Evidence browser

Free-water-corrected diffusion and adrenergic/muscarinic antibodies in myalgic encephalomyelitis/chronic fatigue syndrome.

Kimura, Yukio, Sato, Wakiro, Maikusa, Norihide et al.·Journal of neuroimaging : official journal of the American Society of Neuroimaging·2023

Researchers used a specialized brain imaging technique to look for signs of inflammation in the brains of ME/CFS patients and compared these findings to levels of harmful antibodies (immune proteins) in their blood. They found that certain antibodies were linked to visible changes in a specific brain region called the right frontal operculum, and that longer disease duration was associated with more brain changes. These findings suggest that ME/CFS may involve both immune system dysfunction and measurable changes in brain structure.

Neuroinflammation

Increased gut permeability and bacterial translocation are associated with fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome: implications for disease-related biomarker discovery.

Martín, Franz, Blanco-Suárez, Manuel, Zambrano, Paola et al.·Frontiers in immunology·2023

This study found that people with ME/CFS and fibromyalgia may have a 'leaky gut'—where the intestinal barrier doesn't work as well as it should. Researchers measured several substances in the blood that indicate gut barrier problems and inflammation, and found higher levels in both patient groups compared to healthy people. These findings suggest that gut dysfunction might play a role in these conditions and could eventually help doctors identify and understand these diseases better.

Immune System

An international survey of experiences and attitudes towards pacing using a heart rate monitor for people with myalgic encephalomyelitis/chronic fatigue syndrome.

Clague-Baker, Nicola, Davenport, Todd E, Madi, Mohammad et al.·Work (Reading, Mass.)·2023

This study asked 488 people with ME about their experiences using heart rate monitors to help manage their activity levels. Heart rate monitors can help you stay within a safe activity zone that doesn't trigger post-exertional malaise (the worsening of symptoms after activity). Most people in the study found that heart rate monitors helped them understand their condition better, reduce symptom severity, and even gradually increase what they could do—including returning to some work. However, people also reported challenges, so more research and better training for doctors is needed.

E2 ModerateCohortPEM requiredLongitudinal

Long-term symptom severity and clinical biomarkers in post-COVID-19/chronic fatigue syndrome: results from a prospective observational cohort.

Legler, Franziska, Meyer-Arndt, Lil, Mödl, Lukas et al.·EClinicalMedicine·2023

This study followed 106 people with long-term fatigue after COVID-19 for up to 20 months to see how they recovered over time. Researchers found that some patients met the diagnostic criteria for ME/CFS and had persistent, severe symptoms including fatigue and post-exertional malaise (worsening after activity), while others improved more substantially. Lower muscle strength at the start of illness was linked to ongoing symptoms, especially in those with ME/CFS.

BiomarkersImmune SystemPost-Exertional Malaise

Health system support among patients with ME/CFS in Switzerland.

Tschopp, Rea, König, Rahel S, Rejmer, Protazy et al.·Journal of Taibah University Medical Sciences·2023

This Swiss study surveyed 169 ME/CFS patients to understand their experiences with the healthcare system. Patients faced long delays in getting diagnosed (averaging 6.7 years), saw many doctors before getting correct answers (11.1 appointments on average), and were frequently told their symptoms were psychological rather than physical. The study found that doctors in Switzerland lack knowledge about ME/CFS, leading to frustration, inappropriate treatments, and some patients traveling abroad for proper diagnosis.

Diagnostics

E2 ModerateCohortPEM unclearLongitudinal

COVID-19: Post-recovery Manifestations.

Shaikh, Safia, Siddiqi, Zunaira, Ukachukwu, Crystal et al.·Cureus·2023

This study asked nearly 200 people recovering from COVID-19 about their symptoms. Most patients (85%) reported ongoing problems after infection, with fatigue being the most common complaint (59%). Other frequent problems included reduced physical stamina (49%), shortness of breath (33%), and anxiety (24%). The symptoms resembled those seen in ME/CFS, though the study did not confirm a direct connection.

Different risk factors distinguish myalgic encephalomyelitis/chronic fatigue syndrome from severe fatigue.

