Clinical Lecture: Pain

Question 1

What is a Congenital Insensitivity to Pain?

Answer 1

Congenital insensitivity to pain is a condition that inhibits the ability to perceive physical pain. From birth, affected individuals never feel pain in any part of their body when injured. These children cannot learn which damage is dangerous - this leads to bone fractures and blisters. Education is harder. These children need constantly attention. If they are not educated to properly take corer of themselves, they tend to die early to due to multiple external and internal injury.

Question 2

Why is a sharp pain followed by a dull ache in a noxious stimulus e..g stepping on a Lego?

Answer 2

Different fibres convey different aspects of pain sensation. A-Delta fibres are faster conducting fibres. They mediate 1st pain. This is interpreted as sharp but it dissipates quickly.
E.g. when standing on a Lego, the sharp pain is replaced by a dull ache. This is slowly replaced by a dull ache - which is a slow C-fibres. It is less well defined.

Question 3

Give an example of channels expressed exclusively/preferentially in nociceptors?

Answer 3

• Nav1.7, Nav1.8 and Nav1.9
• sensory receptors such as TRPV1, TRVM8 and TRPA1
• Puringetic ligand gated channels such as P2X2 and P2X3 - activated by tissue damage to due the lease of ATP

Question 4

What are the different types of inflammatory mediators?

Answer 4

• Those that act directly activate ligand-gated ion channels such as ATP and protons
• Those that activate G-proteoin coupled receptors such as Prostaglandins, Substance Pm Bradykinin, Histamine and Proteases
• Those that activate receptor tyrosine kinase - NGF, BDNF
• Gasotransmitters such as CO, NO H2S

Question 5

What role does sensory connections to the Amygdala allow?

Answer 5

Emotional component of pain

Question 6

What is the Gate Control Theory of Pain?

Answer 6

Thegate control theory of painasserts that non-painfulinput closes the nerve “gates” topainfulinput, which preventspainsensation from traveling to the central nervous system.

In severe stress, many soldiers can continue fighting even though severely wounded. They may not even noticed, they feel no pain. The next day/week later, they are completely different. The inhibition is removed and may even complain of a needle. The shut down is no longer there.

In put form mechanoreceptors e.g. massaging a sore shoulder can help. You can therefore produce a degree of alleviation.

Question 7

What is central sensitisation?

Answer 7

Central sensitization refers to the process through which a state of hyperexcitability is established in the central nervous system, leading to enhanced processing of nociceptive (pain) messages.

Question 8

Describe an example to familial cause of migraine.

Answer 8

• Familial hemiplegic migraines - an AD subtype of severe migraine accompanied by aura
• Aura caused by cortical spreading suppression - slowing advancing waning of depolarisation the cortex
• More than half of FHM are caused by mutations in a voltage gated calcium channel
• This leads to increase calcium flow into dendoroyesz and excessive release of the excitory neurotransmitter glutamate