
VERBAL NUMERIC RATING SCALE
On a numeric scale 0 to 10
0-no pain
10-worst pain imaginable
ADVANTAGES:• Simplicity, reproducibility, easy comprehensibility• Sensitivity to small changes in pain• Children at 5 years, who can count and have concept
about numbers can use this scale
VISUAL ANALOG SCALE(VAS)
Similar to verbal numerical scale
except that the pt. marks on a measured line, one end of which is labeled NO PAIN and other end WORST IMAGINABLE PAIN, where the pain falls
• More valid for research purposes• Less used-more time consuming /
requires motor control
WONG – BAKERS FACIAL PAIN RATING SCALE• Evaluating pain in children is difficult as they cannot describe the pain
Each facial feature is given a number 0 to 5
happy smiling face to a sad, teary face
To extrapolate this scale to the VAS, the value chosen is multiplied by two
oADV: Average children as young as 3 yrs
can use it.
IssuesSome patients have difficulty usingNot good for non verbal patientsSome patients will rate higher than 10:
Credit :http://hyperboleandahalf.blogspot.com/2010/02/boyfriend-doesnt-have-ebola-probably.html
PAIN ASSESSMENT TOOLS
UNIDIMENSIONAL SELF REPORT SCALESVERBAL DESCRIPTOR SCALEVERBAL NUMERIC RATING SCALEVISUAL ANALOG SCALE (VAS)WONG-BAKER FACIAL PAIN RATING
SCALE
MULTIDIMENSIONAL INSTRUMENTS
• Provides more complex information about pt pain
• For assessing chronic pain
• Time consuming (used in research settings)
McGILL PAIN QUESTIONNAIRE (MPQ)
• Most frequently used multidimensional test
• Descriptive words from three major dimensions of pain (sensory, affective, evaluative) are further sub-divided into 20 sub-classes each containing words of various degrees
• 3 scores are obtained one from each dimension and total score is calculated
• Reliable and used in clinical research
BRIEF PAIN IN VENTORY (BPI)
• Patients are asked to rate the severity of their pain at its “worst “,”least” or “average” within the past 24 hrs. and at the time the rating is done.
• It also requires the patient to represent the location of their pain on a schematic diagram of the body
• BPI correlates with activity, sleep and social interaction.
• It is cross cultural and a useful method for clinical study
MASSACHUSETT’S GENERAL HOSPITAL PAIN CENTRE PAIN ASSESMENT FORM (MGHPCPAF):
• It combines many of the foregoing assessment instructions & is given to all pts on initial consultation at their hospital
• Elicits information about pain, therapies tried, post &present medications
DISADV:Time consuming & not applicable
if there are language constraints.
PAIN ASSESSMENT TOOLSUNIDIMENSIONAL SELF REPORT SCALES
VERBAL DESCRIPTOR SCALEVERBAL NUMERIC RATING SCALEVISUAL ANALOG SCALE (VAS)WONG-BAKER FACIAL PAIN RATING SCALE
MULTIDIMENSIONAL INSTRUMENTSMcGILL PAIN QUESTIONARRE (MPQ)BRIEF PAIN INVENTORY (BPI)MASSACHUSETT’S GENERAL HOSPITAL
PAIN CENTER PAIN ASSESSMENT FORM(MGHPCPAF)
PAIN DAIRIES:
• Helps in evaluating the relationship b/w pain and daily activity
• Pain can be described using Numerical Rating Scale, during activities(walking, standing, sitting& routine works)
• Evaluation done on hourly basis• Use of medications & alcohol &
emotional response of pt can also be recorded
• It reflects pt pain more accurately than a retrospective description.
