Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Neurological Entity?

Observed Findings

• Brain imaging studies reveal multiple types of alterations (structural, functional, metabolic, and connectivity-related) in ME/CFS patients, though these lack diagnostic specificity.
• Heart rate variability abnormalities, abnormal responses to the Valsalva maneuver, and abnormal tilt table test results were documented in subgroups of patients.
• Serum autoantibodies against adrenergic, cholinergic, and serotonin receptors were found in some ME/CFS patients.
• The COMPASS-31 questionnaire effectively identifies patients with suspected dysautonomia warranting further specialized evaluation.
• ME/CFS symptoms characteristically include "central" fatigue with physical and/or mental exhaustion disproportionate to effort expended.

Inferred Conclusions

• ME/CFS qualifies as a neurological disorder with primary involvement of the autonomic nervous system, supporting its ICD-11 classification.
• Dysautonomia assessment conducted in specialized units shows greater promise than neuroimaging alone for supporting diagnosis and identifying biomarkers.
• Patient heterogeneity in ME/CFS suggests multiple phenotypes identifiable through combined autonomic and immune testing.
• Functional rather than structural pathology likely characterizes ME/CFS in most patients.

Remaining Questions