Fibromyalgia and the Brain

By Karen Crosby

This month I wanted to cover the brain involvement in a little more detail.  I will start by looking at how the brain has been a major player in the symptoms of the condition (and other chronic pain conditions too).

Stress Systems and how this affects pain

Stress has been a major player in the development of fibromyalgia, alongside how we cope with stress, genetic makeup and gender.

It is unclear however which physiological process brings together the relationship between stress and fibro.

HPA Axis

The hypothalamic-pituitary-adrenal axis (HPA Axis) is a term used describing the interaction between the pituitary gland, the hypothalamus and the adrenal glands.  This is the creation of the body’s response to stress, and results in the production of the stress chemical cortisol.

Autonomic Nervous System

The autonomic nervous system is directly involved in our physical response to stressful situations. This is divided into the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). 

When the body is stressed the SNS produces what is known as the “fight or flight” response.  It is how we evolved to remove ourselves from danger.  Simply put, it is standing and fighting or running away from the danger, and it has helped us survive as a species.

After our perceived danger has passed, the PNS calms the body down and promotes the “rest and digest” state where we carry on digesting food and resting the body to bring stress chemicals down to normal.

Changes in the functioning of the stress systems with chronic exposure to stressors in our busy world are partly responsible for the development of fibro symptoms such as fatigue, depression and pain.  Of course it is important to mention that it is our perception of pain that causes depression and anxiety anyway because of its chronic nature.

However, although there is a role in the HPA Axis stress systems and the symptoms of chronic pain conditions, it does not follow that these systems are necessarily the cause of the symptoms themselves.

Neurotransmitters

Stress-related changes in other physiological areas of the body like neurotransmitter systems may be additionally involved in producing the symptoms of fibro.

Neurotransmitters are chemical messengers that carry chemical signals from one nerve cell (neuron) to the next target cell, which can be another nerve cell, a gland or a muscle cell.

This makes sense since we are told that fibro is the interaction between our brain, our nervous system and our muscles.

Serotonin

Serotonin is a neurotransmitter, (sometimes considered a hormone) and is our “feel good” substance.  It affects things such as mood, emotions, appetite and digestion and when it is deficient (which happens to fibro warriors) it causes anxiety, depression, digestive disorders and is thus strongly linked to fibro, being a chronic pain condition.

Dopamine 

Dopamine is a neurotransmitter/hormone that plays an important part in body functions including movement, memory and pleasurable reward/motivation.

Recent studies have given evidence that dopamine may also be involved in pain modulation, and the study hypothesised that fibro may involve disturbances in dopaminergic neurotransmission.  

How this was established was by fibro patients and healthy subjects being injected with hypertonic saline into anterior tibialis muscle. 

This measures the dopamine response to painful stimuli.  The control subjects released dopamine, whereas fibro subjects did not.

Noradrenaline

Noradrenaline (also known as norepinephrine) is a neurotransmitter and a hormone and is involved in our “fight or flight” response.

Fibro patients have noradrenaline-evoked pain, that supports the hypothesis that stress states are involved in fibro symptoms.

The reason is that noradrenaline is directly related to pain inhibition, and fibro is a chronic pain condition.

Substance P

Substance P is another neurotransmitter involved in pain perception by altering cellular signalling pathways. 

Substance P also plays a role in gastrointestinal functions, memory processing, angiogenesis (blood cell formation), vasodilation (widening blood vessels to enhance blood flow to areas lacking in oxygen), cell growth and proliferation.

Fibro patients have shown elevated levels of substance P in their cerebrospinal fluid.

One study found that fibro patients had 3 times more substance P than normal controls, but only weakly correlated to tenderness upon examination of such subjects.  Although this is a significantly breakthrough for fibro clinical findings, other abnormalities must exist to more fully explain the symptoms. 

Endorphins

Endorphins are chemicals (hormones) the body releases when pain or stress is experienced.  Endorphins are our natural suppressors of pain and play an important part in our sense of wellbeing.  Endorphins are released when we exercise, eat and have sexual contact, which is why we feel good in these situations.

In fibro, it is thought that these endorphins are being blocked and are thus low, and this contributes to both pain levels and the decreased ability to exercise. 

Conclusion

I have something to share with you all, it is extremely difficult to explain but I will try.  I have been trying to explain to my husband why I have several episodes throughout the year when, for a few moments, I feel out of sync with my life.

I am totally in control of my actions, I feel physically fine, but for up to a few minutes I don’t know why I am doing what I am doing, I don’t know what is happening, only that it is, and I am left feeling low and confused for a day or so afterwards.

I don’t worry about it, I recognise when it is happening and I just know it will happen again.  It is not like my brain fog that I get all the time, when I forget words, or stop speaking mid sentence.

It is like disorientation, but I am in control, it is like confusion, but I know what I am doing in the moment, it is like an absence yet I carry on functioning fully aware, and it is very strange. 

I had an MRI scan a few years ago for headaches I was having and there is nothing in the brain to suggest anything causing this, and I did not mention it to the neurologist, as I couldn’t explain it, so that is why I don’t worry. 

I only mention this as my husband immediately said it could be my fibro because of the brain involvement, and that prompted me to write the above to try and shed light on it.

Maybe some of you experience something similar?

Happy pain free month!