Journal of Neurology, Neurosurgery, and Psychiatry 1987;50:743-746 Chronic fatigue and myalgia syndrome: mitochondrial and glycolytic studies in skeletal muscle

SUMMARY Clinical and biochemical findings in skeletal muscle in 11 patients with chronic fatigue myalgia syndromes of unknown aetiology are reported. All patients had severe asthenia for from one to 10 years with greatly limited exercise capacity and protracted exhaustion after minor exercise. Diffuse myalgia was prominent and was exacerbated for hours to days after exercise. Assay of skeletal muscle carnitine, phosphorylase, all glycolytic enzymes and the mitochondrial marker enzymes monoamine oxidase, isocitrate dehydrogenase and cytochrome oxidase were normal. These findings lend no support to the presence of a major defect in muscle intermediary energy pathways in this syndrome. Severe asthenia and myalgia of obscure aetiology and protracted course is a common problem and has been designated as post viral fatigue syndrome, ' epidemic myalgic encephalomyelitis,2 epidemic neuromy-asthenia3 and Royal Free disease. Sporadic cases are more common than epidemic cases ' and there is con-siderable dispute as to whether this disorder has an organic or a psychogenic basis. ' 4 s Defects in inter-mediary muscle metabolism are well recognised as causes of both fatigability and myalgia. Mito-chondrial deficiencies may be associated with promi-nent fatigability6-8 and exercise induced myalgia characterises disorders of glycogenolysis and gly-colysis.9 12 Although the clinical features of the chronic fatigue and myalgia syndrome differ from those of well estab-lished deficiences in intermediary energy metabolism, the possibility merits consideration that a subtle met-abolic derangement may have a pathogenic role in this syndrome. Recent MRI studies have provided some support for this postulate.'3 The possibility of a deficiency in intermediary energy pathways was explored in this study by assay of muscle glycolytic and mitochondrial marker enzymes, phosphorylase and carnitine in a group of 11 patients