Wk 5: Pain concepts and assessment Flashcards
Define pain
Sensory and emotional experience associated with actual or
potential tissue damage, or described in terms of such damage’
Key points of pain
- a different pheromone for each person
- pt is the authority of their own pain
What are some types of pain?
Times
- Acute (at time of healing)
- chronic/persistent (3-6 months)
Pathways of pain
- Nociceptic (common pain, something wrong with specific tissue)
* Somatic (tissues)
* Vicera (organ tissue)
* chances with movement
e.g. bee stings, muscle injury
- Neuropathic (damaging to the nervous system)
* nerve
* something wrong with NS.
e.g. nerves, pinching, disease
*more likely to be chronic
What are the elements of the nociceptive pain response?
- Transduction
- Transmission
- Perception
- Modulation
What are the three pathways of the NS?
- afferent pathway (asending to the brain)
- Central nervous system (where pain is percieved)
- efferent pathway (motor pathways that come down from CNS)
What are key features of the afferent pathway?
- hold nociceptors (pain receptors)
- afferent nerve fibres
- spinal cord network
- terminated in the dorsal horn of the spinal cord
What are key features of the CNS pathway?
The portions involved in the interpretation of the pain
signals:
* the limbic system
* reticular formation
* thalamus
* hypothalamus
* cortex
What are key features of the efferent pathway?
Composed of the fibres connecting:
* reticular formation (projections into that thalamus)
* midbrain (cantain nerves and nucli)
* substantia gelatinosa in dorsal horn (recieves different types of sensory information)
What are nociceptors? and what are the two types?
Sensory receptors (nerve endings) activated by noxious stimuli, transmit impulses via C fibre and A‐delta fibres
Distributed in:
somatic structures
- skin, muscles, connective tissue, bones, joints);
visceral structures
- visceral organs such as liver, gastro‐ intestinal tract)
What is the speed of C and A-delta fibres?
C fibres: slow
A-delta: fast
Describe transduction
= initial response to injury
- release of chemical mediators
- conversion of energy types
- generation of action potential
Describe chemical mediators of pain
- Prostaglandins (lipid compunds, mediators of alleri/inflamatory reaction so pain and swelling)
- Substance P (vaso dilator, NT, regulates excitability of dorsal horn)
- Histamine (Mast cells) (increase blood flwo, fluid and protien rush to the tissue space= red and swelling)
- Bradykinins (vasodilators and tissue swellers)
- Serotonin (NT released by platlets)
- Potassium (important for opening and closing of potasium channels and creation of action patential)
- Others
Describe the three phases of transmission
Three phases:
1) Injury site to spinal cord
- A‐delta and C fibres
2) Spinal cord to brain stem and thalamus
3) Thalamus to cortex
Describe the asending pathway
ascending = sensory
From nociceptors to brain
- Complex transmission from periphery to dorsal
root of spinal cord
- Terminate in dorsal horn
- Signals communicate with local interneurons
- Neurons with long axons ascend to brain
Describe the desending pathway
descending= motor
From brain to spinal dorsal horn
Can be modulated
- release of chemical substances
- Gate theory
- Actions
Selective response to stimuli
Describe perception
Conscious experience of pain (ouch!) (comes through afferent pathway)
* Reticular activating system (RAS)
* Somatosensory system
* Limbic system
* Cortical structures
Describe modulation and its part of the pathway
Signals from brain travelling downwards
Release of chemical substances
- Endogenous opioids
* Encephalins
* Endorphins
- Serotonin
- Noradrenaline (norepinephrine)
= Amplification of dampening/modulation of the pain system
What are some impacts on modulation?
- Occurs at all levels of the nervous system
- Signals enhanced or inhibited
- Influences pain perception
- Helps explain variability in pain experience
- The “Gate Theory”
Describe delta fibres
- Thinly myelinated
- Large diameter
- Fast-conducting fibres
- Transmit well-localised, sharp pain
- Sensitive to mechanical and thermal stimuli
Transmit signals rapidly: associated with acute pain.
