Pain

Front 1

What are the classifications of pain based on the origin? Timing?

Back 1

Pain classifications based on origin:
o Somatic – or cutaneous skin, injury to the skin or to the body (well localized)
o Visceral – injury to the thoracic, pelvic or abdominal (poorly localized)
o Neurogenic or neuropathic – pain produced by damage to the nervous system or disorder in the nociceptive pathways.
Timing:
o Acute (limited and expected) or chronic (persists beyond healing)

Front 2

How can pain be assessed?

Back 2

Pain chart on history. 1 - 10, 10 being the worst pain of all.

Front 3

What is the guideline for pharmacological management of pain? Give examples.

Back 3

WHO stepladder.
Step 1 - aspirin, NSAIDs, paracetamol
Step 2 - codeine, oxycodone + adjuvant
Step 3 - stronger opioids: morphine, methadone, fentanyl

Front 4

What are the side effects of opioids? (3) NSAIDs and coxibs? (3) Paracetamol?

Back 4

Side effects of opioids:
o Sedation and respiration depression
o Nausea and vomiting
o Pruritus
NSAIDs and coxibs:
o Bleeding and clotting
o Renal dysfunction
o GIT ulceration
Paracetamol: hepatic dysfunction

Front 5

What are the 3 types of peripheral nociceptors and what are their characteristics?

Back 5

A beta - thickly myelinated
A delta - thinly myelinated
C - not myelinated

Front 6

Which horn do nociceptors neuron project into the spinal cord?

Back 6

They project into the dorsal horn of the spinal cord.

Front 7

Which lamina does each of nociceptors innervate?

Back 7

Aβ fibre – III to VI
Aδ fibre & C fibre – superficially I – II and smaller number reaching deeper lamina (V)

Front 8

What are the 2 nuclei in the spinal cord responsive to pain and where are they located?

Back 8

Nociceptive Specific (NS) cells – laminae I-II (Aδ fibre & C fibre)
Wide Range Cells (WDR) – lamina V (all 3 fibres, mostly Aδ fibre)

Front 9

What are the 2 ascending tracts? Where do they origin and terminates?

Back 9

1. Parabrachial pathway
• Lamina I-II to PB, limbic system and PAG area of the brain
2. Spinothalamic tracts – lamina V to thalamus
• Lateral (paleospinothalamic tract)
o To
 limbic system (emotion aspect)
 post-central gyrus (location)
 reticular formation (wake up at night)
 medulla oblongata (HTN, tachycardia, tachypnoa)
• Anterior (neospinothalamic tract)
o To post-central gyrus (location)

Front 10

What is the function of the descending pathway?

Back 10

Function of descending pathway: to dampen down the pain sensation

Front 11

What are the 3 types of endogenous analgesics?

Back 11

3 endogenous opioids: endorphins, enkephalins, dynorphins.

Front 12

What is the mechanism of action of opioid?

Back 12

o Post-synaptically: Increase potassium influx – hyperpolarisation
o Pre-synaptically: Inhibit calcium channel – inhibit NT release into the synaptic cleft.

Front 13

How can the effect of opioids be reversed?

Back 13

Naloxone.

Front 14

What are the 2 major descending pathways?

Back 14

2 major descending pathways:
o Serotonergic - Activated by or capable of liberating serotonin
o Adrenergic - Activated by or capable of releasing epinephrine