Anaesthetics - Pain and Pain relief

Question 1

what is nociceptive pain?

Answer 1

Obvious tissue injury or illness, Also called physiological or inflammatory pain, Protective function. Sharp ± dull. Well localised

Question 2

What is neuropathic pain?

Answer 2

Nervous system damage or abnormality. Tissue injury may not be obvious. Does not have a protective function. Burning, shooting ± numbness, pins and needles. Not well localised. Abonrmal processing of thhe pain signal

Question 3

give examples of neuropathic pain

Answer 3

Nerve trauma, diabetic pain (damage), Fibromyalgia, chronic tension headache (dysfunction)

Question 4

what are pathalogical mechanisms of nneuropathic pain?

Answer 4

increased receptor numbers, abnormal sensation of nerves, chemical changes in the dorsal horn, loss of onrmal inhibitory modulation

Question 5

along what types of fibres does pns signals travel along?

Answer 5

Ab and C

Question 6

what tract does pain travel along?

Answer 6

Spinothalamic

Question 7

where in the brain does pain perception occur?

Answer 7

cortex

Question 8

how is pain modulated?

Answer 8

gate theory of pain modulation. As well as a descending pathwy form the brain to the dorsal horn

Question 9

name simple analgesics

Answer 9

paracetamol (acetaminophen), Non-Steroidal Anti-inflammatory drugs, Diclofenac, ibuprofen

Question 10

name opioids

Answer 10

Mild - Codeine, Dihydrocodeine. Strong - Morphine, Oxycodone, Fentanyl

Question 11

other analgesics

Answer 11

tramadol, nefopam, amitriptyline, gabapentin, Ketamine,

Question 12

Peripeheral tx…

Answer 12

rest, ice, compression, NSAID’s

Question 13

Spinal cord tx…

Answer 13

opioids, ketamine.

Question 14

Brain tx…

Answer 14

paracetamol, opioids, amittiptyline,clonidine

Question 15

ADX and DISADX of Paracetamol

Answer 15

cheap, safe, can be givenn orally, rectally or by iv, good for mild pain. May cause Liver damage.

Question 16

ADX and DISADX of NSAID’s

Answer 16

Advantages - Cheap, generally safe, Good for nociceptive pain, Best given regularly with paracetamol (Synergism)
Disadvantages - Gastrointestinal and renal side effects plus cause bronchospasm in sensitive asthmatics

Question 17

ADX and DISADX of Codeine

Answer 17

Advantages - Cheap, safe, Good for mild-moderate acute nociceptive pain, Best given regularly with paracetamol
Disadvantages - Constipation, Not good for chronic pain

Question 18

ADX and DISADX of Tramadol

Answer 18

Weak opioid effect plus inhibitor of serotonin and noradrenaline reuptake (modulation)
Advantages - Less respiratory depression, Can be used with opioids and simple analgesics, Not a controlled drug
Disadvantages - Nausea and vomiting

Question 19

ADX and DISADX of Morphine

Answer 19

Advantages - Cheap, generally safe, Can be given orally, IV, IM, SC, Effective if given regularly, Good for: Mod-severe acute nociceptive pain (e.g. post-op pain), Chronic cancer pain
Disadvantages - Constipation, Respiratory depression in high dose, Misunderstandings about addiction, Controlled drug, Oral dose is 2-3 times IV / IM / SC dose

Question 20

ADX and DISADX of Amitriptyline

Answer 20

Tricyclic antidepressant (TCA) - Increases descending inhibitory signals
Advantages - Cheap, safe in low dose, Good for neuropathic pain, Also treats depression, poor sleep
Disadvantages - Anti-cholinergic side effects (e.g. glaucoma, urinary retention)

Question 21

ADX and DISADX of Anti-convulsants

Answer 21

Examples - Carbamazepine (Tegretol), Sodium valproate (Epilim), Gabapentin (Neurontin)
Also called membrane stabilisers, Reduce abnormal firing of nerves, Good for neuropathic pain

Question 22

WHO pain ladder for Nociceptive pain…

Answer 22

Mild - Paracetamol (± NSAIDs)
Moderate - Paracetamol (± NSAIDs) + codeine/ alternative
Severe - Paracetamol (± NSAIDs) + morphine

Question 23

for neuropathic pain which drugs are usually used?

Answer 23

Amitriptylline, Gabapentin, Duloxetine

Question 24

nociceptive and neuropathic pain tx overview…

Answer 24

noci - use WHO pain ladder, neuro - use alternative analgesia, not responsive to WHO pain ladder drugs.

Question 25

RAT approach to pain…

Answer 25

recognise, assess (severity, type, other factors), treat.

Question 26

nonsurgical tx…

Answer 26

RICE, Nursing care, Surgery, acupuncture, massage, TENS etc, Psychological, Explanation and reassurance, Input from social worker / pastor

Question 27

what is RICE?

Answer 27

Rest, ice, compression, elevation of injuries