Systemic Exertion Intolerance Disease (SEID)

‍Introduction to SEID

Systemic Exertion Intolerance Disease (SEID) was proposed as a new diagnostic term for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) by the Institute of Medicine (IOM) in 2015. While the intention was to create a name that reflects the central characteristics of the illness, the term SEID has not been widely adopted. ME/CFS continues to be the terminology used by organizations like the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH). This article explores the IOM’s proposed criteria, the debate surrounding SEID, and its implications for clinical practice and research.

Diagnostic Criteria

The IOM proposed new criteria in its 2015 report, aiming to simplify and improve the diagnostic process. The criteria require three core symptoms:

1. Fatigue lasting more than six months: Unlike ordinary tiredness, this fatigue is severe, not alleviated by rest, and is not the result of excessive exertion.
2. Post-exertional malaise (PEM): A worsening of symptoms following physical or mental activity.
3. Unrefreshing sleep: Persistent and debilitating despite adequate rest.

In addition to these, patients must exhibit either cognitive impairment or orthostatic intolerance. Symptom severity and frequency are critical in diagnosis, with symptoms needing to be present at least half the time with moderate to severe intensity.

Comparison with Other Criteria

The SEID criteria simplify the diagnosis compared to the Canadian Consensus Criteria (CCC) and International Consensus Criteria (ICC). However, this streamlining has sparked debate over whether essential symptoms, like immune dysfunction, were excluded in the process.

Symptoms of SEID

SEID’s core symptoms reflect the hallmark features of ME/CFS. However, the condition also includes a range of associated symptoms:

• Pain: Muscle aches, joint pain without swelling, and severe headaches are common.
• Flu-like symptoms: Tender lymph nodes, sore throat, and night sweats.
• Sensitivities: Heightened reactions to light, noise, chemicals, and certain foods.
• Gastrointestinal issues: Many patients report symptoms of irritable bowel syndrome (IBS).

Orthostatic intolerance, marked by symptoms that worsen when standing, further highlights the systemic nature of the illness.

Development of the SEID Concept

The IOM’s criteria arose from a collaborative effort by federal health agencies, including the CDC and NIH, to improve the diagnosis and care of ME/CFS. The IOM report, titled Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness, aimed to address inconsistencies in prior diagnostic frameworks.

The report proposed renaming ME/CFS to SEID, emphasizing the disease’s hallmark feature: intolerance to exertion. However, the name failed to gain traction among government and advocacy organizations, many of which viewed it as a step backward in understanding the condition.

Criticisms of the IOM Criteria

The IOM criteria faced significant backlash from the ME/CFS community. Critics argued that:

• Too Few Symptoms Were Required: Key features like immune and neurological dysfunction were downplayed compared to earlier diagnostic frameworks.
• Unclear Descriptions of PEM: While central to the diagnosis, the IOM’s description of PEM was considered vague.
• Pain as a Secondary Symptom: Pain, a common and disabling symptom, was listed as optional rather than a diagnostic requirement.

Researcher Frank Twisk further contended that SEID conflated ME and CFS, two potentially distinct illnesses, and risked misdiagnosing patients who did not meet established ME or CFS criteria.

Impact on Clinical Practice and Research

The SEID diagnostic criteria have been incorporated into the CDC’s guidelines, providing clinicians with tools to diagnose ME/CFS more effectively. However, adoption in clinical practice has been uneven due to limited awareness and ongoing debate over the criteria’s validity.

Research studies have utilized the IOM criteria to examine ME/CFS, but questions remain about the criteria’s ability to capture the illness’s full complexity. The lack of consensus has hindered progress in standardizing care and advancing treatments.

Conclusion

The IOM’s proposal of SEID sought to simplify and clarify the diagnosis of ME/CFS, but its reception underscores the challenges of redefining a complex illness. While the criteria have advanced discussions about ME/CFS, they also highlight the need for continued collaboration between researchers, clinicians, and patients to refine diagnostic tools.

Future efforts should prioritize inclusivity and precision to ensure that all patients receive accurate diagnoses and effective care. By addressing these challenges, the medical community can better meet the needs of those living with ME/CFS and related conditions.

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Additional Resources

• CDC Information for Healthcare Providers: Link to CDC guidelines

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FAQ

What is the new name for chronic fatigue syndrome?

The new name for chronic fatigue syndrome (CFS) is systemic exertion intolerance disease (SEID).

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