Describe C fibres
- Unmyelinated, small diameter
- Slow-conducting
- Transmit poorly localised, dull and aching pain
- Sensitive to mechanical, thermal, chemical stimuli
- Activation associated with diffuse, dull, persistent pain
- more relted to persistant pain but can be both
Describe delta A fibres
- Highly myelinated
- Large diameter
- Rapid-conducting
- Low activation threshold
- Respond to light touch, transmit
**non-noxious stimuli - Gate theory: tactile non‐noxious stimuli inhibits pain signal transmission
What are the types of somatic pain? and what body parts do they impact?
Superficial somatic
– Skin
– Mucous membranes
– Subcutaneous tissues
Deep somatic
– Muscles
– Bones
– Fascia
– Tendons
– Joints
– Ligaments
– Blood vessels
What impacts pain perception?
- previous experince
What is modulation?
- the inhibition or enchantment of signals
- Occurs at all levels of the nervous system
- Influences pain perception
- Helps explain variability in pain experience
Explain the gate control theory?
- Gate controlled by dynamic function of certain
cells in dorsal horn that stops some impulse getting to the brain. - Substantia gelantinosa within dorsal horn is
anatomical location of gate
Pain experience dependent on:
- amount of information that gets “through”
the gate to the brain
- Competition between large and small fibres
- Competition between pain fibres and non pain fibres
- amount of downward signaling from brain
- Endogenous chemical release
Descending & ascending fibres meet at the gate
- Gate open/closed depending on information received from various sources
- T cells within dorsal horn facilitates the opening &
closing
- Activity such as touch can close the gate
e.g. rubbing the injured site
What are some examples of things that help close the pain ‘gate’
- rubbing
- heat
- tens machine in labour
What is the purpose of pain? and what impacts it?
- Necessary, protective mechanism
- Subjective experience, not necessarily consequential just from an external stimulus
Complex interplay of multiple factors
– Biological
– Psychological/affective
– Sociological
Explain how pain can be contextual?
You may not feel pain at the time as your focous is else where. e.g. soldiger in battle
different to a women in labour expecting a baby
What are the classifications of pain?
Actue or persistant
Neuropathic
Somatoform (psychogenic)
- no identifiable casue but person feels pain e.g psychogenic
Nociceptive
- viceral
- somatic
Others inlcude
- referred pain
- phantom pain
- cancer pain
- intractable pain
- Breakthrough pain
Describe acute pain
- sudden onset
- mild or significant
- duration is dependant on the healing
- sympathetic signs e.g. hypertension, tachy
- is protective pain that indicates something
- can be deep or supericial
- can be apart of a /acute pain cycle’ that recurrent acute episodes e.g. migrane or angina
*life may be distrupted with the pain and then anticipation of pain
Describe persistant pain
aka chronic
- extends beyond normal healing time
- >3-6 months
- gradual or sudden
- mild or sever
- up to 30% of population have this
- usually results in chronic or pathological process
- gradual or ill defines onset
- progressives in severity
- no sympathatic response
- often unresponsive to medical treatment
- no protective pain= doent sever a purpose
- this along with not knowing when it will stop can lead to negative psychological symptoms e.g. depression
Describe nociceptove pain
- Response to nociceptors/nerve pathway
- Normal processing
Describe neurogenic/neuropathic pain
- Nerve damage (peripheral or central)
- Abnormal processing along nerve pathway
Describe somatopain disorder
- no physical cause found to casue pain
- no evidence or organic disease
- moved away from psychogenic disease
- associated with mental health conditions of anxiety or despession
- real and distressing
Name the following of somatic pain
Psychological structures;
Cutaneous: skin and sub‐cutaneous tissues
Deep somatic: blood, muscle, blood vessels,
connective tissue
Mechanism:
- Activation of nociceptors
Sources of pain:
- Incisional pain, insertion sites of tubes and
drains, wound complications, orthopaedic
procedures, skeletal muscle spasms
Sources of chronic pain syndromes:
- Bony metastases
- osteo/rheumatoid arthritis
- Low‐back pain
- peripheral vascular disease
Describe nociceptive viceral pain
- Dull, poorly localised deep pain
- Due to ischaemia, inflammation, obstruction
- Vague associated symptoms, may be
N & V - Referred pain
- Reflex motor
& sympathetic efferent activity - Cutaneous hyperalgesia= increase in sensitivity to pain in the tissue surrounding organ
- May be described as sickening, deep, squeezing, dull
Name the following of somatic pain
Psychological structures;
Organs and linings of body cavities
Mechanism:
- Activation of nociceptors
Characteristics
- Poorly localized, diffuse, deep, cramping or splitting
Sources of pain
- Chest tubes, abdominal tube drains,
bladder and intestinal distension
Sources of chronic pain syndromes:
- Pancreatitis
- liver metastases
- colitis
Describe neuropathic pain
Results from damage to: pathologic changes of, the
peripheral or central nervous system
- May be mediated by NMDA receptor (excitatory NT that is release with noxious peripheral stimuli)
- Pain described as burning, tingling, shooting, electric-like, lightning‐like
- May exhibit opioid resistance or require higher doses for effect
- contract to nociceptic pain
What are some causes of neuropathic pain?
