Naglaa A. Gadallah, Mohamed R. Awad, MD PhD, Klaus R. von Wild, MD PhD,
Hanan E. El-Hefnawy, Nadia H. El-Arousy, Nadia G. El-Hefnawy, Tarek A. Abdou,
Ehab A. El Shafie, Abeer K. El Zohiery
Jpn J Compr Rehabil Sci 4: 30-38, 2013
Objectives: Our aim was to assess peripheral neural
and muscular dysfunction in patients with fibromyalgia
syndrome (FMS) by interrelating different
electrophysiologic and histopathologic studies, in a
trial to further elucidate the pathophysiology of fatigue
in FMS.
Methods: Thirty FMS patients and ten controls were
enrolled in the study. To test for muscle fatigue, muscle
fiber conduction velocity (MFCV) and quantitative
surface EMG analysis were performed before and
after sustained contraction. Muscle biopsies were
examined by light and electron microscopy.
Results: Electrodiagnostic studies revealed pathological
fatigue response in patients compared to controls.
Patients showed statistically significant lower MFCV
(P<0.0001) and higher percent drop in MFCV
following sustained contraction (P<0.001).
Light microscopy examination of patientsf muscle
biopsies revealed a significantly higher percentage of
fiber size variability, increased central nucleation,
increased glycogen and higher percent increase in
fiber type I.
Electron microscopy revealed different
abnormalities. The aggregation of bizarrely-shaped
mitochondria was the most remarkable finding in all
patients, but in none of the controls.
Conclusion: There is definite evidence of neural and
muscular interconnected dysfunction. The
development of fatigue in FMS is significantly
influenced by fiber type composition of the skeletal
muscle and disrupted muscle mitochondria.
Key words: Fibromyalgia, pathophysiology, sympathetic skin response, muscle biopsy, muscle fiber conduction velocity