You are going to see it referred to by many names: Cerebral Venous Thrombosis (CVT), Venous Sinus Thrombosis (VST), Cavernous Sinus Venous Thrombosis (CSVT)--all a little bit different but within a spectrum of disease we will talk about today. This is a rare cause of headache, but if you do not have a disease script for this diagnosis, you will miss it! Without the right treatment the patient will get much worse, but if you do think about it and diagnose it, these patients can do very well.

To talk about CVT, I have brought on new EMCrit Team Member, Casey Albin.
Casey Albin MD
I first discovered Casey on Twitter where she does insanely good neuro-critical care tweetoriols. She is an Assistant Professor of Neurology and Neurosurgery in the Division of Neurocritical Care at Emory University School of Medicine.

 
Casey Wrote Up Her Own Shownotes (b/c she is Amazing!)
When should I think about Venous Sinus Thrombus?

* Understanding the presenting signs requires knowing a little bit about the pathophysiology
* Remember that the anatomy of the brain is quite different in that the arteries and veins do not run in parallel proximity or supply and drain the same territories.
* When we talk about Cerebral Venous Thrombosis we are talking about to subtypes that often coexist

* Cerebral Vein Thrombosis
* Venous Sinus Thrombosis

* Often the patient has both and colloquially these get interchanged to mean the same thing, but

* Cerebral veins drain the brain parenchymal and there are two systems – superficial and deep
* These are draining the brain parenchyma and are beneath the meninges

* These ultimately drain to venous sinuses which are venous channels that are between the layers of dura.

* The most important of these are the sagittal sinus, transverse sinuses, straight sinus and cavernous sinus.

The reason the distinction matters is the downstream consequence of a vein being occluded is going to be a little different than if a sinus is occluded.

* When a vein is occluded you get a downstream blockage to flow within the parenchymal (remember, that’s where the vein are!)
* this causes a build=up of pressure which leads vasogenic edema
* If the pressure is great enough that you don’t get forward flow à cytotoxic edema and cell death, a so-called “Venous Infarct”
* And if there is still pressure into the dying tissue you can get an intraparenchymal hemorrhage

This can also occur when a Sinus is occluded, but it may not, but if enough of the venous sinuses are occluded you can see a dramatic rise in intracranial pressure.  Because not only are you impeding VENOUS drainage but also CSF is ultimately reabsorbed back into the sinuses through the arachnoid granulations.

So, the reason all of the pathophysiology matters is that the patient can have different symptoms depending on what is physiologically happening.

That’s what makes diagnosing this so tricky, because in many ways VST is a mimicker of other pathology and it’s a very rare etiology stroke (<1%)

There is a really broad spectrum of the way this can present.

* International Study on Cerebral Vein and Dural Sinus Thrombosis group found that almost 90% of patients had a headache and about a 1/3 had papilledema
* Headache was most commonly subacute and crescendo type, not sudden onset WHOL although that may happen especially with associated IPH
* Localizing signs like paresis, aphasia,