Enterovirus related metabolic myopathy: a postviral fatigue syndrome

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 74; no. 10; pp. 1382 - 1386
• Main Authors: Lane, R J M, Soteriou, B A, Zhang, H, Archard, L C
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.10.2003; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adult; Anaerobic threshold; Biological and medical sciences; Biopsy; Causes of; CFS; Chronic fatigue syndrome; Diseases of striated muscles. Neuromuscular diseases; DNA, Viral - analysis; Enterovirus - genetics; Enterovirus - pathogenicity; Enterovirus B, Human - genetics; Enterovirus B, Human - pathogenicity; enterovirus RNA sequences; Enteroviruses; Exercise; Exercise - physiology; Exercise Test; Fatigue Syndrome, Chronic - etiology; Fatigue Syndrome, Chronic - virology; Female; Humans; Infections; Influence; Laboratories; Lactic acid; Lactic Acid - metabolism; Male; Medical sciences; Middle Aged; Muscle diseases; muscle energy metabolism; Muscle, Skeletal - pathology; Muscle, Skeletal - physiology; Muscle, Skeletal - virology; Muscular Diseases - metabolism; Muscular Diseases - virology; Myocarditis; nested polymerase chain reaction; Neurology; Physical Endurance; Physiological aspects; Polymerase chain reaction; postviral fatigue syndrome; Reverse Transcriptase Polymerase Chain Reaction; reverse transcription; RT-NPCR; SATET; subanaerobic threshold exercise test; Viral infections; Viruses; United Kingdom; United Kingdom > UK; Physical exercise; Human; Energy metabolism; Pathophysiology; RNA; Picornaviridae; Pathogenesis; Enterovirus; Chronic fatigue syndrome; Virus; Lactates; Striated muscle disease; Quadriceps muscle
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp.74.10.1382

Objective: To detect and characterise enterovirus RNA in skeletal muscle from patients with chronic fatigue syndrome (CFS) and to compare efficiency of muscle energy metabolism in enterovirus positive and negative CFS patients. Methods: Quadriceps muscle biopsy samples from 48 patients with CFS were processed to detect enterovirus RNA by two stage, reverse transcription, nested polymerase chain reaction (RT-NPCR), using enterovirus group specific primer sets. Direct nucleotide sequencing of PCR products was used to characterise the enterovirus. Controls were 29 subjects with normal muscles. On the day of biopsy, each CFS patient undertook a subanaerobic threshold exercise test (SATET). Venous plasma lactate was measured immediately before and after exercise, and 30 minutes after testing. An abnormal lactate response to exercise (SATET+) was defined as an exercise test in which plasma lactate exceeded the upper 99% confidence limits for normal sedentary controls at two or more time points. Results: Muscle biopsy samples from 20.8% of the CFS patients were positive for enterovirus sequences by RT-NPCR, while all the 29 control samples were negative; 58.3% of the CFS patients had a SATET+ response. Nine of the 10 enterovirus positive cases were among the 28 SATET+ patients (32.1%), compared with only one (5%) of the 20 SATET− patients. PCR products were most closely related to coxsackie B virus. Conclusions: There is an association between abnormal lactate response to exercise, reflecting impaired muscle energy metabolism, and the presence of enterovirus sequences in muscle in a proportion of CFS patients.