Compressive vascular disorder

General

CN3, 4, 6

Abnormal movements of the motor ocular CNs (third, fourth and sixth) are most often in relation with causes others than NVC.
Hyperactive syndromes of the motor CNs others than the facial nerve are infrequent.

CN 5: Trigeminal neuralgia

Muscular spasms attributed to the masticatory motor root of the Vth CN have been only sporadically reported.
Most common

CN 7: Hemifacial spasm

Nervus intermedius neuralgia
2nd most common

CN 9: Glossopharyngeal neuralgia

3rd most common

CN 8: Vestibular paroxysmia

CN9/10

Vascular compression of the ventrolateral medulla, ventrally to the ninth to tenth CN REZ, has been hypothesized as a possible cause of neurogenic essential blood hypertension.

CN 11:

Spasmodic torticollis,

Hypothesized by some to be due to NVC of the 11th CN should rather be classified within the frame of dystonias/ dyskinesias.
Origin is likely brainstem/ basal ganglia dysfunction rather than CN 11 compression.

CN12

Only one publication has reported on hemi- lingual spasm by NVC on the twelfth root.

A few cases several CNs in the same individual can be affected by hyperactive dysfunction.

MVC pathophysiology

Mechanism

Artery in contact with nerve → Chronic pulsatile compression of the root → demyelination of the nerve → Demyelinated zones act as neosynapses → formation of ephaptic transmission (short circuit )

Explains the triggered and irradiating clinical manifestations.
Operative microscope frequently showed a groove with a greyish aspect marked by the compressive vessel, namely a pulsatile artery, or also and not rarely a (non- pulsatile) vein testifying of a focal demyelination.
Root entry zone (REZ)

Classically the NVC are preferentially situated at the REZ
No ‘official’ definition of the REZ.

Generally accepted that REZ corresponds to the portion of the root from brainstem to the transitional zone (TZ)/Obersteiner-redlich zone:

Junction between the portion of the root with myelin of central type and the portion of the root with myelin from Schwann origin

More ‘excitable structures

Central portion
TZ

Locally generated ectopic influxes → retrograde firing of the corresponding CN nucleus (i.e. through a ‘kindling- like’ phenomenon), → hyperexcitability and hyperactivity of the nucleus cells.

This hyperactivity generated in the central nervous system is consistent with the epileptic- like clinical manifestations of many of these CN hyperactive syndromes, as well as of their particular responsiveness to anticonvulsants.

(A) Photomicrographs of longitudinal sections stained with Luxol fast blue, of trigeminal, facial, vestibulocochlear, glossopharyngeal, and vagus roots, at same scale for comparison. The transitional zone (TZ) between central myelin portion and myelin of Schwann portion is underlined.

(B) Comparative drawings of central myelin portions, obtained from mean values of the length (with diameter), of the corresponding roots.

Painful lesions of the cranial nerves and other facial pain

Pain attributed to a lesion or disease of the trigeminal nerve

Trigeminal neuralgia

Classical trigeminal neuralgia

Trigeminal neuralgia developing without apparent cause other than neurovascular compression.
Classical trigeminal neuralgia, purely paroxysmal (Typical TGN)

Classical trigeminal neuralgia without persistent background facial pain.

Classical trigeminal neuralgia with concomitant continuous pain (Atypical TGN)

Classical trigeminal neuralgia with persistent background facial pain.

Secondary trigeminal neuralgia

Trigeminal neuralgia caused by an underlying disease
Trigeminal neuralgia attributed to multiple sclerosis

TGN criteria +
Multiple sclerosis (MS) has been diagnosed +
An MS plaque at the trigeminal root entry zone or in the pons affecting the intrapontine primary afferents has been demonstrated by MRI, or its presence is suggested by routine electrophysiological studies1 showing impairment of the trigeminal pathways

Trigeminal neuralgia attributed to space-occupying lesion

TGN criteria +
A space-occupying lesion in contact with the affected trigeminal nerve has been demonstrated +
Pain has developed after identification of the lesion, or led to its discovery

Trigeminal neuralgia attributed to other cause

TGN criteria +
A disorder other than those described above, but known to be able to cause trigeminal neuralgia, has been diagnosed
Pain has developed after onset of the disorder, or led to its discovery

Idiopathic trigeminal neuralgia

Trigeminal neuralgia with neither electrophysiological tests nor MRI showing significant abnormalities.
Idiopathic trigeminal neuralgia, purely paroxysmal
Idiopathic trigeminal neuralgia with concomitant continuous pain

Painful trigeminal neuropathy

Facial pain in the distribution(s) of one or more branches of the trigeminal nerve caused by another disorder and indicative of neural damage.

How to diff from trigeminal neuralgia

The primary pain is usually continuous or near-continuous, and commonly described as burning or squeezing or likened to pins and needles.
Superimposed brief pain paroxysms may occur, but these are not the predominant pain type.

