title: The role of muscle biopsy in investigating isolated muscle pain.
abstract: OBJECTIVE
  To evaluate the muscle biopsy findings from 240 patients who had isolated muscle pain.
  
  
  METHODS
  Histopathology, immunohistochemistry for dystrophin, dystrophin-related proteins, major histocompatibility complex type I, and biochemical analysis of glycolytic and mitochondrial respiratory chain enzymes were performed on muscle biopsies. An attempt was made to correlate pathologic data and clinical findings (sex, age, quality and distribution of symptoms, serum CK levels, and EMG recording).
  
  
  RESULTS
  We have described five groups of patients based on muscle biopsy findings: 51.6% had heterogeneous myopathic abnormalities; only 19% of them had a specific myopathic picture, i.e., central nuclei myopathy, central core disease, myopathy with tubular aggregates or with trabecular fibers or abnormalities of fiber typing; 20% had signs of respiratory chain dysfunction but only one patient had a probable mitochondrial disease; 7% had a neurogenic pattern; 2.4% had a metabolic myopathy (phosphorylase or phosphofructokinase deficiency); and 19% had normal muscle biopsy. No clear-cut correlation between muscle biopsy and clinical data was observed except for those patients with a metabolic myopathy.
  
  
  CONCLUSIONS
  The probability that a patient complaining only of muscle pain and with a normal neurologic examination has a definite muscle pathology is 2%. Only patients with sole exercise-related muscle pain and sCK seven times higher than the normal value are strongly suspected of having a metabolic myopathy. A rigorous selection of patients is needed before performing a muscle biopsy.
authors.affiliation: Department of Neurological Sciences and Vision, Section of Clinical Neurology, University of Verona, P.le L.A. Scuro 10, 37134 Verona, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Filosto
authors.forename: P
authors.initials: P
authors.lastname: Tonin
authors.forename: G
authors.initials: G
authors.lastname: Vattemi
authors.forename: L
authors.initials: L
authors.lastname: Bertolasi
authors.forename: A
authors.initials: A
authors.lastname: Simonati
authors.forename: N
authors.initials: N
authors.lastname: Rizzuto
authors.forename: G
authors.initials: G
authors.lastname: Tomelleri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000379:methods / Q000706:statistics & numerical data*; D002648:Child; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000453:epidemiology* / Q000473:pathology*; D010146:Pain / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity