title: Clinical relevance of the nutcracker esophagus: suggested revision of criteria for diagnosis.
abstract: BACKGROUND
  Nutcracker esophagus (NE) is a manometric finding defined by peristaltic contractions with a mean distal esophageal amplitude (DEA) >180 mm Hg. This threshold has been selected as it exceeds the average DEA in healthy volunteers by 2 SDs. Since its introduction the clinical significance of this finding has been challenged, as many patients with NE are asymptomatic.
  
  
  OBJECTIVE
  To evaluate whether defining NE based on a different DEA threshold would be clinically more meaningful.
  
  
  METHODS
  Retrospective review of prospectively collected manometry data between October 2001 and December 2003. Using previously published normal DEA values (mean and SD) patients with NE were stratified into 3 groups: group A (2 to 3 SD above mean): DEA 180 to 220 mm Hg; group B (3 to 4 SD above mean): DEA 220 to 260 mm Hg; and group C (>4 SD above mean): DEA >260 mm Hg. Symptoms, esophageal acid exposure, bolus transit data, and lower esophageal sphincter data were reviewed.
  
  
  RESULTS
  The stratification of 56 NE patients into groups A, B, and C were 31, 16, and 9, respectively. The proportion of patients presenting with chest pain increased from 23% in group A to 69% in group B and 100% in group C. Patients in group C had significantly (P<0.05) higher mean lower esophageal sphincter pressure, shorter bolus transit time, and lower frequency of abnormal reflux.
  
  
  CONCLUSIONS
  A revised definition of NE to include patients with a DEA >260 mm Hg, and possibly those with >220 may have greater clinical relevance.
authors.affiliation: Digestive Diseases Center, Medical University of South Carolina, Charleston, SC 29425, USA. agrawala@musc.edu
authors.forename: Amit
authors.initials: A
authors.lastname: Agrawal
authors.forename: Amine
authors.initials: A
authors.lastname: Hila
authors.forename: Radu
authors.initials: R
authors.lastname: Tutuian
authors.forename: Inder
authors.initials: I
authors.lastname: Mainie
authors.forename: Donald O
authors.initials: DO
authors.lastname: Castell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002637:Chest Pain / Q000150:complications; D003679:Deglutition / Q000502:physiology; D019160:Endosonography; D015154:Esophageal Motility Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D004947:Esophagus / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000473:pathology / Q000503:physiopathology; D010528:Peristalsis / Q000502:physiology; D010992:Plethysmography, Impedance / Q000379:methods; D012016:Reference Values; D012189:Retrospective Studies