Pain Assessment and Management + Chronic Pain Flashcards

1
Q

How is chronic cancer pain mediated?

A
  • Inflammatory signalling in tissue
  • stimulation and firing of pain receptors in periphery
  • Prolonged firing of nociceptive C-fibres
  • Pain signalling travels to spinal cord
  • First degree sensory neurons synapse
  • Central pathways carry signal to contralateral thalamus
  • Thalamic fibres project pain to every lobe of brain
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2
Q

List and describe an approach to pain assessment

A
  • Position
  • Quality
  • Radiation
  • Severity (clinical tools)
  • Timing
  • Understanding (meaning of pain)
  • Values (attitudes towards disease)
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3
Q

Describe common etiologies of pain

A
  • Nociceptive pain
    • Visceral pain (Peritoneum, pleural cavity)
    • Somatic pain (skin, muscle, bones, ligaments)
  • Neuropathic pain
    • Allodynia (perception of pain to non-painful stimuli)
    • Hyperalgesia (exaggerated pain response to painful stimuli)
    • Hyperpathia (altered pain perceptions)
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4
Q

Describe the WHO analgesic ladder

A
  1. Non-opioid +/- adjuvant
  2. Weak opioid +/- non-opioid +/- adjuvant
  3. Strong opioid +/- non-opioid +/- adjuvant
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5
Q

Opioid receptors

A
  • Mu Agonism
  • Delta
  • Kappa
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6
Q

Codeine

A
  • Weak opioid
  • naturally occuring opium alkaloid
  • pro-drug
  • converted to morphine in liver
  • 10% lack liver enzyme to convert to morphine (genetic polymorphism CYP2D6)
  • oral, parenteral, SR, combination with acetaminophen
  • q3-4h, 3-5 h duration
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7
Q

Tramadol

A
  • Weak opioid
  • Serotonin and NE reuptake inhibitors
  • oral, alone or combo with acetaminophen
  • CYP2D6 metabolism
  • Accumulation in renal and hepatic failure
  • Drug-drug interactions (SSRI, SNRI)
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8
Q

Morphine

A
  • Naturally occuring opium derivative
  • metabolized by liver, excreted by kidneys
  • M3G metabolite : no analgesia, neurotoxicity
  • M6G metabolite: analgesic, binds to u receptors
  • oral, SR, suppositories, IV.
  • Onset 45-60 minutes
  • Half life 4-6 hours
  • SR onset 3-4 hours
  • q8-12 hours
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9
Q

Hydromorphone

A
  • Semi-synthetic opioid
  • H3G : potent metabolite excreted by kidneys
  • Oral, CR, IV, rectal
  • highly soluble
  • q4h, 4-6h duration
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10
Q

Oxycodone

A
  • Semi-synthetic morphine cogener
  • Oxymorphone metabolite accumulates in Renal failure
  • q3-4h, 3-5 h duration
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11
Q

Fentanyl

A
  • Synthetic opioid
  • highly potent mu agonist
  • 100:1 morphine
  • no known active metabolites
  • Good in renal failure
  • Causes less constipation
  • Patch may not work in cachexia
  • lack of oral route, poor compliance, anxiety
  • DO NOT use conversion table when switching FROM fentanyl to morphine
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12
Q

Opioid dose equivalency table

A
  • Morphine 10 mg po
  • Hydromorphone 2 mg po
  • Oxycodone 5 mg po
  • Codeine 100 mg po
  • Tramadol 100 mg po
  • Fentanyl 25 ug/hour (see table)
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13
Q

Tolerance

A
  • Incomplete cross tolerance: unpredictable when rotating to different opioid.
  • Dose reduction 25-30%
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14
Q

Breakthrough dosing

A
  • Not predictable based on dose of regularly scheduled opioid
  • half of regularly scheduled dose or 10% daily dose
  • adjust with adjustment of regular dose
  • > 3 re-evaluation of regularly scheduled dose
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15
Q

Incident Pain

A
  • With movement that is not normally painful
  • Predictable
  • Try regularly scheduled dose pre emptively
  • Fentanyl sl, intranasal, sc, iv
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16
Q

Side effects of opioids

A
  • nausea and vomiting (attenuates after few days)
    • prokinetic antinauseant prn
  • Constipation
    • Durable SE
  • Sedation
    • attenuates
    • if persistent can rotate, opioid sparing adjuvants, interventional techniques, ritalin
  • Respiratory depression (narcosis)
    • aggressive titration
    • long acting used as breakthrough
    • multiple opioids
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17
Q

Naloxone

A
  • Central opioid antagonist
  • Reversal of respiratory depression and analgesia.
  • Raise RR without causing pain crisis
  • Small doses to avoid withdrawal
  • Goal is improvement of ventilation
  • Short half life 30-90 minutes, may need infusion if on long acting opioid.
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18
Q