CNS
- Stroke
- MS
- Spinal cord trauma
PNS alteration
- Polyneuropathy e.g. from diabetes
- Entrapment neuropathy (nerve is traped)
- Post herpetic (herpes/shingles) neuralgia
Name the following of somatic pain
Physiologic structures
- Nerve fibres, spinal cord, and central
nervous system
Mechanism
- Non‐nociceptive injury to nervous system
structures
Characteristics
- Poorly localized: shooting, burning, fiery,
shock‐like, sharp, painful numbness
Sources of acute and
chronic pain syndromes
- Nerve tissue injury due to diabetes, HIV,
chemotherapy, neuropathies, post‐herpetic
neuralgia
Describe somatoform pain and what are some symtpoms?
- Previously termed psychogenic pain
- Pain caused, increased, or prolonged by mental,
emotional, or behavioural factors
Diagnosis of exclusion
- Label or diagnosis? Sufferers are often stigmatised
- Headache, back pain and abdominal pain are sometimes diagnosed as SPD
Describe cancer pain?
Due to
- cancer progression
- treatment related e.g. incision
- toxicities or treatments
- physical limitations
- Usually persistent
- Long‐term
- Often treated as acute pain
- Progressive nature
- Those with cancer may experience both persistent and acute pain
- common to come as break though pain
Define breakthrough pain
- Common in cancer patients
- Sudden onset
- Short duration
- Unresponsive to normal pain management
Define intractable pain
= Pain that is excruating and contacnt
- not relieved by ordinary
medical, surgical or nursing measures.
- Pain usually persistent
- causes negative mental health
- can prevent sleep
- can cause over-excitation of CVD so can be seen sometimes on medical tests
Causes
- poly mialgia
- spinal disease post surgery
- migranes
Describe phantom pain
- pain the is felt in a body part that is missing.
- feels as though pain is in part that is is missing
= neuropathic pain
Describe referred pain
Felt at a site other than
the injured/ diseased
organ/body part
- e.g. angina paint hat may be felt in shoulder or jaw
What are some factors that influence pain perception, expression and reaction?
- genetic
- developmental
- familial
- psychological
- social
- cultural
- not related to the extent of tissue damage necessarily as these come into play
What are some psychological and phsyical aspect of pain?
- Anxiety
- Sense of helpless ness
- Poor insight
- Lack of communication skills
- Depressive mood
- Cognitive deficits
- dementia cant explain pain
- Elderly
What are some environmental impacts of pain?
- Unhealthy environment
- No community access
- Poor finances
- Limited education/health literacy
- Stressful living context
- Lack of secure housing
What are some social and interpersonal impacts of pain?
- Lack of family support
- Poor social networks
- Unemployed
- Avoidance of activities
- Being single
- Frequent hospitalisation
What psychological aspects can be affected by pain?
Attention: person pays to it
Expectations: previous experience
Interpretation: attitudes and beliefs
Context: what is the meaning of the pain
Emotions and mood: anxiety, depression, anger, sad
Coping strategies: perception of control
What are some psychological aspected of persistent pain?
- Loss of employment/income
- Depression, fear, anxiety, grief, guilt, anger
- Isolation
- Sleep disorders
- Marital and family dysfunction
- Lowered self esteem and confidence
- Catastrophising
Define transduction and explain how it occurs
the conversion of mechanical, thermal or chemical stiumli to neuronal action potential.
