Pain Management

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Pain Management

• Kara Fereday
• Lecturer/Practitioner Palliative Care

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Physiology of Pain

• The International Association for the Study of
  Pain (1979) define pain as unpleasant sensory
  and emotional experience, associated with actual
  or potential tissue damage.
• Sofaer (1992) believes that because of its
  subjective nature pain can only properly be
  defined by the patient.

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Nociceptive Pain

• Transduction, Transmission, Perception
  Modulation
• Transduction of Pain
• Occurs when nociceptors respond to noxious
• stimuli.
• Where are they?
• Nociceptors located in nerve endings of C
• Alpha delta fibres.

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Different Nerve Fibres

• Alpha delta Fibre (fast)
• Myelinated, conducts sensations of sharp pain.
• C Fibres (slow)
• Unmyelinated, interpreted as a dull ache.
• Alpha beta Fibre (fast)
• Touch receptors

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How? When noxious stimuli occurs
neurotransmitters and molecules
released. Prostaglandins, Bradykinin, Serotonin,
Substance P and Histamine. Causes the dendrites
to transmit pain impulse, which is passed down
axon to axon terminal.
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• Transmission of Pain
• Pain signal travels from site of transduction
  along nociceptive fibre to dorsal horn of spinal
  cord.
• From spinal cord to brainstem
• Through thalamus and higher levels of the brain.

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• How?
• C Alpha delta fibres terminate in dorsal horn
  after transmitting impulses via synaptic cleft.
• More neurotransmitters released then pain impulse
  transmitted from spinal cord to brain stem and
  thalamus via ascending pain pathways.

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• Perception of Pain
• Pain now a conscious experience, activating
  multiple areas within the brain.
• Somatosensory Cortex identifies location and
  type of pain
• Limbic System responsible for emotional
  behaviour
• Reticular System alerts individual to the pain

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• Modulation of Pain
• Involves stopping or changing pain impulses.
• Involves fibres that originate in brain stem
  which descend to dorsal horn. These fibres
  release neurotransmitters that stop transmission
  of pain impulses and produce endogenous opiods.

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• Transduction
• Transmission
• Perception
• Modulation

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Gate Theory

• Malzack Wall (1965)
• The theory suggests the existence of a pain
  gate in the dorsal horn of the spinal cord.
• Small nerve fibres carry pain stimuli through a
  gate mechanism. Large nerve fibres travelling
  through the same gate can inhibit the smaller
  nerves carrying the pain signal.
• Large nerve fibres are the touch receptors, Alpha
  beta fibres.

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Gate Theory

• This leads to the theory that pain signals can be
  altered by stimulating the periphery of a pain
  site.
• Pain gate can be shut by stimulating touch
  signals through massage, rubbing, wheat bags.
• Gate can also be shut by endogenous opiods, via
  acupuncture, TENS.

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Stop !

• Name the four areas involved in nociceptive pain
• Transduction
• Transmission
• Perception
• Modulation

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Think about..

• Incidents where you cared for a patient who
  required pain control
• What happened?
• What factors influenced you clinical decision?
• Do you have any fears or frustrations when
  providing effective pain assessment and
  management?

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Types of Pain

• Somatic
• Visceral
• Referred
• Bone
• Neuropathic
• Emotional/Spiritual

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Types of Pain

• Somatic
• Skin, Muscle, Joints, superficial or deep.
• Visceral
• Organs of Thorax Abdominal Cavity, dull ache,
  burning, sensation. Usually as a result of
  stretching, infiltration and compression

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Types of Pain

• Both Somatic Visceral pain travel along the
  same pathways. Pain stimuli arising from the
  viscera is perceived as somatic in origin.
• This can be confused by the brain and is often
  described as referred pain.

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Liver
Liver
Heart
Stomach
Gallbladder
Small Intestine
Ovary
Colon
Appendix
Kidney
Right Ureter
Bladder
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Types of Pain

• Bone Pain
• Poorly localised, aching, deep, burning.
• Common with Breast, Lung, Prostate, Bladder,
  Cervical, Renal, Colon, Stomach and Oesophagus
• Can lead to pathological fractures.
• Vertebral Metastases can lead to cord compression.

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Bone Pain

• Osteoblasts, Osteoclasts and Osteocytes are
  involved in remodelling bone.
• In healthy individuals bone remodelling is
  carefully regulated.
• Normally Osteoblasts replace the same amount of
  bone which has been resorbed by the Osteoclasts.
• In malignancy process not balanced, resulting in
  a loss of bone mass.

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Types of Pain

• Neuropathic Pain
• Caused by disturbance of function or pathological
  changes in a nerve.
• May arise from a lesion or trauma, infection,
  compression or tumour invasion.
• Described as burning, shooting, tingling.
• Does not respond well to standard analgesics.

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Neuropathic Pain

• Abnormal Sensations
• Hyperaesthesia - an increased sensitivity to
  stimulation.
• Hyperalgesia increased response to a stimulus
  that is normally painful.
• Allodynia pain caused by a stimuli that is not
  normally painful

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• Neuralgia
• Pain in the distribution of the nerve, lancing,
  shooting, jumping, electricity.
• Parasthesia
• An abnormal sensation, tingling, pins and
  needles.
• Tight Feeling
• Vice like tightness, gripping, cramping.