Opioid intoxication (narcosis)

A
  • Altered mental status
  • Miotic pupils
  • Decreased bowel sounds
  • Low to normal heart rate and BP
  • Hypoventilation
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19
Q

Opioid narcosis management

A
  • If RR > 12 and 02 sat >90% RA, monitor
  • End tidal C02
  • If sat <90 and RR <12 but breathing spontaneously, give 0.04-0.05 mg naloxone IV/IM
  • If apneic, ventilate with BVM and give 0.2 to 1 mg naloxone IV/IM.
  • Infusion = 2/3 of total bolus doses given.
  • Goal of treatment is adequate ventilation, NOT mental status
  • Watch for withdrawal
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20
Q

Concerns about opioid addiction and tolerance in palliative care?

A
  • Addiction : psychological dependence where harms of use > benefits
  • Rare in patients with pain, with no hx of abuse
  • Tolerance : requirement of higher doses to manage same pain normal.
    • rotation, adjuvants
    • usually disease progression > tolerance
  • Physical dependence: normal with opioids.
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21
Q

Opioid rotation

A
  • change of route of administration (loss of oral route, delayed gastric empyting, bowel obstruction, delirium)
  • escalating pain not responsive to dose escalation
  • unacceptable side effects or neurotoxicity
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22
Q

Adjuvant analgesics

A
  • opioid sparing
  • improve side effects
  • neuropathic pain not as responsive to opioids
23
Q

Adjuvants: Dexamethasone

A
  • Useful for:
    • anti-inflammatory
    • headache/raised ICP
    • liver capsular pain
    • bone pain
    • neuropathic
    • retroperitoneal lymphadenopathy
  • < 24 mg /day
  • Long half life (36 hours); once daily dosing, but can split to reduce GI effects.

Side Effects:

  • altered glucose metabolism
  • insomnia
  • hypertension
  • truncal obesity
  • proximal muscle weakness
  • psychosis
  • infection (all and PJP)

Taper after 2 weeks (fatal delayed corticosteroid withdrawal sx)

PJP prophylaxis after 4 weeks

24
Q

Tricyclic antidepressants

A
  • absorbed small intestine, lipophilic, metabolism/elimination liver
  • decreased seizure threshold
  • QT prolongation ++ , ventricular dysrthythmias
  • first line for neuropathic pain
  • well tolerated, low doses work
  • anticholinergic SE (dry mouth, urinary retention, constipation, delirium)
  • Nortryptiline fewer SE
25
Q

Gabapentin/Pregabalin

A
26
Q

What factors are responsible for increased use of breakthrough dose?

A
  • Disease progression
  • Delirium/ opioid neurotoxicity
  • Psychosocial / spiritual distress
27
Q

Opioid induced neurotoxicity (OIN)

A
  • somnolence, vivid dreams
  • delirium, delusions, hallucinations
  • hyperalgesia / allodynia “pain all over”
  • myoclonus
  • seizures
  • dehydration, renal failure
  • Treatment:
    • dose reduction
    • hydration
    • opioid rotation
28
Q

Indications for Interventional analgesia

A
  • localized pain / dermatomal
  • uncontrolled pain
  • unacceptable side effects
29
Q

Managing a pain crisis

A
  • ruptured viscus
  • internal hemorrhage or tumour erosion
  • pathological fracture
30
Q

Chronic Pain definition

A
  • pain that persists beyond usual course of healing
  • associated with chronic pathological illness
  • continuous pain or recurs at intervals over months or years
31
Q

Total Pain

A
  • Physical, psychological, social, Spiritual
  • influence on experience of pain
32
Q

Nociceptive Pain

A
  • pain from actual or threatened damage to non neural tissue
  • activation of nociceptors
  • visceral or somatic
33
Q

Neuropathic pain

A
  • Pain from a lesion or disease of somatosensory nervous system
  • Peripheral or central
  • Quality:
    • numb
    • burning
    • allodynia
    • hyperalgesia
    • Dysesthesia (altered pain perception)
34
Q

Somatic pain

A
  • subtype of nociceptive pain
  • pain in skin, muscles, bones and joints
  • localized
  • sharp, throbbing, aching
  • agrravated by movement
35
Q

Visceral pain

A
  • subtype of nociceptive pain
  • injury of internal organs
  • poorly localized
  • aching, gnawing, cramping, pressure
  • referred pain
  • can have autonomic sx (diaphoresis, nausea)
36
Q

Pain History

A

OPQRSTUV

Onset

Provoking

Quality

Radiation

Severity

Timing

Understanding Impact

Value to patient

or SOCRATES

site, onset, character, radiation, associated factors, timing, exacerbating /relieving factors, severity