= cell damage releases sentising cibstances such as prostaglandins bradyinins, subsance P, histamine, leukotrines, serotonin and ATP which results in;
1: the generation of an action potenital along the neuronal membrane
2: the abnormal processing of stimuli by the nervous system (neural pain) plus chnage along the neuronal membrane.
Define transition and explain how it occurs
= where stimulated nocioceptors transmit impulses to the CNS by means of specalised sensory fibres. Nocioceptors terminate at the CNS so substance P is realised and picked up by opoid receptors on the other side of the synaptic clef at the dorsal horn neurons.
- from dorsal horn though spinal cord on asending tracts to the brain.
- the spinothalamic tract neurons carry implusles to the thalamus.
- Thalamus acts as a relay station sending the impulses to cnteral structures in the brain processing.
Define and describe perception
= the brain nociceptors input is perceived as pain.
This process involves may brain structures and there is no single precise ;ocation where it occurs.
Define and describe modulation
= neurons that chnage or inhibit nociceptive impulses such as endogenous opoids, serotonin and norepinerphrine (noradrenalise) resulting in modulation of pain signals.
The modulation occurs in the area of the dorsal horn. Previous experiences are one example of ways that can affect how pain is revoeced.
Outline a pain assessment/plan for acute pain
Initial assessment
Assessment tools
Goals of pain management
Ongoing assessment
Documentation
name one benefit and limitation of a pain assessment tool
+ quick
+ easy
+ relatively accurate
- one dimensional look at pain
- room for error
What are some key points of assessment for any pain?
- Definable injury / illness
- Definite onset
- Duration limited and predictable – usually subsides as healing occurs
- Associated with clinical signs of sympathetic
overactivity
What are 3 pain scores?
- numerical
- visual analogue
- instructs patient to point of a scale
- verbal rating
- descriptive
What is an example of a pain assessment tool for acute pain?
P = Provocation/Palliation
Q = Quality/Quantity
R = Region/Radiation
S = Severity Scale
T = Timing
What may be considered in a behaviours pain assessment tool?
- face
- restlessness
- muscle tone
- vocalisation
- consolability
Scored a 0-2 and equates to out of 10
What is a FAS score?
Description of limitation created by the pain.
e.g. move affected leg or take a deep breath and cough for thoracic injury
A – No limitation: the activity is unrestricted by pain
B – Mild limitation: the activity is mild to moderately restricted by pain
C ‐ Severe limitation: the ability to perform the activity is severely limited by pain
What are two points that may help differ acute to chronic pain?
- acute is shorter in nature and subsdes after healing
- acute has sympathetic symptoms e.g. increased HR and BP where as chronic will not
What are some key points of assessment of persistant pain that you may not assess for chronic?
- the labile nature it coming and going
- does it increase with activity for example?
- does pain wake them from sleep?
does it cause symptoms such as mood changes, lethargy, nausea
Explain BPI
Assesses pain severity and the degree of interference with function, using 0‐10 NRS
Assesses things like
- mood
- walking ability
Sleep
- relationship with others
enjoyment for life
- rating of pain severity out of 10
What are some good pain assessment tool for children?
- routine questions
- verbal scales
- numeric scales
- pictorial scales
What are some behavioural measures of pain?
- age related behavioural changes
- motor responses
- facial expressions
- crying
- behavioural responses (e.g. sleep‐wake patterns)
What are some physiological signs of pain?
- altered observations (HR, RR, BP, etc.)
- posture/tone
- sleep pattern
- skin colour/sweating
**not good indicators if in isolation
What is the QUESTT peads assessment tool?
Q: Question the child
U: Use a pain rating scale
E: Evaluate behavior & physiological change
S: Secure parents involvement
T: Take cause of pain into account
T: Take action and evaluate results
What is the FLACC peads assessment tool?
Faces
Legs
Activity
Cry
Consolability
What is McGills pain assessment? and what does it assess?
Persistent pain questionnaire
- sensory
- affecting
- total pain
What is brief assessment pain assessment? and what does it assess?
for persistent pain
- pain severity and effects of function
- 1-10
What is the behaviour pain assessment?
- for acute and persistent
- used when someone is in so much pain that they can communicate
Faces
Wrestlessness
muscle tone
vocalisation
confusability
What is the FLACC pead pain assessment
Face
Legs
Cry
Consulability
