title: Exertional muscle pain in familial Mediterranean fever patients evaluated by MRI and 31P magnetic resonance spectroscopy.
abstract: OBJECTIVE
  To evaluate the effect of physical activity on the structural, morphological, and metabolic characteristics of the gastrocnemius muscle in familial Mediterranean fever (FMF) patients, utilizing quantitative (31)P magnetic resonance spectroscopy (MRS), in order to elucidate the mechanism of their exertional leg pain.
  
  
  METHODS
  Eleven FMF patients suffering from exertional leg pain (eight male, three female; mean age 33 years) and six healthy individuals (three male, three female; mean age 39 years) constituted the control group. All of the participants underwent magnetic resonance imaging (MRI) and non-selective (31)P MRS (3 T) of the leg muscles before and after graded exercise on a treadmill. Phosphocreatine (PCr):inorganic phosphate (Pi), PCr:adenosine triphosphate (ATP) ratios and the intracellular pH of the leg muscles were measured using (31)P MRS.
  
  
  RESULTS
  For both groups, normal muscle mass with no signal alterations was observed on the MRI images after exercise. The normal range of pre- and post- exercise MRS muscle parameters was observed in both groups. However, the intracellular pH post-exercise, was significantly higher (less acidic) in the FMF group compared to the control group [pH (FMF) = 7.03 ± 0.02; pH (control) 7.00 ± 0.02; p < 0.0006].
  
  
  CONCLUSIONS
  The finding of a less prominent, post-exercise acidification of the gastrocnemius muscle in this FMF patient group suggests a forme fruste of glycogenosis. This preliminary observation should be further investigated in a future, larger-scale study.
authors.affiliation: Department of Diagnostic Imaging, The Sheba Medical Center, Tel Hashomer/Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Kushnir
authors.forename: I
authors.initials: I
authors.lastname: Eshed
authors.forename: Y
authors.initials: Y
authors.lastname: Heled
authors.forename: A
authors.initials: A
authors.lastname: Livneh
authors.forename: P
authors.initials: P
authors.lastname: Langevitz
authors.forename: I
authors.initials: I
authors.lastname: Ben Zvi
authors.forename: E
authors.initials: E
authors.lastname: Konen
authors.forename: M
authors.initials: M
authors.lastname: Lidar
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D005080:Exercise Test / Q000379:methods; D010505:Familial Mediterranean Fever / Q000150:complications*; D005260:Female; D006801:Humans; D007866:Leg; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology*; D010146:Pain / Q000209:etiology* / Q000503:physiopathology*; D005082:Physical Exertion