PAIN ASSESSMENT TOOLSUNIDIMENSIONAL SELF REPORT SCALES
VERBAL DESCRIPTOR SCALEVERBAL NUMERIC RATING SCALEVISUAL ANALOG SCALE (VAS)WONG-BAKER FACIAL PAIN RATING SCALE
MULTIDIMENSIONAL INSTRUMENTSMcGILL PAIN QUESTIONARRE (MPQ)BRIEF PAIN INVENTORY (BPI)MASSACHUSETT’S GENERAL HOSPITAL
PAIN CENTER PAIN ASSESSMENT FORM(MGHPCPAF)
PAIN DAIRIES
PAIN LOCATION:• Location and disrtibution of pain helps in
understanding the pathophysiology of pain• Is pain localised/referred• Is pain superficial/peripheral/visceral
Visceral afferent information converge with superficial afferent input at the spinal level, referring the perception of visceral pain to a distant dermatome
PAIN ETIOLOGY:
by asking complete history and if pain is –super
ficial/peripheral/visceral - localised/referred
Cause can be known
PHYSICAL EXAMINATION
GPE• Head to toe examination• Main things are • Appearance –obese, emaciated,
histrionic, flat affect• Posture- splinting, scoliosis, kyphosis• Gait- antalgic, hemiparetic, using
assistive devices• Expression- grimacing, tense,
diaphoretic, anxious• Vital signs- sympathetic over activity
SPECIFIC PAIN EVALUATIONHistory directs the search for physical findings
• Skin: color change, flushing, edema, hairloss, presence or absence of sweating
• Nails: dystrophic changes• Nerve root injury-goose flesh (cutis
anserina) in affected dermatome• Palpation allows mapping of painful areas,
detection of change in intensity of pain and defines pain type & trigger points
• Pt response is noted(verbal/non-verbal)• Also identifies any changes in sensory
modality & pain processing which may manifest as anesthesia /hypesthesia/analgesia
NEUROLOGICAL EXAMINATION:MENTAL FUNCTION:Patient orientaion to time, place, personShort term, long term memoryChoice of words used to descirbe
symptoms and answer questionsEducational background
CRANIAL NERVES:If pt c/o head, neck, shoulder pain
SPINAL NERVE FN:Light touch, sharp pain & propriceptionDTR±, BIBINSKI±
COORDINATION:
Balance, rapid hand movement, finger nose test, knee heel test, rhomberg test, gait
SENSORY SYSTEM
Routine sharp and dull sensationMechanical and thermal allodyniaSummation and after sensationHyperalgesia and hyperpathia
Dynamic allodynia – light rub finger tip/ foam/cotton
Static allodynia –slowly apply perpendicular pressure
Thermal allodynia – warm/cold test tube / tuning fork
Hyperalgesia –single pin prick, multiple pin prinks for summation / after sensation
MUSCULOSKELETAL SYSTEM EXAMINATIONUsually evident on inspecting pt. posture
and muscular symmetryMuscular atrophy – disuseFlaccidity – weakness / paralysis /
abnormal movement due to CNS / proprioceptive damage
Limited range of movement of major joints – pain / disc ds / Arthritis
Palpation of muscles - determines trigger points and evaluates range of motion
ASSESSMENT OF PSYCHOLOGICAL FACTORS:• Psychological aspects of pain• Effects of pain on behavior and emotional
stability
Use of descriptive pain questionnaire such as MPQ may provide some evidence of a pts affective response to pain
aching and tingling-sensory aspect of pain
agonising and dreadful- negative feelings
Pt personality influences his/her response to pain & choice of the coping strategy.few pts use strategies of control- distraction and relaxationanxious pts use high dose of analgesics
Pt with chronic pain-depressed mood, sleep disturbance, decreased activity, preoccupation with somatic symptoms, decreased libido and fatigue
MMPI(Minnesota Multiphasic Personality Inventory ) Grading may expand the assessment
Pt with chronic pain score very high on depression hysteria and hypochondriasis scales.
It reflects functional limitation, secondary to chr pain as well as psychological abnormality
Predisposing factors include:- Major Depression, Somatisation disorder, Conversion syndrome, Hypochondriasis, and psychogenic pain disorders.
