Pain associated with head Flashcards
Idiopathic meaning
The cause is unknown. It will have the origin the same the condition. So, if there is an injury underlying the condition that will also be the reason of the pain state.
Trigeminal Neuralgia
A type of neuropathic pain around the face. This can rise from the injury of the trigeminal nerve/lingual nerve.
TMD and myofascial pain
Pain developed due to changes around muscle function in the face. E.g. TMD is associated with tightness around the muscle jaw. The tightness can also cause nerve pain.
Dental pain
Can be acute and chronic. It can also be nerve pain.
Where is the pain is recognised and localised?
Cortex
1st order afferents from the face…
Projects to pars interpolaris and pars caudalis of medulla /upper cervical cord.
2nd order neurones…
Ascend contralaterally to thalamic (via trigemino-thalamic tract)
3rd order neurones…
Project to cortex
Trigeminal system (5th cranial nerves)
1st order afferents -> 2nd order neurones -> 3rd order neurones
What is the underlying cause of migraine?
No injury but It is associated with inflammation and dilation within dura vessels and dura matter.
Migraine pathophysiology
- That localised inflammation will be associated with the release of the proinflammatory neuropeptides.
- This will lead to vasodilation of the dura blood vessels.
- Once it reaches the propagation threshold it will, propagate action potential.
- This will stimulate the nociceptors in the trigeminal nerve.
- Signal travels to the brain stem, then to thalamus, then to cortex.
What is the stimulation in the thalamus associated with?
Nausea and vomiting
What happened when the pain signal reached the cortex?
It is recognised and initiated (central pain processing)
What is the trigeminal nerve associated with?
Peripheral nerve processing
CSD
Cortical spreading depression, a slowly propagated wave of slowly propagated depolarisation that leads to depression of neuronal activity.
What is the main factor that tiggers migraine and headache?
CSD signal (Cortical spreading depression)
What does CSD signal stimulate? (1st)
Astrocyte activation
What does Astrocyte activation lead to? (2nd)
Trigeminal system activation and sensitization
What does Trigeminal system activation and sensitization lead to? (3rd)
Stimulation of trigeminal ganglion
What does Stimulation of trigeminal ganglion lead to? (4th)
Dura matter vasodilation and inflammation
What are the first 5 things in migraine pathophysiology known as?
Peripheral sensitization
Peripheral sensitization in migraine/headache pathophysiology (5)
- CSD signal (Cortical spreading depression)
- Astrocyte activation
- Trigeminal system activation and sensitization
- Stimulation of trigeminal ganglion
- Dura matter vasodilation and inflammation
What does peripheral sensitization in migraine/headache lead to? (5th)
Stimulation of trigeminal nerve
What does Stimulation of trigeminal nerve lead to? (6th)
Processing of the signal from the brain stem, to thalamus, to cortex.
Causes of headache 1 (arteries)
- Traction or dilatation of intracranial or extracranial arteries.
Causes of headache 2 (veins)
- Traction of large extracranial veins
Causes of headache 3 (cranial and spinal nerves)
- Compression, traction or inflammation of cranial and spinal nerves
Causes of headache 4 (cranial and cervical muscles)
- Spasm and trauma to cranial and cervical muscles.
Causes of headache 5 (Meningeal)
- Meningeal irritation and raised intracranial pressure
Causes of headache 6 (serotonergic projections)
- Disturbance of intracerebral serotonergic projections
What are important reports targeted for migraine?
Serotonin 5HT receptors
What is serotonin?
A neurotransmitter
Which two 5-HT receptors are involved in migraine?
7 and 2
What happens to serotonin level in the blood during migraine?
Low (Low pH)
Why is there a low threshold for migraine?
Due to unstable serotonergic neurotransmission
Sinus location
Usually behind forehead and/or cheekbones
Cluster location
In and around one eye
Tension location
Both sides, whole head and neck
Migraine location
One side of face (can swap between attacks)