Too Many Nerves: New Pathology Discovered in Fibromyalgia
By Adrienne Dellwo, About.com GuideJuly 2, 2013
Researchers say that people with fibromyalgia may have a lot of extra sensory nerves to a particular part of the circulatory system, which could cause severe pain and tenderness, dysregulate blood flow, and make it hard for the body to regulate its internal temperature.
Arteriole-Venule Shunts & Why They're Important
Here's a quick anatomy lesson to help you understand this finding. In your circulatory system, you have several types of blood vessels, and the two types we're looking at for this study are called arterioles and venules. Think of plumming for a moment - arterioles and venules are different sizes of pipes, and they need valves to connect them. Those valves are called arteriole-venule shunts (AVS.)
AVS control whether your blood stays in the larger vessels or flows into smaller ones called capillaries. This is how your body controls heat, which is moved around your body by blood. The AVS are opened and closed by specialized nerves, which sense blood flow along with pain and temperature.
In this study, scientists discovered that participants with fibromyalgia had a bunch of extra nerves running to the AVS. More nerves means more sensory input - i.e., an extreme reaction to sensations such as pain and heat.
What Does it Mean?
In this study, researchers looked at the nerves and blood vessels in the hand. We still don't know if these extra nerves are all over our bodies, but if they are, it helps explain why we hurt everywhere. It could also explain why our internal thermostats are all over the place. (For a clarification on this point, see the comment below from Dr. Frank Rice, senior researcher on this study.)
On top of that is blood-flow issues. Blood carries oxygen and nutrients to the muscles, but if the body has trouble re-directing blood flow in response to exertion, the muscles become deprived, and therefore weak. Lactic acid builds up and causes that burning sensation we're all too familiar with.
Additionally, you know that painful pins-and-needles sensation you get when a foot or hand falls asleep? It's caused by inadequate blood flow, called ischemia, and some doctors have long believed that ischemia is responsible for some fibromyalgia pain.
The researchers behind this study also say this finding is a clear pathology that could lead to diagnostics tests as well as future treatments. All that seems promising, but then so do a lot of other studies. Time will tell.
Here's something to keep in mind about this study: it was funded by two companies that produce fibromyalgia medications - Cymbalta (duloxetine) and Savella (milnacipran.) A press release on the findings mentions that the excess nerves could be why those two drugs work for us, which makes me skeptical about new therapies. Drug companies aren't in the habit of pursuing new drugs when they can boost sales of the ones already on the market.
Also, this was a small study with just 24 women. We need a lot more research before we can say, without a doubt, that this is what's going on in our bodies.
Still, this is an interesting theory that I think deserves ongoing study. I hope other researchers will pick up on this as well, to reduce concerns about bias.
This study was a progression of one published back in 2009. Read more:Fibromyalgia & a Newly Discovered Sensory System.. (Please click on that phrase, it leads to another newly discovered cause of Fibro.)
Also read Serotonin & Blood Flow for an alternate theory of why we have blood-flow problems.