Psychogenic pain: Multiple locations of pain at different
timings Pain problems dating since adolescence Pain without obvious somatic cause Multiple elective surgical procedures Substance abuse Social or work failure
PEDIATRIC PAIN ASSESSMENTSCALES DO NOT ALWAYS REPRESENT MULTIDIMENSIONAL ASPECT OF PAIN
BIRTH - 2 YEARS
Pain Perception
Neonates as young as 24-weeks feel pain
Ascending nerve tracts develop earlier than the pain inhibiting nerve tracts meaning that neonates may experience a greater intensity of pain than older children
Neonates exposed to repeated painful stimuli show increasing sensitivity
Neonatal/Infant Pain Scale(NIPS)
BIRTH - 2 YEARS (CONTINUED)
Cognition No “understanding” of pain and unable
to provide a self-report 12 to 18 months, beginning of reasoning
and language (1- or 2-word statements) Major cognitive processing through
senses (eyes, ears, hands) CHEOPS (1-7 years)
Looks at types of pain behavior: cry, facial, verbal, torso, touch and legs.
Neonatal Facial Coding System (NFCS) has been extensively applied to the neonatal pain studies
The responses of facial features, including brow bulge, eye squeeze, nasal-labial furrowing and mouth open are related with pain stimulus
Further extension is the multidimensional scoring systems, which combined facial expression with physiological parameters. These include premature infant pain profile (PIPP) neonatal infant pain scale (NIPS) , and Crying Requirement of oxygen supplementation, Increase of heart rate and blood pressure, facial Express, Sleeplessness (CRIES)
NIPS can only provide 1 or 0 index, which is difficult for quantitative comparison.
To provide a system for clinical studies of neonatal pain responses, Neonatal Facial Image Scoring System (NFISS) is introduced.
This results in the lowest score of 0 to highest score of 15 for graded pain responses.
Nociceptive stimulus can induce physiological and behavior changes in neonate
Heart rate, respiratory rate, oxygen saturation, sweating, cranial pressure, vagal tone, cortisol, and catecholamine have all been monitored as physiological parameters in pain responses
The behavior changes include voice volume (crying, weeping, moaning), facial expressions (brow bulge, eye squeeze, nasal-labial furrowing, mouth open, lip purse, stretch mouth, taut tongue, and chin quiver etc), posture (withdrawing, quivering, stiff, hand holding), alertness, feeding pattern, and interacting modes
2 - 4 YEARS
CNS fully developed Development of
autonomy continues Significant language
development Limited logic and
reasoning Self-centered thought
process Visual analog (Wong-
Baker Faces)
7 - 11 YEARS
Logic and reasoning far more developed
Imagination and creativity
Finalism and concept of death
Number pain scale (scale 1-10)
Adolescents (11+ years)
Cognitively adults Same pain assessment methods as adults
Abstract thinking and understanding hypothetical situations
Emotional needs Include them in the process
Respect their privacy Respect their pain reports
NON-VERBAL CHILDREN FLACC Scale
SCORING
CATEGORIES 0 1 2
FACE No particular expression or smile
Occasional grimace or frown, withdrawn and disinterested
Frequent to constant frown, quivering chin and clenched jaw
LEGS Normal position or relaxed
Uneasy ,restless tensed
Kicking or legs drawn up
ACTIVITY Lying quietly, normal position, moves easily
Squirming, shifting back and forth, tense
Arched, rigid or jerking
CRY No cry (awake or sleep)
Mourns or whimpers Occasional complaints
Crying steadily, screams or sobs, frequent complaints
CONSOLABILITY
Content , relaxed Reassured by occasional touching, hugging or being talked to: distractible
Difficult to console or comfort
Hospitals should use a standard pain scale for the various age groups to allow continuity.
Self report scores (e.g. numerical rating scale) can mislead. A score of 4 may denote severe pain to one adolescent while 8 may be severe to another.
Pain can be worsened by anxiety, depression and spiritual crisis. We must consider this in our assessment.
DIAGNOSTIC TESTS
Radiograph:#,metastasis,stenosis,osteophytes etc.
C.T: B0ny lesions MRI: Soft tissue lesions CNS Infarcts, plaques of demyelination DIAGNOSTIC BLOCKS
Somatic pain decreasesCentral pain persistshelps in diagnosis of complex regional
pain syndrome(CRPS).