Palacios, Natalia, Molsberry, Samantha, Fitzgerald, Kathryn C et al.·Scientific reports·2023

This study examined whether ME/CFS is simply an extreme version of regular fatigue, or if it's a fundamentally different condition. Researchers surveyed over 41,000 nurses and found that ME/CFS and severe fatigue have different risk factors—meaning different things cause them. This suggests that ME/CFS is a distinct condition with its own underlying biology, not just 'really bad tiredness.'

Diagnostics

E2 ModerateCohortPEM unclearObservational

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and COVID-19: is there a connection?

AlMuhaissen, Suha, Abu Libdeh, Amal, ElKhatib, Yara et al.·Current medical research and opinion·2023

This study looked at whether people who had COVID-19 might develop ME/CFS afterward. Researchers asked 437 people who had COVID-19 questions based on the official diagnostic criteria for ME/CFS. They found that about 8% of COVID-19 patients met the criteria for ME/CFS, suggesting there may be a connection between the two illnesses.

Diagnostics

Skin Temperature Circadian Rhythms and Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Role of Endothelin-1 in the Vascular Tone Dysregulation.

Cambras, Trinitat, Zerón-Rugerio, Maria Fernanda, Díez-Noguera, Antoni et al.·International journal of molecular sciences·2023

This study looked at how the bodies of people with ME/CFS respond to position changes and whether problems with their blood vessel function might be involved. Researchers compared 67 women with ME/CFS to 48 healthy women, measuring their blood pressure, heart rate, body temperature patterns, and blood markers related to blood vessel health. They found that people with ME/CFS had higher blood pressure and heart rate, disrupted daily temperature rhythms, and elevated levels of substances in the blood that suggest blood vessel problems.

Autonomic Nervous System

E2 ModerateCohortPEM unclearObservational

Adults with ME/CFS report surprisingly high rates of youth symptoms: A qualitative analysis of patient blog commentary.

Johnson, Madeline, Torres, Chelsea, Watts-Rich, Halli et al.·Work (Reading, Mass.)·2023

This study asked adults with ME/CFS about whether they experienced symptoms during childhood. Researchers analyzed comments from patients on a popular blog forum and found that about 43% of adults reported having ME/CFS before age 18. The study identified common themes in patients' stories, including mental health struggles, family history of illness, feeling misunderstood by others, and difficulties at school.

Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome.

Friedberg, Fred, Adamowicz, Jenna L, Bruckenthal, Patricia et al.·Scientific reports·2023

This study looked at how men and women with ME/CFS respond differently to a simple exercise test (a six-minute walk). Researchers tracked fatigue levels and heart function for 15 days in 37 ME/CFS patients and 14 healthy people. Women with ME/CFS felt more tired after the first walk test, while men reported fewer work limitations in the days after exercise. Surprisingly, the study did not find the expected differences between men and women in how long it took to recover.

E2 ModerateDiagnosticPEM requiredCross-Sectional

Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition.

Conroy, Karl E, Islam, Mohammed F, Jason, Leonard A·Disability and rehabilitation·2023

This study looked at how doctors diagnose ME/CFS by analyzing symptoms reported by over 2,300 patients from around the world. Researchers used statistical methods to identify which symptoms tend to occur together, then compared their findings to three existing diagnostic guidelines. They found that the symptoms cluster into seven main groups, with post-exertional malaise (worsening after activity), cognitive problems, and sleep issues being particularly important.

SleepPost-Exertional Malaise

E2 ModerateCohortPEM unclearObservational

Utility of Serum Ferritin for Predicting Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Patients with Long COVID.

Yamamoto, Yukichika, Otsuka, Yuki, Tokumasu, Kazuki et al.·Journal of clinical medicine·2023

This study looked at 234 people with long COVID to understand why some developed ME/CFS (a severe fatigue condition) while others didn't. Researchers found that people who developed ME/CFS had significantly higher levels of ferritin, a protein that stores iron, in their blood compared to those with long COVID fatigue alone or no fatigue. The finding was especially strong in women, suggesting that a simple blood test measuring ferritin might help predict who is at risk of developing ME/CFS after COVID-19.

Biomarkers

Do diagnostic criteria for ME matter to patient experience with services and interventions? Key results from an online RDS survey targeting fatigue patients in Norway.

