zap wrote:If the valves in the right JV were missing or compromised (but not blocked), would MRV even show it? I'm wondering if an apparently normal MRV could result when a patient with missing jugular valves is scanned ...
So even in the absence of CCSVI, could transient blood reflux up into the brain cause MS lesions and damage, if valves are not normal?
And here's a sort of out-there question I've harbored for awhile now - could sneezing cause such backjets? I sneeze VIOLENTLY, several times, on most days, and I've often wondered if the spike in thoracic pressure this causes could be an issue ...
In case that sounds wacky, check out these:
Internal jugular valves are the only venous valves between the heart and the brain. Conditions such as coughing and other precipitating activities may result in retrograde cerebral venous flow because of the absence or presence of internal jugular valve incompetence, allowing brief transmission of high venous pressure and resulting in brain disturbance.
The pathophysiology of primary exertional headache (EH) is unknown. Physical exertion is associated with Valsalva-like manoeuvres (VM). VM leads to increased intrathoracic pressure and reduces cerebral venous drainage. Internal jugular vein valve incompetence (IJVVI) leads to retrograde venous flow during VM with transient increase of intracranial pressure
http://www3.interscience.wiley.com/jour ... 6/abstract
I know that this issue has been discussed before, regarding Transient Global Amnesia - and been sort of dismissed, since "CCSVI is chronic" and the TGA patients' "valsalva-like" spikes aren't chronic, they are transient damage ... but I think there is plenty of grey area between, and Schelling's work seems to support this.
Repeated minor spikes over time is chronic - who says the reflux must be constant and unwavering to cause MS like lesions and symptoms?
There is also a continuum of thoracic pressures - for example, perhaps poor sitting posture, sleeping position, etc and/or unusual physiology causes an increased thoracic pressure in the absence of venous stenoses. This would not show up in MRV (apparently valve incompetence requires special doppler tests), but could still result in CCSVI - perhaps more mild than those with seriously blocked jugulars, but serious nonetheless!
http://www.thisisms.com/ftopic-9863-day ... ar-15.html