There are clinically detectable sensory deficits within the trigeminal distribution, and mechanical allodynia and cold hyperalgesia are common, fulfilling IASP criteria for neuropathic pain.

As a rule, allodynic areas are much larger than the punctate trigger zones present in trigeminal neuralgia.

Painful trigeminal neuropathy attributed to herpes zoster

Trigeminal post-herpetic neuralgia

Painful post-traumatic trigeminal neuropathy

(A) Facial and/or oral pain in the distribution(s) of one or both trigeminal nerve(s) and fulfilling criterion C

(B) History of an identifiable traumatic event1 to the trigeminal nerve(s), with clinically evident positive (hyperalgesia, allodynia) and/or negative (hypaesthesia, hypalgesia) signs of trigeminal nerve dysfunction

Pain is localized to the distribution(s) of the trigeminal nerve(s) affected by the traumatic event

Pain has developed <6 months after the traumatic event

(D) Not better accounted for by another ICHD-3 diagnosis.

Painful trigeminal neuropathy attributed to other disorder

Idiopathic painful trigeminal neuropathy

Pain attributed to a lesion or disease of the glossopharyngeal nerve

Glossopharyngeal neuralgia

(A) Recurring paroxysmal attacks of unilateral pain in the distribution of the glossopharyngeal nerve and fulfilling criterion B

Ear, base of the tongue, tonsillar fossa and/or beneath the angle of the jaw

(B) Pain has all of the following characteristics:

Lasting from a few seconds to 2 minutes

Severe intensity

Electric shock-like, shooting, stabbing or sharp in quality

Precipitated by swallowing, coughing, talking or yawning

Classical glossopharyngeal neuralgia

Glossopharyngeal neuralgia developing without apparent cause other than neurovascular compression.

Secondary glossopharyngeal neuralgia

Glossopharyngeal neuralgia caused by an underlying disease.

Idiopathic glossopharyngeal neuralgia

Glossopharyngeal neuralgia with no evidence either of neurovascular compression or of causative underlying disease.

Painful glossopharyngeal neuropathy

In the location of the Glossopharyngeal nerve

Ear, base of the tongue, tonsillar fossa and/or beneath the angle of the jaw

The primary pain is usually continuous or near-continuous, and commonly described as burning or squeezing or likened to pins and needles. Brief paroxysms may be superimposed, but they are not the predominant pain type.

Painful glossopharyngeal neuropathy attributed to a known cause

Idiopathic painful glossopharyngeal neuropathy

Pain attributed to a lesion or disease of nervus intermedius

Nervus intermedius neuralgia

(A) Paroxysmal attacks of unilateral pain in the distribution of nervus intermedius and fulfilling criterion B

Auditory canal, auricle, in the region of the mastoid process and occasionally the soft palate, and may sometimes radiate to the temporal region or the angle of the mandible.

(B) Pain has all of the following characteristics:

Lasting from a few seconds to minutes

Severe in intensity

Shooting, stabbing or sharp in quality

Precipitated by stimulation of a trigger area in the posterior wall of the auditory canal and/or periauricular region

Classical nervus intermedius neuralgia

Nervus intermedius neuralgia developing without apparent cause other than neurovascular compression.

Secondary nervus intermedius neuralgia

Idiopathic nervus intermedius neuralgia

Painful nervus intermedius neuropathy

Pain in the nervus intermedius area but this is more constant (might have periods of greater and lesser intensity)

Painful nervus intermedius neuropathy attributed to herpes zoster

Post-herpetic neuralgia of nervus intermedius

Painful nervus intermedius neuropathy attributed to other disorder

Idiopathic painful nervus intermedius neuropathy

Occipital neuralgia

(A) Unilateral or bilateral pain in the distribution(s) of the greater, lesser and/or third occipital nerves and fulfilling criteria B-D

(B) Pain has at least two of the following three characteristics:

Recurring in paroxysmal attacks lasting from a few seconds to minutes

Severe in intensity

Shooting, stabbing or sharp in quality

Dysaesthesia and/or allodynia apparent during innocuous stimulation of the scalp and/or hair

Either or both of the following:

Tenderness over the affected nerve branches
Trigger points at the emergence of the greater occipital nerve or in the distribution of C2

(D) Pain is eased temporarily by local anaesthetic block of the affected nerve(s)

(E) Not better accounted for by another ICHD-3 diagnosis.

13.5 Neck-tongue syndrome

13.6 Painful optic neuritis

13.7 Headache attributed to ischaemic ocular motor nerve palsy

Tolosa-Hunt syndrome

13.9 Paratrigeminal oculosympathetic (Raeder’s) syndrome

13.10 Recurrent painful ophthalmoplegic neuropathy

13.11 Burning mouth syndrome (BMS)

13.12 Persistent idiopathic facial pain (PIFP)

13.13 Central neuropathic pain

13.13.1 Central neuropathic pain attributed to multiple sclerosis (MS)
13.13.2 Central post-stroke pain (CPSP)