title: The diagnostic yield of the nerve-muscle skin biopsy in paediatric neurology practice. The Montreal Children's Hospital Neuromuscular Group.
abstract: OBJECTIVE
  To determine the diagnostic yield of the nerve-muscle-skin (NMS) biopsy in paediatric neurology practice.
  
  
  METHODS
  A consecutive series of 98 paediatric NMS biopsies done 1989-1994 retrospectively reviewed in the context of pre-biopsy clinical and laboratory parameters. Bivariate associations based on chi-square test. Unconfounded associations between pre-biopsy variables and positive diagnostic yield (PDY) assessed by multiple logistic regression.
  
  
  RESULTS
  Fifty seven out of 98 patients central (global delay, seizures, abnormal CNS imaging) process; 41/98 patients peripheral (motor delay, weakness) process, electromyography-nerve conduction studies (EMG-NCS) 87/98 cases; abnormal 43/87. Positive diagnostic yield (PDY) in 42/98 (43%) biopsies. Statistically significant bivariate associations between PDY and pre-biopsy; age, presenting symptom, developmental delay, weakness, reflexes, CPK, lactate, EMG-NCS and process. Unconfounded associations demonstrated with PDY and age, reflexes and process. The presence of a peripheral process or an abnormal EMG-NCS strongly predictive of PDY: 34/41 (83%) peripheral process cases had PDY, 32/40 (80%) abnormal EMG-NCS cases had PDY, and 29/31 (93.5%) peripheral process and abnormal EMG-NCS cases had PDY. Abnormal EMG-NCS with central process improved PDY to 3/9 (33%) from 4/37 (11%) for normal EMG-NCS.
  
  
  CONCLUSIONS
  NMS biopsy is a valuable diagnostic tool, particularly in the context of a suspected peripheral process or a central processes with an abnormal EMG-NCS.
authors.affiliation: Department of Neurology, McGill University, Montreal, Quebec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Miller
authors.forename: M
authors.initials: M
authors.lastname: Shevell
authors.forename: K
authors.initials: K
authors.lastname: Silver
authors.forename: M
authors.initials: M
authors.lastname: Kramer
mesh_terms: D001706:Biopsy; D002493:Central Nervous System Diseases / Q000175:diagnosis*; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D009132:Muscles / Q000473:pathology*; D009417:Nerve Tissue / Q000473:pathology*; D009462:Neurology / Q000379:methods; D016017:Odds Ratio; D010372:Pediatrics / Q000379:methods; D012189:Retrospective Studies; D012867:Skin / Q000473:pathology*