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Types of Pain

• Emotional/Spiritual Pain
• Subjective
• Fear of unknown
• Eclectic Holistic

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Pain Assessment

• Pain History
• The site of pain
• Type of pain
• Exacerbating Relieving factors
• How frequently
• Impact on daily life
• Previous therapies

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Pain Assessment

• Factors to Consider
• Mood
• Non Verbal Communication
• Environment
• Ethnicity

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Concerns Misconceptions

• Pain is inevitable.
• If the pain is worse, my cancer is spreading.
• I should wait until I really need my pain killer,
  before I take it.
• If I take Morphine I will die soon.
• I will get addicted to pain killers.

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Analgesics
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• Mike

• Rachel

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Opiod for moderate To severe pain non
opioid /- Adjuvant
Opiod for mild to Moderate pain Non opioid /-
Adjuvant
Non Opioid /- Adjuvant
Pain
Pain
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Adjuvant Analgesia

• Drugs which are not analgesics in their own right
  and are primarily used for other purposes.
• Adjuvant drugs are used in combination with drugs
  from all steps of analgesic ladder.

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Adjuvant Analgesia

• Antidepressants useful for aching, burning and
  neuropathic pain.
• Amitriptyline, Dothiepin.
• Alter neurotransmitter at synapse.
• Anticonvulsants neuropathic pain.
• Carbamazapine, Sodium Valporate, Clonazepam and
  Gabapentin, Pregabalin.

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Stabilises excitable cell membrane useful for
shooting pain. Used in conjunction with
antidepressant. Ketamine anaesthetic which has
analgesic properties at sub anaesthetic dose.
Act on receptors in spinal cord.
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Adjuvant Analgesia

• Steroids inflammation, tumour oedema.
• Dexamethasone, Prednisilone.
• 7mg Prednisilone 1 mg Dexamethasone
• Antispasmodics - Colic
• Baclofen, Buscopan.

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Stop !

• Which of the following would you consider to be
  adjuvant medication
• A medication thats not usually used primarily as
  a painkiller
• Medication with added fruit juices
• Paracetamol
• Medicine made in France

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Non opiod Mild opiod

• Non Opiod
• Paracetamol, Aspirin, NSAID ie, Voltarol,
  Brufen, Arthrotec, Celocib.
• Opiod for Moderate Pain
• Codydramol, cocodamol Tramadol, codeines.

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Moderate/Severe Pain

• Morphine, MST, Zomorph, Oromorph.
• Diamorphine s/c
• Palladone (hydromorphone)
• Oxycodone, Oxycontin, Oxynorm
• Methadone
• Fentanyl Patches
• Buprenorphine Patches (Transtec)

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Side Effects

• Drowsiness
• Respiratory Depression
• Over Dose
• Nausea
• Constipation
• Myoclonic Jerking
• Skin Reaction

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Non Pharmacological

• DXT
• Nerve Blocks
• Tens
• Complementary Therapies
• Acupuncture
• Information

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Decision Making

• When to go up analgesic ladder?
• Sensitivity
• Social Situations
• Constipation PMH
• Compliance

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Common Conversions

• Morphine to Diamorphine
• Morphine 24hr dose - 3
• MST 60 mg BD 120 mg (24 hrs) - 3
• 40 mg Diamorphine (24 hrs)
• Diamorphine to Morphine
• 24 hr Diamorphine X 3
• Diamorphine 20 mg X 3 60 mg MST - 2
• 30 mg BD.

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Conversions

• Morphine PO Diamorphine S/C
• 31 ratio
• (divide 24hr morphine by 3)
• Morphine PO Morphine S/C
• 21 ratio
• (divide PO morphine by 2)

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Conversions

• PO Morphine Oxycodone S/C
• 21 ratio (palliative drugs)
• 31 ration (DH)
• (divide by 2 or 3)
• Oxycodone PO Oxycodone S/C
• 32 ratio
• (divide Po by 3 and multiply by 2)

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Conversions

• Diamorphine S/C Morphine S/C
• 23 ratio
• (divide diamorphine by 2 and multiply by 3.)
• Diamorphine S/C Oxycodone S/C
• 23 ratio (Palliative drugs)
• 11 ration (DH)

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Common Conversions

• Tramadol
• Total Tramadol Dose - 5 24 hr MST
• 300 mg - 5 60 mg - 2 BD MST 30 mg
• Codeine 10mg 1mg Morphine

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Breakthrough Doses

• Morphine - 6 Breakthrough dose
• Eg 60 mg - 6 10 mg
• Diamorphine - 6 Breakthrough dose
• Fentanyl as conversion chart
• Convert to Morphine before converting to
  Diamorphine.

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How did you do?

• 1. Codeine, Dihydrocodeine, Tramadol.
• 2. 40 mg
• 3. Anti convulsants, anti depressants, topical
  opioids, steroids.
• 4. Give MST and put patch on at same time.
• 5. 200mg