title: False-positive result of a captopril-enhanced radionuclide renogram in a child secondary to dehydration.
abstract: OBJECTIVE
  Renovascular hypertension is an unusual cause of elevated mean arterial pressure in children. When suspected, angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy is usually one of the initial studies done to evaluate patients. The accuracy of this test depends not only on patient selection but also on technical factors involved in performing the study. We report a case of a false-positive angiotensin-converting enzyme inhibitor-enhanced radionuclide renogram in a 5-year-old boy with hypertension.
  
  
  METHODS
  Angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy was performed and the result was interpreted as positive for bilateral renovascular disease. A review of the anesthesia record from the study revealed that the patient was hypotensive. A repeated study with adequate hydration and blood pressure stability was then done.
  
  
  RESULTS
  The result of the second examination was interpreted as normal, without evidence of abnormal renovascular physiology.
  
  
  CONCLUSIONS
  The cause of the initial false-positive result was determined to be dehydration with secondary hypotension. Dehydration, with secondary hypotension, can cause a diminished glomerular filtration rate and mimic bilateral renovascular physiology on angiotensin-converting enzyme inhibitor-enhanced renal scans.
authors.affiliation: Department of Radiology, National Naval Medical Center, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Levey
authors.forename: F V
authors.initials: FV
authors.lastname: Schraml
authors.forename: S H
authors.initials: SH
authors.lastname: Abreu
authors.forename: E D
authors.initials: ED
authors.lastname: Silverman
mesh_terms: D000768:Anesthesia, General; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D001794:Blood Pressure / Q000502:physiology; D002216:Captopril; D002675:Child, Preschool; D003681:Dehydration / Q000150:complications* / Q000503:physiopathology; D003937:Diagnosis, Differential; D004656:Enalapril; D005189:False Positive Reactions; D005440:Fluid Therapy; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007022:Hypotension / Q000209:etiology; D007668:Kidney / Q000000981:diagnostic imaging*; D008297:Male; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D006993:Hypnotics and Sedatives; D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide; D004656:Enalapril; D002216:Captopril