title: Incidence of stool guaiac conversion following extracorporeal shock wave lithotripsy.
abstract: OBJECTIVE
  To study, in a prospective fashion, acute traumatic effects on the gastrointestinal tract of patients treated by extracorporeal shock wave lithotripsy (ESWL).
  
  
  METHODS
  Stool samples from each of 54 patients were tested before and after ESWL for conversion to hemoccult positive. A minimum of one negative pre-ESWL stool guaiac test was required for inclusion into the study. A minimum of two stool guaiac tests were done after ESWL to verify negativity. Patients who converted to a positive hemoccult test after ESWL were then evaluated by colonoscopy for the source of bleeding.
  
  
  RESULTS
  Fifty patients completed the study. A single patient (2.0%) converted to a positive post-ESWL hemoccult test and was evaluated with colonoscopy. This patient was found to have two benign adenomatous polyps in the sigmoid and descending colon after treatment for a left renal pelvis calculus. An additional patient with a slightly positive post-ESWL conversion refused further evaluation. The overall post-ESWL conversion rate to guaiac positive, therefore, was less than 4% (2 of 51 patients).
  
  
  CONCLUSIONS
  There is no evidence of significant trauma or detectable bleeding in the normal gastrointestinal tract caused by ESWL as measured by postprocedure stool guaiac testing. Guaiac testing of the stool after ESWL may unmask pre-existing gastrointestinal disease. Therefore a positive guaiac test after ESWL warrants further evaluation. This study reaffirms that ESWL is a safe, minimally invasive technique for the treatment of urolithiasis, without significant adverse side effects on the gastrointestinal tract.
authors.affiliation: Department of Surgery, Walter Reed Army Medical Center, Washington, D.C. 20307-5001, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Bauer
authors.forename: M J
authors.initials: MJ
authors.lastname: Finger
authors.forename: H B
authors.initials: HB
authors.lastname: Heidenberg
authors.forename: D M
authors.initials: DM
authors.lastname: Preston
authors.forename: F M
authors.initials: FM
authors.lastname: Moses
authors.forename: R A
authors.initials: RA
authors.lastname: Watson
authors.forename: P B
authors.initials: PB
authors.lastname: Irby
mesh_terms: D004064:Digestive System / Q000293:injuries* / Q000378:metabolism; D005243:Feces / Q000737:chemistry*; D006138:Guaiac / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D007202:Indicators and Reagents / Q000032:analysis / Q000378:metabolism*; D008096:Lithotripsy / Q000009:adverse effects*; D011446:Prospective Studies; D014947:Wounds and Injuries / Q000453:epidemiology / Q000209:etiology
chemical_list: D007202:Indicators and Reagents; D006138:Guaiac