Diagnosing Fibromyalgia

Doctors are usually able to confirm whether or not you have a certain medical condition by using blood tests, X-Rays or other scans. Diagnosing fibromyalgia syndrome (FMS), on the other hand, is a far more difficult process, given that most standard medical tests do not reveal any abnormalities. The likelihood of getting a quick and correct diagnosis varies significantly based on a number of factors.

How is it diagnosed?

The way that diagnosis is confirmed depends largely on the country that you live in, and the individual views of the doctor that you see. In 1990, the American College of Rheumatology (ACR) developed a set of diagnostic criteria for FMS, which were then updated in 2010[1]. This is a standardised test with two sections:

• 1. The ‘widespread pain index’ – where sites that you experience pain are noted.
• 2. The ‘symptoms severity scale’, where a list of other common symptoms of FMS is recorded.

A diagnosis according to these criteria is based on your scores on these two parts, and, although not perfect, the questionnaire has been shown to have good accuracy and consistency.

Does everyone use it?

No, and this is where it becomes more complicated. Although the ACR criteria have been taken up by many countries (Japan, France, Spain etc.), many other places, including the U.K, do not use this as standard, instead opting for what is known as a ‘clinical diagnosis’.

A clinical diagnosis is one that is based on the opinion of the doctor, rather than any specific test, and is used for a number of conditions. Doctors will often send patients for tests to rule out other possible causes of their symptoms, and diagnose FMS based on the absence of any other positive results. This sounds reasonable, but research suggests that the accuracy of this method is poor when compared to the ACR criteria[2], leading to missed diagnoses in many cases.

Why the discrepancy?

To understand why FMS diagnosis is so inconsistent, some history is required. FMS has been described for centuries under various names, and with a host of different theories proposed for why it occurs. As medical testing became more sophisticated in the 20^th century, the majority of these theories were disproved, as doctors came to realise that blood tests and scans of people suspected to have FMS failed to show any abnormal results. This led to scepticism of whether FMS was even a real condition, with patients accused of malingering or making a fuss about nothing. Despite more recent advances in neural imaging now showing clear differences in the brain activity of FMS patients, this old scepticism still remains in many corners of the medical world. Research from Norway, for example, showed that FMS was the disease that was viewed as having the lowest prestige by doctors, meaning that they take it less seriously than other, similar conditions[3].

This perceived lack of importance has translated into a lack of research and poorer knowledge of the condition amongst many doctors[4], meaning that the process of getting a diagnosis can often take many years. Not only is this frustrating for patients, it also leads to delays in getting them the help and support that they require. Research suggests that not only does a diagnosis legitimise a person’s symptoms and provide them with reassurance, it also helps them to cope better with those symptoms[5].

What is the solution?

Advances in the sensitivity of testing may mean that one day FMS is easily detectable. A team of researchers in America are working on a new type of blood test, which has shown promising results. This is now being offered to patients in some places in the world, however more trials are needed to investigate just how reliable this is.

For the time being, the best that we can hope for is that doctors around the world can find a way to agree on the best way to diagnose FMS. Action is also required to improve knowledge of the condition amongst physicians, as the current low status of FMS causes frustration and costly delays for patients.

At rTMS London, we believe that the ACR criteria are currently the best method available to confirm a diagnosis of FMS, and as such we use this as standard when assessing all of our patients. We are keeping a close eye on the results of the new blood test trial however, as a combination of this and the ACR criteria may very well become the gold standard for diagnosing FMS.

To view the diagnostic criteria yourself, click here.

---

[1] Wolfe, F., et al (2011). Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR Preliminary Diagnostic Criteria for Fibromyalgia. The Journal of rheumatology, 38(6), 1113–1122. https://doi.org/10.3899/jrheum.100594

[2] Wolfe, F et al (2019). Diagnosis of Fibromyalgia: Disagreement Between Fibromyalgia Criteria and Clinician-Based Fibromyalgia Diagnosis in a University Clinic. Arthritis care & research, 71(3), 343–351. https://doi.org/10.1002/acr.23731

[3] Album, D., et al (2017). Stability and change in disease prestige: A comparative analysis of three surveys spanning a quarter of a century. Social science & medicine (1982), 180, 45–51. https://doi.org/10.1016/j.socscimed.2017.03.020

[4] Kianmehr, N., et al. (2017). Are general practitioners well informed about fibromyalgia?. International journal of rheumatic diseases, 20(12), 1917–1921. https://doi.org/10.1111/1756-185X.12716

[5] Häuser, W., et al (2019). Fibromyalgia syndrome: under-, over- and misdiagnosis. Clinical and experimental rheumatology, 37 Suppl 116(1), 90–97.

Posted on 25th November 2021