Trigeminal Neuralgia

[Evan B. Stubbs]

Marian Russell (MRussell at sgit.iaea.or.at) wrote:
: tommy bergenheim <tommy.bergenheim at neuro.umu.se> wrote:

: >Trigeminal neuralgia in its primary form is essentially considered
: >to be caused by vascular compression of the nerve root adjacent
: >to the pons.

: Why is it that the periods of pain are intermittent and that there can
: be long periods of remission?  If it is caused by vascular compression,
: why is the pain not constantly there?

: >The facial pain syndrome sometimes appearing after 
: >herpetic infections presents with quite different symptoms. Further on, 
: >the postherpetic pain does not respond to the treatment modalities,
: >i.e. microvascular decompressiuon, radiofrequency lesioning or glycerol
: >rhizotomy, used for trigeminal neuralgia.

: I was not asking about postherpetic pain, but rather asking if it is
: possible that TN could be caused by an internal herpes simplex infection.
: Since the HSV which appears as cold sores on the lips lies dormant in the 
: trigeminal ganglion between attacks, why couldn't it attack the 
: trigeminal nerve itself?  Could TN be cause by an internal herpes 
: infection?  Is there even such a thing as an internal herpes infection?

: Marian Russell
: MRussell at sgit.iaea.or.at

I'm not an expert in neurology, but I can offer some information. 
According to The Mosby Medical Encyclopedia, revised edition: 
...complications of Herpes Zoster, an infection caused by varicellazoster 
virus which affects mainly adults, include geniculate zoster with 
involvement of the ear, face, and soft palate. Ophthalamic herpes zoster 
is another complication which can result in corneal damage in the eye. 
One of the symptoms of zoster infection is neuralgia, a jabbing pain. It 
is well known that the herpes zoster virus can lay dormant in sensory 
nerve roots following a main infection (chicken pox). Usually after age 
50, the virus is "reactivated" with eruptions following the path of a 
nerve on the trunk, face, or limbs. As outlined in Principles of 
Neurology, 5th ed.: Trigeminal neuralgia characterized by persistent 
peroxysms of stabbing pain have a vascular, neoplastic, degenerative 
(MS), or unknown etiology. It is of interest to note that postzoster 
neuralgia is also characterized by similar symptoms. However, this type 
of facial pain is usually associated with ophthalamic division of the 5th 
nerve rather than the second and third divisions of the trigeminal nerve. 
It is difficult to explain why some sensory nerves serve as hosts for the 
zoster virus while others are apparently resistant. Any 
"neurovirologists" out there know why this might occur?

Evan Stubbs, Ph.D.
Research Health Scientist
Assistant Professor
Hines VA/Loyola University Medical Center