Kielland, Anne, Liu, Jing, Jason, Leonard A·Journal of health psychology·2023

This study surveyed 660 people with ME/CFS in Norway to understand how different diagnostic criteria and symptoms affect their experiences with treatments and healthcare services. Most patients reported that available interventions had little benefit or made them feel worse. The researchers found that post-exertional malaise (a hallmark symptom where activity makes fatigue and other symptoms worse) was strongly linked to how patients tolerated different treatments, suggesting this symptom should be a key consideration when recommending interventions.

Orthostatic chronotropic incompetence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

van Campen, C Linda M C, Verheugt, Freek W A, Rowe, Peter C et al.·IBRO neuroscience reports·2023

This study looked at how ME/CFS patients' hearts respond when they stand up or tilt upright during a medical test. Normally, when you stand, your heart rate increases to maintain blood flow to your brain. Researchers found that many ME/CFS patients had an incomplete heart rate increase despite their blood flow dropping significantly—a condition called chronotropic incompetence. This problem was more common in patients with more severe ME/CFS.

Autonomic Nervous System

E2 ModerateCohortPEM not requiredCross-Sectional

Circulating miRNAs Expression in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Soffritti, Irene, Gravelsina, Sabine, D'Accolti, Maria et al.·International journal of molecular sciences·2023

Researchers tested whether six small molecules called microRNAs (miRNAs) in the blood could help identify people with ME/CFS. They compared blood samples from 40 ME/CFS patients with 20 healthy people and found that five miRNAs were more abundant in patients' blood while one was less abundant. Interestingly, the levels of these molecules matched how severe each patient's symptoms were, suggesting they could potentially be used as a blood test to help diagnose ME/CFS.

Biomarkers

Post-COVID sequelae effect in chronic fatigue syndrome: SARS-CoV-2 triggers latent adenovirus in the oral mucosa.

Hannestad, Ulf, Apostolou, Eirini, Sjögren, Per et al.·Frontiers in medicine·2023

This study found that people with ME/CFS who caught COVID-19 showed signs of a dormant virus (adenovirus) waking up in their mouth and throat. The researchers compared saliva samples from ME/CFS patients and healthy people, and only the ME/CFS patients showed this reactivation after COVID-19 infection. This suggests that ME/CFS patients may have a weakened immune system that cannot keep these latent viruses under control when faced with a new infection like COVID-19.

Immune System

E2 ModerateCohortPEM not requiredObservational

A distinctive profile of family genetic risk scores in a Swedish national sample of cases of fibromyalgia, irritable bowel syndrome, and chronic fatigue syndrome compared to rheumatoid arthritis and major depression.

Kendler, Kenneth S, Rosmalen, Judith G M, Ohlsson, Henrik et al.·Psychological medicine·2023

This study looked at the family histories of over 5 million Swedish people to understand whether ME/CFS, fibromyalgia, and irritable bowel syndrome share common genetic roots. Researchers found that people with these conditions have a distinctive pattern of genetic risk that affects multiple body systems—including pain, mood, immune function, and sleep—rather than being limited to one specific area like depression or rheumatoid arthritis. This suggests these functional somatic disorders may arise from a complex genetic vulnerability affecting several interconnected systems rather than a single cause.

E2 ModerateCohortPEM not required

Hypothalamus volumes in adolescent Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): impact of self-reported fatigue and illness duration.

Byrne, Hollie, Josev, Elisha K, Knight, Sarah J et al.·Brain structure & function·2023

This study looked at the size of the hypothalamus (a small part of the brain that controls many body functions) in teenagers with ME/CFS compared to healthy teenagers. While the overall brain structure sizes were similar between the two groups, researchers found that in ME/CFS patients, certain areas of the hypothalamus were slightly larger when fatigue was more severe, and other areas grew larger with longer illness duration. This suggests the hypothalamus may play a role in ME/CFS, though more research is needed to understand what this means.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome is common in post-acute sequelae of SARS-CoV-2 infection (PASC): Results from a post-COVID-19 multidisciplinary clinic.

Bonilla, Hector, Quach, Tom C, Tiwari, Anushri et al.·Frontiers in neurology·2023

This study looked at 140 people suffering from long COVID symptoms and found that nearly half of them (43%) met the medical criteria for ME/CFS. Most patients had severe fatigue, brain fog, and unrefreshing sleep that lasted around 9-10 months on average. People with higher body weight and greater functional decline were more likely to develop the ME/CFS form of long COVID.