7: Pain

Question 1

Pain

Answer 1

unpleasant sensory/emotional experience associated with/resembling that associated with, actual or potential tissue damage
No brain, no pain!

Question 2

Types of pain

Answer 2

• Nociceptive: (epicritic/neuropathic) (warning us from a noxious stimulus. Motor reflexes to escape stimuli will follow)
- epicritic: transmitted via delta fibres: sparsely myelinated, large-diameter, fast-conducting -> sharp, well-localized pain
- Protopathic: transmitted by C fibres: unmyelinated, small-diameter, slow-conducting -> poorly localized, dull, aching pain

• Neuropathic: damage of nerves in peripheral/central nervous system

• Nociplastic: weder Nerven noch tissue beschädigt, wahrsch. durch lowering of pain threshold, nicht kaputte Nerven (zb migrain)

Question 3

Pain classification

Answer 3

1. Physiological nociceptive pain
   • Pain is elicited by nociceptive stimuli, warning us from a noxious stimulus
2. Pathophysiological nociceptive pain
   • Pain is elicited by pathophysiological processes in organs (e.g. inflammation) -> warning sign of disease. Elicits responses that may facilitate healing (e.g. keeping still)
3. Neuropathic pain
   • Pain is elicited by injury to a nerve (nervous structure). «Abnormal» (no warning sign for an actual nociceptive stimulus).
4. Psychogenic pain
   • Pain is elicited by mental, emotional, or behavioral factors

Question 4

Clusterheadaches

Answer 4

Primary Headaches
Delta fibres

• excrutiating pain, like knife in head
• strictly unilateral
• lasts 15 - 180 min
-> pain killers dont work are too slow
-> O2 helps
• mostly at night (afraid of going to sleep)
• Often spring/autumn
• Occurs in bouts (6-8W täglich, dann lang nicht mehr zb)
• running nose/tearing on one side
• Horner‘s Syndrome: smaller pupil on ache side: lesion of sympathetic nervoussystem? Nervous fibres get pressed into head

Question 5

Trigeminal autonomic reflex

Answer 5

• Hypothalamus, Makes very aggressive -> Aggressions Zentrum?, also inner clock
• Activation of facial nerve -> production of neurotransmitter (&CGRP) -> lowers painthreshold -> more pain -> more NT -> pain increases in first 8min
• Cutting trigeminal nerve doesnt help -> blind and pain still there
• O2 helps
• Alcohol helps
• Electric stimulation of sphenopalatine ganglion helps
• Today: research in genetics

Question 6

C fibres in primary headaches:

Answer 6

• migraine
• Feels like internal pain -> like infection -> brain makes us want to lie down
• Peripheral sensitisation
• Release of CGRP (lowers pain threshold) -> CGRP blockers help (doesnt help with Mens migraine)
• Aura: changes over time, cortical spreading depression (CSD)

Question 7

Primary Headaches

Answer 7

Migraine
Tension Type Headache
Cluster / trigemino-autonomal Headaches

Question 8

Neuropathic pain:

Answer 8

• nerve lesions eg. due to MS / stroke

Trigeminal Neuralgia: Recurrent paroxysms of unilateral facial pain, Precipitated by innocuous stimuli within the affected trigeminal distribution

• nerve-vessel-contact: artery too close to nerve -> can be operated -> myelin can grow back

• Conduction block: myelin gone -> nociceptors dont have myelin -> work without it -> ignition theory; continue firing trotz block -> spontaneous activation

Question 9

Tension Type Headache:

Answer 9

• just pain, bilateral
• Nicht soo schlimm aber nervig
• Treatment: muscle triggerpoints: verstärkte Drucksensibilität, zentrale Sensibilisierung
• Nicht soo häufig in europe, wenig treatment Möglichkeiten (Antidepressants)