Facial Pain - Neuralgias Flashcards
what are the 3 sensory branches of CN5?
ophthalmic (V1), maxillary (V2), and mandibular (V3)
where does V1 go through?
superior orbital fissure
where does V2 go through?
foramen rotundum deep in skull to pterygopalantine fossa
where does V3 go through?
foramen ovale into the infratemporal fossa (also supplies non-taste sensation to anterior 2/3 of tongue)
what is the CN5 motor branch?
axons travel with V3 to ipsilateral muscles of mastication (nucleus lies medially to sensory nucleus)
what are the first order neurons for CN5 and where do they converge?
V1, V2, V3 - converge at trigeminal ganglion (gasserian or semilunar) at apex of petrous temporal bone in a depression (meckel’s cave) lateral to cavernous sinus in middle cranial fossa
where do the 2 pathways for the second order neurons converge from the brainstem?
in the thalamus
what are the 2 nuclei for the second order neurons?
main sensory nucleus and spinal trigeminal nucleus
what does the main sensory nucleus do and where is it located?
in the mid pons
mediates fine touch, two point discrimination, joint position, vibration, and sends fibers to thalamus
what does the spinal trigeminal nucleus do?
axons cross the midline and ascend in trigeminophthalmic tract (TTT) to the ventral posteromedial (VPM) nucleus in the thalamus
where are the third order neurons for CN5?
in thalamus - they ascend carrying sensory signals to primary sensory cortex
what is neuralgia?
intense lancinating pain (cutting, piercing, burning), shooting along the nerve and is paroxysmal (sudden or brief)
cause is unknown or due to nerve irritation or damage
what are the 3 primary facial neuralgias (non-headache)?
trigeminal neuralgia, Raeder’s paratrigeminal syndrome and post-herpatic neuralgia (PHN)
how is trigeminal neuralgia diagnosed?
usually by the patient history
who typically gets trigeminal neuralgia?
onset > 50, females slightly more than males and may have a familial predilection
what are the key features of trigeminal neuralgia?
paroxysmal pain is excruciating (seconds long), triggered by hypersensitivity, hemifacial (V2 most common, V1 least common) and without significant sensory loss
what is the etiology for trigeminal neuralgia?
compression, irritation, inflammation, peripheral CN5 injury, demyelination zone (MS)
often cause is unknown
what is the prognosis for trigeminal neuralgia?
tends to get worse over time, temporary spontaneous remission is possible but never permanent and medical management eventually fails (25-50%)
what is the first line of treatment for trigeminal neuralgia?
medical = Carbamazepine (tegretol) is the most effective
phenytoin is less effective
what surgery for trigeminal neuralgia is typically used in younger patients?
microvascular decompression (craniotomy) = isolate nerve from adjacent vessel with a sponge long term pain relief and lowest recurrence most cost effective
which treatment for trigeminal neuralgia has a delayed response?
the non-invasive stereotactic radiosurgery with a gamma knife = ionizing radiation targets CN5 roots
delayed 2-6 months
recurrence is common
what treatment for trigeminal neuralgia is used for patients with MS, elderly and pain persisting after MVD?
percutaneous transovale procedure = needle through foramen ovale to target V3
what is raeder’s paratrigeminal syndrome?
severe unilateral ocular (V1) pain, ipsilateral oculosympathetic palsy or partial horner’s (no anhydrosis) and associated with tearing, erythema and decreased IOP
what type of pain does a patient with raeder’s paratrigeminal syndrome have?
single episode hours - weeks, pain exacerbates with touch, self-limiting within 2-3 months and occasionally recurrent