37
Q

Allodynia

A
  • painful response to NON PAINFUL stimulus
38
Q

Hyperalgesia

A
  • exaggerated response of pain to painful stimulus
39
Q

Hyperpathia

A
  • prolonged exaggerated response to painful stimulus
40
Q

Common Pain Scales

A
  • Intensity 0-10
  • Brief Pain Inventory
    • patient can complete
    • uses VAS
  • McGill Pain Questionnaire
    • self report tool
    • validated in cancer patients
41
Q

Chronic cancer pain

A
  • common as cancer treatments result in longer survival times
  • pain from cancer, surgery, chemo, steroids, hormones, radiation
  • Eg:
    • osteoporotic fractures
    • degenerative arthritis
    • avascular necrosis of femoral head
    • radiation fibrosis
  • Eg visceral pain syndromes
    • partial SBO from adhesions
    • odysnophagia from esophageal narrowing
  • Eg neuropathic
    • CIPN
    • scar pain
    • anything dermatomal
      *
42
Q

Chronic chemotherapy Peripheral neuropathy

A
  • stocking glove paresthesias/dysesthesia
  • Cisplatin, vincristine, paclitaxel, docetaxel
  • Tx:
    • acetaminophen, NSAID
    • SNRI
    • Anticonvulsant
    • TCA
    • topical agent
43
Q

Chronic pain from radiation

A
  • plexopathies
  • peripheral nerve entrapment
  • myelopathy
  • enteritis
  • proctitis
  • cystitis
  • osteoradionecrosis
  • osteoporosis
  • secondary malignancies
  • manifest months to years after radiation
44
Q

Chronic pain from hormonal treatments

A
  • Osteoporosis
  • cancer related bone loss is severe
  • increased fracture risk
  • avascular necrosis of hip
45
Q

Chronic pain from Head and Neck cancers

A
  • radical neck dissection
  • CN neuropathic pain
  • Shoulder Syndrome:
    • continuous pain
    • shoulder tilt and drop
    • limitations in shoulder retraction, anterior flexion, abduction
    • winged scapula
    • paresthesias and numbess CNXI damage
  • Osteonecrosis of mandible
    • radiation, chemo, steroids, bisphosphonates
46
Q

Chronic pain from rectal cancer

A
  • Pelvic Pain Syndrome:
  • Chronic radiation enteritis
    • crampy pain, tenesmus, bloody diarrhea, emesis
  • Chronic cystitis
    • irritation
    • urgency, dysuria
  • Pelvic insufficicency fractures
    • acute onset, intense somatic pain
  • Burning perineuom syndrome
    • perineal region burning
    • scrotum/vagina
    • rare, onset 6-18 months post radiation
47
Q

Chronic pain from sarcoma

A
  • Phantom limb pain
    • higher level of amputation, higher level of risk
    • days to weeks or months/years
  • Neuropathic pain
    • fatigue, stress, cold temperature, urination /defec all affect pain
    • Not psychological
48
Q

Chronic pain from prostate cancer

A
  • Osteoporosis
    • androgen deprivation therapy
    • decreased bone mineral density
  • Chronic testicular pain
    • chronic pelvic pain syndrome
    • Phantom testicular pain
49
Q

Chronic pain from breast cancer

A
  • Phantom breast pain
    • pressure, pain, numbness, tingling
    • can also occur even if breast reconstruction
  • Osteoporosis
  • Lymphedema
  • Neuroma
    • surgical scar on breast, chest, or arm
    • benign growth of nerve tissue, trapped in scar tissue
  • Intercostal brachial neuralgia
  • radiation induced
    • brachial plexopathy
  • Peripheral neuropathy
    • chemotherapy
    • vinca alkaloids
    • taxanes
    • platinums
  • Reconstruction/implants
50
Q

Chronic pain from lung cancer

A
  • Post thoracotomy pain syndrome
  • secondary intercostal nerve damage
  • ipsilateral arm and shoulder dysfunction
51
Q

Chronic pain with heme malignancies and stem cell transplants

A
  • Bone pain (Steroids)
  • Hemorrhagic cystitis
    • cyclophosphamide
    • radiation
  • Neurotoxicity from calcineurin inhibitors (tacrolimus)
    • tremor
    • insomnia
    • headache
    • vertigo
    • mood
  • Opportunistic infections
    • immunosuppression
    • eg herpes
52
Q

Non pharmacologic treatments for chronic pain in cancer survivor

A
  • multidisciplinary
  • Physician, PT, OT, SW, dietician, psychologist
  • Total pain?
  • exercise training
53
Q

Damocles syndrome

A
  • state of long term uncertainty, stress, anxiety of having a disease recurrence
  • impact of this fear on quality of life