Pain and its Management Flashcards
Analgesia
Inability to feel pain
What nerve ending is nociceptors?
Free nerve endings
Which fibres are responsible for fast response to pain?
Describe what they look like?
For what pain?
A delta fibes
Large, myelinated
up to 10m/sec
Sharp, stabbing pain
Which fibres are responsible for slow response to pain?
Describe what they look like?
For what type of pain?
C fibres
Small, unmyelinated
1.2m/sec
Which tract conducts pain?
Lateral spinothalamic tract
Is the pre-central gyrus sensory or motor?
Motor
Is the post-central gyrus sensory or motor?
Sensory
Where can local anaesthetic be administered?
At site of injury
Peripheral nerve
Spinal epidural
Where do NSAIDs take action?
At cortex
Site of injury
Role of PGE2
Pain sensitisation
Renal arteriole dilation
Ductus arteriosus patency
Cervix relaxation
How are prostaglandins produced?
Phospholipid goes to arachadonic acid (help of phospholipase)
Arachadonic acid goes to prostaglandin (help of cycle-oxygenase)
Prostaglandin H2 goes to prostaglandins (help of PG synthase)
Role of PGF2alpha
Bronchoconstriction
Uterine contraction
Role of PGI2
Vasodilation
Inhibition of platelet aggreagation
What does cox-1 do?
In background all time
Gastric protection
Platelet aggregation
Renal protection
What does cox-2 do?
Inflammation
Hyperalgesia- increased sensitivity to feeling pain
What do NSAIDS inhibit?
Cyclo-oxygenase
No prostaglandlinH2 so no prostaglandins produced
Where do opioids act on?
Act on brain- how brain perceived pain (strongest)
Also site of injury- weakest
Spinal epidural can be beneficial - middle effectiveness
Name opioids that are naturally occurring?
Morphine + Codeine
What are prodrugs?
Metabolised in body into active drugs
What are endogenous opiods?
Body’s own analgesics
Can be produced during exercise
Signalling processing of pain
Delta fibre/C fibre enter posterior horn
Form synapse with neurone which takes info across contralateral side up to thalamus
Endorphins create negative control (from interneurone)
Endorphins will inhibit pathway at the synapse
When rub yourself give rise to mechanoreceptor stimulation and activation of neurone that releases endorphins and so inhibit red pathway
What does acupuncture do?
Active mechanoreceptors release endorphins
What is patient controlled analgesia?
Allow patient to regulate analgesic dosing schedule
Anaesthetist set lock mechanism so there is a max so no overdose
What are analgesics?
Class of medications to relieve pain
