title: The diagnostic value of hyperammonaemia induced by the non-ischaemic forearm exercise test.
abstract: OBJECTIVE
  The non-ischaemic forearm exercise test (NIFET) is used as a diagnostic tool for the screening of patients with exercise intolerance and for the diagnosis of various metabolic muscle disorders. The production of lactate and ammonia are generally analysed to guide the diagnosis. The aim of this retrospective study was to determine the level of ammonia rise, which can be suggestive of a muscle disease.
  
  
  METHODS
  This retrospective study involved 1440 patients who underwent NIFET. The clinical files of the patients with hyperammonaemia were methodically studied. Normal values were derived from 60 healthy controls.
  
  
  RESULTS
  110 patients with hyperammonaemia were detected. They were classified as either having mild (between 94 and 141 µmol/L) or severe (more than 141 µmol/L) hyperammonaemia. Their diagnosis was studied with respect to the increase in lactate induced by the NIFET.
  
  
  CONCLUSIONS
  Severe postexercise hyperammonaemia, even in the presence of a normal lactate response, is strongly suggestive of a muscle glycogen storage disease. Mild hyperammonaemia in the absence of other abnormalities is most likely non-specific and not indicative of a muscle disease.
authors.affiliation: Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Jean-Yves
authors.identifier: http://orcid.org/0000-0003-0045-7505
authors.initials: JY
authors.lastname: Hogrel
authors.affiliation: Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Jorien B E
authors.initials: JBE
authors.lastname: Janssen
authors.affiliation: Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ledoux
authors.affiliation: Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Gwenn
authors.initials: G
authors.lastname: Ollivier
authors.affiliation: Paris-Est Neuromuscular Center, Institute of Myology, Pitié-Salpêtrière Hospital, Assistance Publique Hôpitaux de Paris, Paris, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Béhin
authors.affiliation: Paris-Est Neuromuscular Center, Institute of Myology, Pitié-Salpêtrière Hospital, Assistance Publique Hôpitaux de Paris, Paris, France.
authors.forename: Tanya
authors.initials: T
authors.lastname: Stojkovic
authors.affiliation: Paris-Est Neuromuscular Center, Institute of Myology, Pitié-Salpêtrière Hospital, Assistance Publique Hôpitaux de Paris, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Eymard
authors.affiliation: Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Nicol C
authors.initials: NC
authors.lastname: Voermans
authors.affiliation: Paris-Est Neuromuscular Center, Institute of Myology, Pitié-Salpêtrière Hospital, Assistance Publique Hôpitaux de Paris, Paris, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Laforet
mesh_terms: D000328:Adult; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005542:Forearm; D006008:Glycogen Storage Disease / Q000175:diagnosis*; D018737:Hand Strength; D006801:Humans; D022124:Hyperammonemia / Q000209:etiology*; D008297:Male; D009135:Muscular Diseases / Q000175:diagnosis*; D012189:Retrospective Studies
keywords: METABOLISM; MUSCLE; neuromuscular