rblog

The results from the latest MRIs (Brain, Cervical Spine) are in - and everything looks fine. Which caused the radiologists to review the previous MRI (Lumbar, Thoracic) - and it appears that they have found something amiss. There is something in the Thoracic MRI that appears to indicate a Arteriovenous Fistula. This is a misconfiguration of the blood vessels, whereby the arteries that should route blood through smaller and smaller capilleries (for transport to cells) get tangled and route the blood directly into the veins for transport back to the heart. This reduces/eliminates blood flow to certain cells, which just isn't good. A very brief description is available here.

The first topic - how is this related to my nervous system symptoms. AV Fistulas (or in general, AV Malformations or AVMS) can occur anywhere in the body, with varying severity. Mine would be along the spinal cord and is sometimes called a neurological AVM, affecting about 0.1 % of Americans (300,000). Most people don't even know they have an AVM as the symptoms can be ignored (but since there is a 1/100 chance the AVM will kill you, ignoring it is a bad idea).

Symptoms appear due to a slow build up of neurological damage. As described above, the basic mechanism for damage is cell detioration and death due to lack of oxygen. In particular, the arteries in the area become swollen (as they dump blood directly into the veins and do so at higher volumes than the blood could flow into small capillaries). The veins that drain blood away from the capillaries (the ones no longer receiving blood) become constricted - which is the condition of stenosis. The walls of both arteries and veins weaken - leaving susceptibility to aneurysms.

How serious is an AVM? The best way to think of this is as a possible stroke of the spinal cord. Not very likely to happen but it if does, a bit on the nasty side. If the bleeding stays small, all is good - but it could increase at any point in time and start a significant hemorrage.

Our next step is to determine whether this is really an AVM or not. At this point, we have an observed abnormality in the flow of nerve impulses through the spinal cord. That is likely to be related to the irregularity seen in the thoracic MRI. That irregularity could well be the AVM. We will be using a recently developed flavor of MRI called the magnetic resonance angiography (MRA), which will measure the pattern and speed of blood flow and spinal fluid. But hey, on the positive side, it means no lumbar puncture for now. Although I don't really relish the thought of spending a long time in an MRI machine.

And of course, what are the treatment options? Since we don't know that it is an AVM, I won't spend much time on this, but hey, at least there are some options! They boil down to:
a) Surgery - cut it out - invasive, but gets it all (and who wants spinal cord surgery - ug)
b) Endovascular embolization - seal it off - insert catheter, shoot some glue into the connection between the artery and the vein, forcing the flow back into the capillaries.
c) Radiosurgery - burn it out - highly focused radiation damages the blood vessels creating the unwanted connection.

More details available here, which is the one site I read for this summary - I will read some other sites, especially concerning the MRA and post back anything I find interesting.