From Top Down to Bottoms Up In Fibromyalgia
For the past decade or so research evidence has suggested that fibromyalgia is more a brain disorder than a body disorder. Studies indicating increased substance P levels, increased activity in the pain sensing and decreased activity of the pain inhibitory sections of the central nervous system suggest people with FM have a nervous system primed to produce pain. This is the central sensitization theory suggesting FM is literally a ‘top-down’ disorder that starts in messed up circuits in the brain and goes down from there.
Recent studies taking a close look at the muscles and skin, particularly the stunning small fiber neuropathy findings, suggest it’s far too early to dismiss the body in FM. In fact, some researchers are suggesting that the ‘central sensitization’ present may be driven by problems in the body – a stunning turnaround from a decade or so when the body was more less, excluded from the conversation.
This may not be just about fibromyalgia. A major fibromyalgia theory touches so closely on findings in both chronic fatigue syndrome and fibromyalgia that it’s hard to see how it doesn’t apply to both. In fact, if this theory is right the pain and fatigue in ME/CFS and FM my very well come down to two common denominators in both diseases; the sympathetic nervous system and the blood.
Let’s just back up and look at some recent things we’ve learned regarding the SNS/blood interaction.
- Allodynia may be caused by an inflammatory cascade (ischemia) produced by low blood flows to the tissues.
- Low blood flows to the muscles are present in both fibromyalgia and chronic fatigue syndrome.
- ME/CFS patients have such reduced aerobic functioning capacity that very early in exercise they enter into an anaerobic energy production state that spews out toxic metabolites that cause pain and inflammation.
- Recent studies have highlighted the role inflammation and inflammatory cytokines play in fibromyalgia.
- Low blood volume is present in FM as well as ME/CFS.
Now a theory posits that those anaerobic metabolites and inflammatory cytokines caused by low blood flows are driving the central nervous system sensitization present in ME/CFS/FM. This theory suggests that an overactive sympathetic nervous system that constricts the small blood vessels in the body is the cause.
In this study researchers looked for evidence of sympathetic nervous system/blood vessel problems in one of the most blood and blood vessel rich areas of the body – the hands.
- Pain Med. 2013 May 20. doi: 10.1111/pme.12139. Excessive Peptidergic Sensory Innervation of Cutaneous Arteriole-Venule Shunts (AVS) in the Palmar Glabrous Skin of Fibromyalgia Patients: Implications for Widespread Deep Tissue Pain and Fatigue. Albrecht PJ, Hou Q, Argoff CE, Storey JR, Wymer JP, Rice FL.
Small Caliber Nerves – Big Caliber Effects?
Our hands are more than just tools. It turns out that sensory and autonomic nervous system nerve fibers permeate the small blood vessels in our skin. These small ‘caliber’ blood vessels help us adjust to temperature changes and provide sensory information. They dilate, bringing blood to our surface, when get too high and enable us to retain heat by constricting when we get cold. These researcher biopsied small pieces of skin in the hands to see what was going on at this site of intense nervous/cardiovascular activity in our body. If the sympathetic nervous system was messed up it should definitely show up here…and it did.
Taken together, these data indicate that FM patients have a neurovascular pathology in the palms of the hands predominantly increasing the peptidergic sensory innervation of the AVS.
Sensory nerves that relayed pain and sensory signal and dilated the blood vessels abundance (feeling too much pain?) were highly abundant in the small shunts between the arteries and veins in the hands of the FM patients. So what you might say? Look at how blood filled your hands are.
Loaded with small capillaries, the hands of humans are not only important thermoregulatory’ devices but they’re almost important reservoirs of blood. It turns out that the blood flow to the hands far exceeds their metabolic demands; the hands are effectively blood storage sites that allow the blood to gets quickly shunted to areas in need. Studies indicate that as soon as you start to exercise blood flows out of your hands and into your muscles.
In fact your hand can withstand great blood loss without damage as well; they’re simply very well adapted to moving the blood around…
Of course, there’s also the pain issue. High levels of sensory nerves suggest high levels of pain as well.
The authors of the study said
“the excess sensory innervation may itself explain why fibromyalgia patients typically have especially tender and painful hands.
“But, in addition, since the sensory fibers are responsible for opening the shunts, they would become particularly active under cold conditions, which are generally very bothersome to fibromyalgia patients.“
Blood In…..Not Blood Out
Except may not in fibromyalgia and maybe not chronic fatigue syndrome. These researchers found evidence that shunts between the arterioles and veins in the hands were high innervated with blood vessel dilating nerves.
That suggested blood easily found its way into the hands but not out of them and that may be a problem if you want to exercise, think hard or sleep. The authors suggested that the fatigue during exercise, the cognitive problems during thinking and the problems sleeping could all be a function of all these dilated small blood vessels in FM patients hands. They believe that those low blood flows in the muscles that cause so much pain after exercise could start right there in your overly blood-rich hands.
Instead of this study finding evidence of excessive SNS activation, it found a reason for that increased SNS activation elsewhere. With the blood stuck in the hands, the SNS is, no doubt, tightening blood vessels down elsewhere in an effort to squeeze it out to the muscle and brain.
“Instead of being in the brain, the pathology consists of excessive sensory nerve fibers around specialized blood vessel structures located in the palms of the hands,” said Dr. Frank Rice, president of Intidyn and the senior researcher on the study.
Interestingly, given the gender imbalance in this disease, estrogen is a huge player in sensory nerve production in the hands and females typically, have twice the sensory innervation in their hands than men. It seems a bit much to say it’s all in the hands but throw in problems with blood volume, dilated arteries elsewhere and issues with the mitochondrial uptake of oxygen, etc. with shunts that appear to be chronically open in one of the most blood-rich areas of the body, and maybe you really have something.
Perhaps the blood really will out in ME/CFS and fibromyalgia.
The authors are examining male FM patients to see if the same pattern applies.
New Treatments Possibly on Tap
They noted that SNRI drugs that act on the brain also act on the nerve endings in the skin and may be helpful in FM and the author of the study suggests the finding opens the door for new therapeutics.
“This discovery provides concrete evidence of a fibromyalgia-specific pathology which can now be used for diagnosing the disease, and as a novel starting point for developing more effective therapeutics.”
Senior Research Chair of the Alan Edwards Center for Pain Research at McGill University, Dr. Gary Bennett felt so, as well, stating
“It is exciting that something has finally been found. We can hope that this new finding will lead to new treatments for fibromyalgia patients who now receive little or no relief from any medicine.”
- Check out an excellent reader-friendly explanation of all this by the authors of the study.
- Coming up soon: bottoms up indeed for FM; the stunning small nerve fiber neuropathy findings suggest fibromyalgia should perhaps be called fibroneuralgia….