Fibromyalgia – a chronic condition that causes pain in the joints and muscles and even all over the body, sleep problems, fatigue and often emotional and mental distress – is so misunderstood even by doctors that many think patients are in fact suffering from mental conditions. 

It is not considered an emotional illness, but many people with fibromyalgia also experience depression and/or anxiety. Many doctors lack adequate knowledge of the criteria for the diagnosis of fibromyalgia. 

It is often triggered by a stressful event, including physical or psychological stress, but other possible triggers for the condition include an injury or a viral infection. Doctors may not immediately consider fibromyalgia when evaluating these types of symptoms, because pain is also common with many other conditions. That’s one reason why it takes an average of five years for people with this disorder to get diagnosed.

Now, a new study conducted by scientists at Rambam Medical Center in Haifa and McGill University in Quebec has found changes in women’s blood bile acids that are connected to the gut microbiome. Their research could provide a new molecular methodology for diagnosing fibromyalgia.

Affecting around four per cent of the population and mostly women, it has no cure. But the scientists at Rambam’s Institute for Pain Medicine and the Research Institute of McGill University have been researching the condition and made some important new discoveries.

Already in 2019, the research team had found indications that the gut microbiome – a community of microorganisms found in the digestive tract – played a role in chronic pain, including that experienced in fibromyalgia. Now, the same team, including Rambam’s Dr. Amir Minerbi and Dr. Nicholas Bereton from the University of Montreal and McGill University researchers Emmanuel Gonzalez, Mary-Ann Fitzcharles, Stéphanie Chevalier and Yoram Shir have made new discoveries that could lead to a clear diagnosis of fibromyalgia. 

Entitled “altered serum bile-acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity” and published in the journal Pain, their research presents the first evidence that women with fibromyalgia have different amounts and species of bile-metabolizing gut bacteria and different bile acid concentrations in the blood, compared to healthy people. They also found that some of these differences correlated with symptom severity. 

“The change in bile acids that we observed in patients with fibromyalgia in our study is distinct enough to be used as an effective biological signature to detect individuals with fibromyalgia. That’s an important step forward, considering that diagnosing fibromyalgia is often a long process that requires eliminating other conditions that can cause similar symptoms,” noted Minerbi, who recently returned to Rambam’s Institute for Pain Medicine after an extended time in at McGill University Health Center.

Using artificial intelligence, the team also found that the presence of six specific secondary bile acids was more than 90 percent accurate in predicting if a study participant had fibromyalgia.

“Machine and statistical learning have helped us to characterize which gut bacteria change in abundance and which human bile acids are important makers of the disease,” added Dr. Emmanuel Gonzalez, from the Canadian Center for Computational Genomics and the human genetics at McGill. “These approaches provided an accurate biological signature of fibromyalgia. Although our study cohort was relatively small, these findings are a promising sign that artificial intelligence might be able to considerably enhance accurate diagnosis of the disease.”

“Our findings show a strong relationship between patient microbiome composition, bile acids and the severity of fibromyalgia symptoms. Understanding the biological mechanism of fibromyalgia is critical, because it shows that this condition is real, and because it brings us closer to developing an effective treatment to these women and men in pain,” said Shir.