DRUG CHALLENGESTo predict drug treatment utility
Helps in assessment of pain etiologyEg:- Brief iv infusion of opioid, lidocaine, phentolamine are used to • Predict opioid sensitivity in non
malignant chr pain• Sensitivity to Na channel block in
neuropathic pain• Assess the potential reversibility of
symptoms of components of pain
NEUROPHISIOLOGIC TESTSTHERMOGRAPHY
Increase in temp. in inflamed tissues
MYELOGRAPHYInjection of radio opaque dye into
SAS for seeing disc herniation, nerve root impingement , arachnoiditis, spinal stenosisDISADV:
Post dural puncture head acheMeningeal irritation
BONE SCANNING:Radio active compounds
accumulate in the areas of bone growth / turn over
SKIN BIOPSIES:Immuno-labeled to show
cutaneous nerve endingspainful neuropathic conditions
are associated with loss of nociceptive innervation in the painful regions of the skin
FUNCTIONAL BRAIN IMAGING (PET,FUNCTIONAL MRI):-
Provocative findings about cortical & subcortical processing of pain information
FMRI shows pain remarkably distributed at the cortical level.
THANK YOU
NEUROPHYSILOGICAL TESTING
It is useful because• Helps detect underlying pathology• Helps define pain mechanics• Helps anatomically localize pain instigators• Helps focus treatment on mechanics• Helps predict if pt. will respond to particular
treatment by clarifying mechanism• Used sequentially, helps monitor ds progressa nd
response to treatment• May have medico legal application• Advances pain research by providing quantitative &
reproducible measurements of pain & its various mechanics.
ELECTRODIAGNOSTIC TESTING(EMG) To diagnose PNS disorders Normal value indicates
defect in CNS or Small Fiber Neuropathy
It has two componentsNERVE CONDUCTION
STUDIES (NCS)NEEDLE ELECTRODE
EXAMINATION (NEE)
Helps in determining severity of a lesion and prognosis
NERVE CONDUCTION STUDIES
Electrical stimulation of nerve – measure response in nerve itself / muscle
Types MotorSensory
Additional type of study – “late response” – appearance of a characteristic wave (F) and a reflex (H)
Parameters to be assessed:Amplitude of the response – no. of intact
neuronsLatency Nerve conduction velocity integrity of
myelin sheath
MOTOR NCS: Stimulate
motor nerve and record Compound Motor Action Potential (CMAP) from belly of the muscle innervated.
Then stimulate the nerve proximally for conduction velocity
SENSORY NCS:
Stimulate sensory nerve and record Sensory Nerve Action Potential (SNAP)
Stimulate median nerve at wrist and record SNAP at digital nerve of second finger.
SNAP is smaller in amplitude than CMAP
NEEDLE ELECTRODE EXAMINATION Insert needle electrode in to muscle
belly and look for electrical activity at rest & on voluntary contraction
Used for the diagnosis of denervation / myopathic disorders
FINDINGS IN MUSCLE INJURYRelaxed muscle:
o look at INSERTIONAL ACTIVITY (response to small movements of electrodes)
o look for SPONTANEOUS MOVEMENTS (fasciculations, +ve sharp waves, fibrillation potentials, complex repetitive discharges, myotonic discharges)
Activated muscle:o Size and shape of motor units & their firing
patterns assessed
Denervated muscle:oMotor units reduced in number but fire
excessively fast (REDUCED REQUIREMENT)
FINDINGS IN MUSCLE INJURYMyotonic Dystrophy:
o Large no. of motor fibers fire at a normal rate despite minimal force production(EARLY RECRUITMENT)
Chronic neuropathy: oMotor units are excessively large
Myopathic disorders:oMotor units are smaller than normal
FINDINGS IN NERVE INJURY
Axonal nerve injury/Neuropathy:o NCS : reduced sensory & motor amplitudeso NCV : slightly slowo In mixed nerve injury sensory affected more than motor
Demyelinating neuropathies:o NCV slowedo Distal latencies & F wave latencies- prolonged
NEE:o Decreased recruitment and rapidly firing motor unitso Axonal nerve:fibrillation potentials & other spont
activity +o Chronic axonal neuropathy: reinnervation produces
motor unit remodeling so that other motor units increase in size
TIMING:more than 3 weeks after
injury(wallerian degeneration must occur)
after acute axonal damageCMAP amplitude begin
to decrease at 3 days, peaks 7 daysSNAP amplitude
begins to decrease at 7 days , peaks 11 days
QUANTITATIVE SENSORY TESTING Tests high threshold
pain and temperature sensing mechanisms.
