Pain Flashcards

1
Q

What is pain

A

Unpleasant sensory and emotional experience

Associated with actual or potential tissue damage

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2
Q

What are simple analgesics

A

Paracetamol

NSAID

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3
Q

What are opioids

A
Codeine 
Dihydrocodeine
Co-codomol (8/500 or 30/500) or codydramol
Morphine
Oxycodone
Fetanyl
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4
Q

What are other options for pain relief

A
Tramadol - small opiate + 5HT / NA reuptake inhibitor 
TCA 
Anti-convulsants
Ketamine - NMDA receptor antagonist 
LA
Nerve block 
Spinal and epidural 
Topical - capsaicin
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5
Q

Action of paracetamol

A

Inhibits prostaglandin synthesis

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6
Q

What is it good for

A

Mild pain
Very effective with NSAID
Severe pain in combination with other drugs

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7
Q

SE

A

Almost none
Very cheap and safe
Liver damage in overdose so caution in impairment

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8
Q

How is it given

A

Oral
Rectal
IV - adjust dose according to weight

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9
Q

Action of NSAID (Ibuprofen / Aspirin / Diclofenac)

A

Inhibit enzyme cyclo-oxygenase which is used in prostaglandin and thromboxane synthesis

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10
Q

What are NSAID good for

A

Nociceptive pain

In combination with paracetamol

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11
Q

When do you have caution with NSAID

A
GI pathology - peptic ulcer
Bleeding / anti-coagulation 
Impaired renal
Sensitive asthmatics
Elderly 
Aspirin CI in children due to risk of Reye's
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12
Q

What do opioids do and how do you give

A

Act peripherally and centrally at opioid receptor to inhibit transmission off pain (analgesia)
Can give by all route but must convert dose

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13
Q

What are the SE of opioids

A

Resp depression as decreased sensitivity to CO2
N+V so give with anti-emetic
Constipation - decreased motility
Miosis

Other 
Headache 
Urinary retention 
Bradycardia
Hallucination 
Sedation

Release of Histamine

  • Bronchospasm
  • Hypotension (vasodilation)
  • Itch and wheels
  • Phlebitis

Endocrine

  • Inhibition of ACTH / prolactin / FSH / LH
  • Increased ADH
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14
Q

Why are opioids controlled drugs

A

Due to addictive nature

Risk of tolerance and dependence

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15
Q

What is morphine useful for

A

Moderate - severe acute nociceptive pain I.e. hip fracture
Give 10mg IV
Chronic cancer pain

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16
Q

What are disadvantages of morphine

A

Significant first pass metabolism
COnstipation
Resp depresion
Addiciton

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17
Q

What should oral dose of morphine be compared to IV

A

3x larger

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18
Q

What is codeine good for

A

Mild-moderate acute nociceptive pain

Best given regularly with paracetamol

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19
Q

What is codeine not good for

A

Chronic pain

Cause constipation

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20
Q

What is tramadol and how does it act

A

Weak opioid plus inhibitor of serotonin and Na reputake

Acts at spinal cord to dampen pain transmission

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21
Q

Benefits of tramadol

A

Less resp depression
Can be used with other opioids and simple analgesia
Not a controlled drug - now controlled

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22
Q

When do you use

A

NO justification as first line unless other opioid CI

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23
Q

Disadvantages

A

N+V
Caution in epilepsy as lower seizure
Caution if use with TCA / SSRI as lower seizure

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24
Q

How does amitriptyline (TCA) work

A

Increases descending inhibitory signals

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25
Q

What is it good for

A

Neuropathic pain

Depression / poor sleep

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26
Q

Disadvantages

A

Anti-cholinergic SE

  • Glaucoma
  • Urinary retention so do not give if BPH
  • CI MG
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27
Q

What anti-convulsants are useful for pain and what role

A

Gabapentin / Pregabalin = 1st line
Carbamazepine
Sodium valproate

Membrane stabiliser so reduce abnormal firing of nerves
Good for neuropathic pain

28
Q

What are 4 steps of pain transmission

A

Periphery
Spinal Cord
Brain
Modulation

29
Q

What happens at periphery

A

Tissue injury
Release of prostaglandin / substance P
Stimulation of pain receptors
Signal travel in nerves

