Tag: muscle abnormalities

31P-mr spectroscopy of peripheral skeletal musculature under load: demonstration of normal energy metabolites compared with metabolic muscle diseases

Abstract:

PURPOSE: 31P-MR spectroscopy of skeletal muscle under exercise was used to obtain the range of normal variation and comparison was made for different neuromuscular diseases.

METHODS: 41 examinations of 24 volunteers and 41 investigations in 35 patients were performed on 1.5 T MR systems (Gyroscan 515 und S15/ACSII, Philips). Localised 31P-MR spectra of the calf muscle were obtained in time series with a resolution of 12 s.

RESULTS: Two types of muscle energy metabolism were identified from the pattern of spectroscopic time course in volunteers: While the first group was characterised by a remarkable decline to lower pH values during exercise, the second group showed only small pH shifts (minimum pH: 6.48 +/- 0.13 vs 6.87 +/- 0.07, p < 10(-6)) although comparable workload conditions were maintained. The pH-values correlated well with blood lactate analysis. Patients with metabolic disorders and chronic fatigue syndrome (CFS) showed decreased resting values of PCr/(PCr + Pi) and increased pH levels during exercise. PCr recovery was significantly delayed (0.31 vs 0.65 min-1, p < 0.00005) in metabolic muscle disorders but was normal in CFS patients.

CONCLUSION: Findings in volunteers indicate utilisation of different metabolic pathways which seems to be related to the fibre type composition of muscle. Reduced resting levels for PCr/(PCr + Pi), altered pH time courses, and decreased PCr recovery seem to be helpful indicators for diagnosis of metabolic muscle disorders.

Source: Block W, Träber F, Kuhl CK, Keller E, Lamerichs R, Karitzky J, Rink H, Schild HH. 31P-mr spectroscopy of peripheral skeletal musculature under load: demonstration of normal energy metabolites compared with metabolic muscle diseases. Rofo. 1998 Mar;168(3):250-7. [Article in German] http://www.ncbi.nlm.nih.gov/pubmed/9551111

Chronic fatigue: electromyographic and neuropathological evaluation

Abstract:

Single fibre electromyography of extensor digitorum communis muscle (EDC) was performed on 35 patients with chronic fatigue, the majority of whom also had creatine kinase estimation and biopsy of EDC.

The subjects were categorised as having an acute-onset post-viral fatigue syndrome, a non-specific chronic fatigue or possible muscle disease in view of pronounced myalgia.

Of 11 subjects who had myalgia as a significant symptom, abnormalities in fibre density were found in 6, and 5 of these had some non-specific abnormalities on muscle biopsy, with creatine kinase levels being normal in all cases. Fibre density estimation may be a useful way of identifying a subgroup of chronic fatigue sufferers with a possible primary muscle disorder.

 

Source: Connolly S, Smith DG, Doyle D, Fowler CJ. Chronic fatigue: electromyographic and neuropathological evaluation. J Neurol. 1993 Jul;240(7):435-8. http://www.ncbi.nlm.nih.gov/pubmed/8410086

 

Chronic fatigue syndrome: a joint paediatric-psychiatric approach

Comment on: Chronic fatigue syndrome: a joint paediatric-psychiatric approach. [Arch Dis Child. 1992]

 

SIR,-While agreeing that physical, psychological, and social factors must all be taken into account in the management of this complex and controversial syndrome I would disagree with Dr Margaret Vereker’s statement that no organic pathology can be detected to account for any of the symptoms. This conclusion has been made without reference to a number of research papers describing persisting viral infection, neuromuscular abnormalities in both structure and function, and immune system dysfunction.

Gow et al using polymerase chain reaction techniques, have been able to demonstrate the presence of enteroviral genome in muscle biopsies from a significant number of patients (53%) compared with controls (15%). None of the healthy control group in this study had evidence of viral particles in their muscle, this was only found in those with colonic or breast malignancies. Precisely what cytopathological effect this intracellular virus is having within muscle remains open to debate. However, Behan et al have published electron microscopic evidence of structural damage to the muscle mitochondria along with type II fibre atrophy; this is a finding which is not normally considered to be consistent with simple disuse.

You can read the rest of this letter here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1793782/pdf/archdisch00632-0102a.pdf

 

Source: Shepherd C. Chronic fatigue syndrome: a joint paediatric-psychiatric approach. Arch Dis Child. 1992 Nov;67(11):1410. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1793782/

 

Post-viral fatigue syndrome: evidence for underlying organic disturbance in the muscle fibre

Abstract:

Ten patients with post-viral fatigue syndrome and abnormal serological, virological, immunological and histological studies were examined by the single-fibre electromyographic (EMG) technique after excluding concurrent problems in the neuromuscular system. No abnormality of fibre density was noted but all patients had abnormal jitter values. Very high jitter values were not associated with impulse or concomitant blocking. The findings confirm the organic nature of the disease. A muscle membrane disorder probably arising from defective myogenic enzymes is the likely mechanism for the fatigue and the single-fibre EMG abnormalities. This muscle membrane defect may be due to the effects of a persistent viral infection.

 

Source: Jamal GA, Hansen S. Post-viral fatigue syndrome: evidence for underlying organic disturbance in the muscle fibre. Eur Neurol. 1989;29(5):273-6.  http://www.ncbi.nlm.nih.gov/pubmed/2792146