Provides information about function of entire afferent pain pathway
Non invasive, simple, psychophysical tests
Increased diagnostic sensitivity 67 %to 100%
Common tests include: Thermal(warm, cool, hot, cold) mechanical: (light touch and pin prick) Vibratory and electrical stimuli
A delta- stimulated by cold perception & by HP&CP stimuli
C fibers- warm perception & by HP&CP
A beta- vibration
Painful neuropathies- Thermal hypesthesia; hyperesthesia; hypoalgesia;
hyperalgesia Peripheral sensitization - heat hyperalgesia
and inflammation- CRPS-I- cold/heat hyperalgesia
without hypesthesia/hyperesthesia
Central sensitization: tactile allodynia, mechanical hyperalgesia
Postherpetic neuralgia- thermal hypoesthesia & hyperalgesia(anesthesia dolorosa)
Sympathetically mediated changes in Sudomotor pain- reflex (QSART), sweat output, &
vasomotor fn.
THERMAL STIMULI
Pain and temp sensations are closely related as they are transmitted by small high threshold fibers(A delta and C )
Computer regulates the changes in temperature on a small surface electrode placed flat against skin
Thresholds measured are WS,HS,HP,CP
HP felt at 45C WS/CS felt at 1 / 2 C above or below
baseline
VIBRATION STIMULUS
Large A beta fibers Head of vibration device
must make solid, even, balanced contact
Extra pressure alters nerve function
Vibration range is 0 to 130 mic
Delivers at a rate of 0.1 to 4 mic/sec
MECHANICAL STIMULUS
Use of Von Frey Hairs (filaments) of graduated diameter
If pressed on skin hard enough to cause a bend, exert a reproducible and reliable calibrated force
Wt of filaments- 4.5 mg to 447 gms Expressed in terms of tension (
gm/cm ) or pressure (gm/sq cm)
o USES:• Changes in pain threshold(prim/second
hyperalgesia)• To test summation(seen in neuropathic
pain states-spinal cord injury/ post herpetic neuralgia)
• Nociceptive pain states(fibromyalgia, Tm jn disorders
• At least 8 repetitive pinpricks at same area with 2 to 3 sec gap causes escalation of discomfort- HYPERALGESIA
ELECTRICAL STIMULUS
5 Hz - C fibers 250 Hz – A beta fibers 2000 Hz – A delta fibers
Current can be delivered from 0.1 to 9.99 mA
USES:
• Isolate nerve root pathology• Low CPT(current perception threshold)-
inflmn/neuritis• Elevated CPT-neuropathy/loss of nerve
function
AUTONOMIC TESTING
ANS dysfunction is usually due to small fiber sensory neuropathy
EMG is Normal.
SUDOMOTAR FUNCTION:
Testing sympathetic pathways involved in sweatingSympathetic Skin Response:
simple, less reliable, using EMGintersubject variability & habituation of the response with repetitive stimuli- absence of response-abnormality
Quantitative Sudomotor Axon Reflex Test:
high sensitivity and reliability
A special sweat capsule is attached to skin & Ach is iontophorsed through skin to produce skin response
sweat is then collected in capsule and then quantified
Thermoregulatory sweat test:
Sensitive and Reliable
Powder that changes color when exposed to sweat is applied all over the body allowing areas of anhidrosis to be mapped
CARDIOVAGAL & ADRENERGIC FUNCTION:
HR response to deep breathing.
HR &BP response to Valsalva maneuver & head upright tilt- detected by Symp & Parasymp fn.
HR response to deep breathing determined by Parasympathetic function only.
Conclusions
Make an accurate diagnosis If you’re not sure, consider trial
of pain management Review patient goals Assess, treat, reassess, treat If unsuccessful, review type of
pain and history
THANK YOU