30
Q

What nerves carry pain

A

A delta

C

31
Q

What happens at spinal cord

A

Nerves synapse
Cross over
Travel up opposite site to brain

32
Q

What happens in brain

A
Synapse in thalamus
Connect to many part of brain
Cortex = perception
Limbic
Brain stem
33
Q

What is modulation

A

Descending pathway from brain to dorsal horn which usually decreases pain signal

34
Q

Gate theory of Pain

A

Distractive stimulus blocks pain fibres from going to brain

35
Q

What are pathological mechanisms which can lead to increases pain

A

Increased receptor number
Abnormal sensitisation
Chemical changes in dorsal horn
Loss of normal inhibitor modulation

36
Q

How can you classify duration of pain

A

Acute
Chronic
Acute on chronic

37
Q

Acute pain

A

Recent onset

Usually nociceptive

38
Q

Chronic pain

A

> 3 months
After normal healing
Often no identifiable cause

39
Q

How do you classify mechanism of pain

A

Nociceptive

Neuropathic

40
Q

Nociceptive pain

A
Due to stimulation of pain receptor
Obvious tissue injury or illness
Protective 
Sharp +- dull
Well localised
41
Q

Neuropathic pain

A
Caused by primary lesion or dysfunction of nervous system
Leads to abnormal processing 
Injury may not be obvious 
No protective function
Burning / shooting / pins and needles
42
Q

How do you manage pain at periphery

A

RICE
NSAID
LA

43
Q

How do you manage pain at spinal cord

A
Acupuncute
TENS
LA
Opioids
Ketamine
44
Q

How do you manage at brain

A

Psychological
Opioids
Amitryptilline
Paracetamol

45
Q

What are non-drug Rx

A
RICE
Surgery
Acupuncture
Physio
TENS 
Psychological 
Nerve block 
Fracture fixation
46
Q

What should pharmacological Rx be

A
High enough to control 
Flexibility to allow for fluctuation
Avoid SE
Polymodal as synergistic 
Oral where possible
47
Q

What do you do for acute pain

A

WHO pain ladder

48
Q

What do you do for neuropathic pain

A

Alternative - TCA / anti-convulsant
Psychological
Non-drug

49
Q

What do you do for mild pain on ladder

A

Non-opioid
Paracetamol
+- NSAID

50
Q

What do you do for moderate

A

Paracetamol +- NSAID
+ mild OPOID
Start with codeine then dihydrocodeine - usually 30
Co-codomol (paracetamol 500+codeine 10)
Co-dydromole (paracetnaol 500 + dihydrocodeine 10)

51
Q

What do you do wfor severe

A

Paracetamol +-NSAID
+ Strong opioid - Morphine
Miss out middle

52
Q

What do you do as pain resolves

A

Move down ladder

Continue bottom layer

53
Q

What is RAT approach

A

Recognise pain
Assess
Treat
Reassess

54
Q

How do you assess pain

A

Severity
Pain score - rest and movement
Type of pain - acute / chronic / cancer / nociceptive / neuropathic
Other factor

55
Q

What other factors affect

A

Physical - other illness
Psychological - anger / anxiety / depression / support
How is it affecting patient

56
Q

How can pain relief be given

A
Oral
Rectal
Inhalation - entonox 
Sublingual
SC
Transdermal
IM
IV - bolus vs PCA
Epidural
57
Q

What is an epidural

A

LA + opioid into epidural space

58
Q

How can LA be administered

A
Local infiltration
Epidural + opiate
Intrathecal + opiate
Wound catheter
Nerve plexus catheter
59
Q

What should you always investigate

A

Unexpected level of pain
Pain suddenly increasing
Pain associated with change in vital signs

60
Q

How can you assess pain

A
Verbal - on rest and movement 
Numerical
Visual analogue
Siling face
Abbey pain
61
Q

What do you do if opiate addicted

A

Contact pain team or drug and alcohol nurse

Nerve block instead ?

62
Q

When is spinal analgesia good

A

Surgery in lower half of body

63
Q

What is preferred option post-abdominal

A

Epidural

Helps prevent post - op resp compromise due to pain and constipation from drugs

64
Q

What is PCA

A

Patient controlled

Morphine usual drug of choice

65
Q

What is 1st line neuropathic

A

Amityptline or pregabalin or Gabapentin

66
Q

2nd line

A

Both
Refer to pain sepicalist
Tramdaol in interim