Researchers trying to fathom the causes of fibromyalgia

September 14, 2018 by Kevin Davies, Jessica Eccles And Neil Harrison, The Conversation
Credit: TierneyMJ/Shutterstock.com

Fibromyalgia is something of a mystery. It can't be detected with scans or blood tests, yet it causes lifelong pain for millions of people.

The disease mainly affects women (about 75-90 percent of cases), causing pain all over the body. Because not all healthcare professionals are adept at identifying and diagnosing fibromyalgia, reported rates of the condition vary greatly from country to country. In China, it affects only 0.8 percent of people, in France around 1.5 percent, in Canada 3.3 percent, and in Turkey 8.8 percent. Estimates in the US range from 2.2 percent to 6.4 percent, and in Russia, about 2 percent of the population is affected.

People with the condition are often diagnosed if they have longstanding muscle pain, bone or joint pain and fatigue. Fibromyalgia can also cause insomnia, "brain fog", some symptoms of depression or anxiety, as well as a range of other complaints, including and headache. Many patients are also hypermobile ("double-jointed"), and there is some overlap with chronic fatigue syndrome (also known as ME).

Guidelines from the American College of Rheumatology make it clear that the diagnosis should be made using defined criteria based on the "widespread pain index" (which scores the number of painful regions out of 19) coupled with a symptom severity scale. The diagnosis also takes fatigue, generalised pain, unrefreshing sleep and cognitive symptoms into account. It doesn't matter if the patient has another rheumatic disease, they can still be diagnosed with fibromyalgia.

The scoring system, recommended by the American College of Rheumatology, is often used in clinical trials, but in the clinic, most doctors rely on detecting tender points in specific places and on excluding other medical conditions, including rheumatic conditions. Unlike say, rheumatoid arthritis or lupus, the tests do not show clear evidence of inflammation or autoimmunity (when the body's immune system attacks itself) and scans are normal.

The lack of inflammation or structural abnormality in muscles or joints – aside from making diagnosis difficult – is the main reason there are no widely accepted or effective treatments. In rheumatic diseases, where we understand the mechanisms that underlie the condition, we have the most effective treatments. In rheumatoid arthritis, for example, we know that much of the inflammation is caused by a cell-signalling protein (cytokine) called and that blocking the activity of this protein switches off the disease in most patients.

Researchers trying to fathom the causes of fibromyalgia
Many people with fibromyalgia are hypermobile ( MatthewThomasWxm/Wikimedia Commons, CC BY-SA

A number of possible mechanisms have been proposed in fibromyalgia, including abnormal muscle metabolism, reduced levels of steroid hormones such as cortisol, or abnormal small nerve fibres. But these abnormalities aren't found in all patients with the condition. As such, they can't be used as part of a diagnostic test, nor can they help develop treatments.

Some experts have suggested that fibromyalgia may be related to abnormalities in the autonomic nervous system – the part of the nervous system that controls bodily functions, such as and blood pressure – and how the brain responds to pain signals and reacts to external stressors (such as infections). But there is currently no hard evidence to back up this theory.

Looking for clues

To fill in some of the gaps in our knowledge about this devastating condition, our research team at Brighton and Sussex Medical School is investigating the potential role of the autonomic nervous system and inflammation in fibromyalgia and chronic fatigue syndrome.

For our study, we have two groups of patients: one with pain as the main symptom and the other with fatigue as the main symptom. We also have matched controls – people without the disease, but otherwise similar characteristics – to make meaningful comparisons.

The study is in two parts. First, we will test the patients' autonomic nervous system using a tilt-table. This involves tilting the person head downwards to see how well their body adapts to this change in posture by changing heart rate and (both of which are monitored during the test).

Researchers trying to fathom the causes of fibromyalgia
A tilt-table test. Credit: Blamb/Shutterstock.com

Second, we will stimulate patients' immune systems with a typhoid vaccine (the normal type used in travellers) and perform magnetic resonance brain scans to look for changes in blood flow and also measure the levels of "inflammatory mediators" (the chemicals the body produces in response to stimuli of this type), to see whether these are higher in the fibromyalgia patients.

Our study should, for the first time, help us to address the question of whether there really is an abnormal brain response to inflammation or infection in these patient groups and enable us to explore the relationship between the abnormal functioning of the autonomic nervous system and and .

Fibromyalgia rarely goes away and treatment options are limited. Only by developing a proper understanding of the disease processes underlying this condition will doctors be able to make a clear, positive diagnosis, and most importantly, offer effective therapy.

Explore further: Link between DNA and chronic widespread joint pain

Related Stories

Link between DNA and chronic widespread joint pain

November 11, 2016
Scientists at King's College London, funded by the charity Arthritis Research UK, have found a link between changes in marks on the outside of DNA (epigenetics) and chronic widespread joint pain, one of the main symptoms ...

Screening women veterans with fibromyalgia for childhood abuse may improve treatment

August 8, 2018
A new study has shown that women Veterans being treated for fibromyalgia exhibit high rates of childhood abuse.

New research could lead to a blood test for common pain syndrome fibromyalgia

May 12, 2015
New UK research could lead to a blood test to diagnose the common pain condition, fibromyalgia.

Men with fibromyalgia often go undiagnosed, Mayo Clinic study suggests

December 19, 2012
Fibromyalgia is a complex illness to diagnose and to treat. There is not yet a diagnostic test to establish that someone has it, there is no cure and many fibromyalgia symptoms—pain, fatigue, problems sleeping and memory ...

Fibromyalgia and the role of brain connectivity in pain inhibition

October 1, 2014
The cause of fibromyalgia, a chronic pain syndrome is not known. However, the results of a new study that compares brain activity in individuals with and without fibromyalgia indicate that decreased connectivity between pain-related ...

Weather conditions do not affect fibromyalgia pain or fatigue

June 4, 2013
Dutch researchers report that weather conditions including temperature, sunshine, and precipitation have no impact on fibromyalgia symptoms in female patients. Results published in Arthritis Care & Research, a journal of ...

Recommended for you

Drugs that stop mosquitoes catching malaria could help eradicate the disease

September 18, 2018
Researchers have identified compounds that could prevent malaria parasites from being able to infect mosquitoes, halting the spread of disease.

Vaccine opt-outs dropped slightly when California added more hurdles

September 18, 2018
In response to spiking rates of parents opting their children out of vaccinations that are required to enroll in school—and just before a huge outbreak of measles at Disneyland in 2014—California passed AB-2109. The law ...

New evidence of a preventative therapy for gout

September 17, 2018
Among patients with cardiovascular disease, it's a common complaint: a sudden, piercing pain, stiffness or tenderness in a joint that lasts for days at a time with all signs pointing to a gout attack. Gout and cardiovascular ...

"Atypical" virus discovered to be driver of certain kidney diseases

September 14, 2018
An international research team led by Wolfgang Weninger has discovered a previously unknown virus that acts as a "driver" for certain kidney diseases (interstitial nephropathy). This "atypical" virus, which the scientists ...

Flu shot rates in clinics drop as day progresses, but nudges help give them a boost

September 14, 2018
Primary care clinics experienced a significant decline in influenza vaccinations as the day progressed, researchers from Penn Medicine report in a new study published in JAMA Open Network. However, "nudging" clinical staff ...

Cancer drug and antidepressants provide clues for treating brain-eating amoeba infections

September 13, 2018
The amoeba Naegleria fowleri is commonly found in warm swimming pools, lakes and rivers. On rare occasions, the amoeba can infect a healthy person and cause severe primary amebic meningoencephalitis, a "brain-eating" disease ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.