Eight months ago, I asked the question: Did chiropractic manipulation of her neck cause Katie May’s stroke? Now, it appears, I know the answer, and the answer is yes:

Katie May, a model who posed for Playboy and gained a massive following on Snapchat, suffered a “catastrophic” stroke in early February and later died after being taken off life-support. Now, TMZ reports reports that a visit to the chiropractor left her with an injury that precipitated the stroke. TMZ obtained May’s death certificate, which says that she suffered a blunt force injury during a “neck manipulation by [a] chiropractor.” That injury tore an artery in her neck and cut off blood flow to her brain, which led to the stroke that killed her.

Several of you e-mailed me news reports of the coroner’s finding (as well as other stories referencing the TMZ story). To be honest, I had forgotten about this story, not having heard anything about it since I blogged about it in February, and I was surprised at how this update came seemingly out of the blue. I would have loved to see the actual autopsy report, rather than a snippet of it quoted by TMZ and other magazines, but I take what I can get.

Before this story, I have to admit that I didn’t know who Katie May was, but I did learn that she was known as the “Queen of Snapchat,” for her posting of photos of herself in which she was scantily clad. Indeed, between Instagram and Snapchat, she had quite the social media empire going. At the time of her death, she was only 34 years old and left behind a seven year old daughter. It was a horrible, tragic tale. May was young and building a business, and her death was completely unnecessary, making it even more depressing to contemplate.

Here’s what happened. Late last January, May was doing a photo shoot. It’s unclear exactly how it happened, but somehow it did happen. May fell—hard—and hit her neck or head on something. Afterward, she complained of neck pain that was intense enough that she apparently went to the emergency room to be checked out. Actually, stories differ here, with what her family said, namely that she never sought medical care. Be that as it may, we do know that May went to a chiropractor for a neck adjustment, as she Tweeted soon afterward:

Pinched a nerve in my neck on a Photoshoot and got adjusted this morning. It really hurts! Any home remedy suggestions loves? XOXO — Katie May (@Ms_katiemay) January 29, 2016

Two days later, May responded to a fan who asked how her neck was feeling:

Thanks love! It still hurts, going back to chiropractor tomorrow xoxoxo https://t.co/xTw080sjrK — Katie May (@Ms_katiemay) February 1, 2016

So May went to her chiropractor on February 1. That evening, she collapsed and was rushed to the hospital. It was a Monday. By Thursday evening, she was removed from life support, and died a few hours later.

If you read my previous post on the Katie May, you might remember that I spent a lot of verbiage in my own inimitable fashion going over a couple of questions. First, was it a stroke from chiropractic manipulation that killed Katie May? Second, what is the evidence base covering chiropractic manipulation and stroke? As part of the second discussion, I pointed out that, while the evidence base supporting chiropractic manipulation as a cause of strokes due to occlusion of the vertebral or basilar arteries is pretty convincing, the evidence that chiropractic manipulation can cause carotid artery injury is much less convincing.

It’s also less plausible, too, given that there is a clear physical mechanism for injury to the vertebral arteries. To help you see why, I thought it would be worthwhile to post this picture again, laying out the anatomy of the vertebrobasilar system. Basically, two very important arteries that supply blood to the brain pass through the two highest vertebrae, the atlas (C1, so named because it was thought to support the head the way the mythical Atlas held up the earth) and the axis (C2). Importantly for understanding how chiropractic could cause vertebrobasilar strokes, the vertebral arteries are tethered to the spine and make a big loop around the atlas before entering the skull and merging to form the basilar artery (click to embiggen):

Vertebral artery anatomy. The arrows point to the vertebral artery. Note how it bends around bony protrusions.

It’s not difficult to see how a rapid rotation of the head could potentially stretch the basilar arteries. Generally, chiropractors describe this as “high velocity, low amplitude” (HVLA), which it is, but, given the constraints of vertebral artery anatomy, high amplitude is not required to cause injury. With HVLA, it is quite possible to tear the intima (the lining of the artery consisting of vascular endothelial cells). Intimal tears become “sticky” for platelets, leading them to lodge there and start to form a clot. This is the same reason atherosclerotic plaques can lead to strokes when they are in the carotid artery and can cause myocardial infarctions (death of heart muscle; a.k.a., a heart attack) when in the coronary arteries. The “rough” area of the plaque is thrombogenic; i.e., has a tendency to attract platelets and cause clots. When a clot forms in such an injured area of intima, regardless of where the artery is, one of three things can happen. It can resolve completely, which is what usually happens; it can resolve but leave a narrowed segment of the artery as it resolves; or it can break off and flow further downstream, there to lodge where the artery narrows and block blood flow. When that happens in the brain, it’s called a stroke.

Now, take a look at chiropractic neck manipulation:

And here’s another example:

And still more:

You get the idea. If you cringe when you hear the pop during the violent twist given to the neck, you’re not alone. So do I. It is that “high velocity, low amplitude” (HVLA) twist that can injure the intima of the artery, setting up the condition for a stroke. What surprises me is that the risk isn’t much higher than what studies show. The human body is more resilient than one would imagine, and, absent pre-existing atherosclerotic disease, the risk remains low. On the other hand, given that there is no benefit from HVLA chiropractic neck manipulation, the risk-benefit ratio is basically infinity, because the potential benefit is zero. Also, the risk might be small, but, as Katie May shows us, the the consequences of that risk can be catastrophic.

Another aspect I discussed was whether Katie May’s stroke could have been due to the trauma she suffered at her photo shoot a day or two before her first chiropractic manipulation. Now that we know, assuming that TMZ is accurately relaying the results of the coroner’s report, that May had a tear in her left vertebral artery, it’s almost certain that the chiropractor accidentally killed her through neck manipulation. That is what the coroner concluded, that this injury to her vertebral artery occurred during chiropractic neck manipulation.

In the end, there is no longer any reasonable doubt. Katie May’s death was unnecessary and due to her subjecting herself to the quackery that is chiropractic.