When a stroke is not a stroke: Sen. Tim Johnson, (D-SD)

This post will probably have a very limited shelf-life, but my speculative interpretation of the confusion surrounding the Senator is 1.) he had a transient ischemic attack, or TIA, 2.) as part of the work-up he had carotid duplex imaging that demonstrated narrowing of his carotid artery, 3.) he underwent a carotid endarterectomy, and will be fine.

So when his spokesperson states that "he had suffered neither a stroke nor a heart-attack she is correct, as a TIA is not a stroke. It is just a temporary and reversible deprivation of oxygen-carrying blood to a region of the brain. However, it can be a prelude to a stroke, and atherosclerosis of the carotids can further put you at risk. High-grade narrowing calls for surgery.

In all likelihood he will resume his duties within a week or so. I'm sure all of this will come out before the end of the week. My left-leaning reader(s) can breathe easy.

UPDATE: Now it's being called brain surgery, which would imply he had an aneurysm clipping. "Critical condition" is not a strictly medical term, it could just mean he is in the neurosurgical intensive care unit following surgery, which is pretty routine. His spokesperson had said earlier they "got it early" so I doubt he had a subarachnoid hemorrhage (which more likely present with intense headache rather than aphasia).

UPDATE 2 (20:18 EST 12.14.06): Okay, so it was an AVM. These are a tangle of direct vascular connections between arteries and veins, resembling bloody bloated spiders. Some of them can get quite large. Most bleed very slowly. My money is still on Sen. Johnson resuming his duties this spring.