title: Bowel preparation in CT colonography: electrolyte and renal function disturbances in the frail and elderly patient.
abstract: OBJECTIVE
  Elderly patients are at increased risk of biochemical disturbances secondary to cathartic medications. This study investigates the renal function, electrolyte and clinical disturbances associated with CT colonography (CTC) with sodium picosulphate-magnesium citrate (SPS-MC) in a subgroup of frail, elderly patients.
  
  
  METHODS
  Patients aged over 70 years considered at risk of complication during SPS-MC administration by a physician specialised in care of the elderly were included in this retrospective study. Biochemical parameters pre- and post-CTC and the presence of co-morbidities were recorded. Imaging findings and quality of bowel preparation at CTC were graded by consensus by two radiologists.
  
  
  RESULTS
  Of the 72 patients 56% had co-morbidities that caution the use of SPS-MC. No significant changes in serum urea, sodium, potassium or estimated glomerular filtration rate (eGFR) occurred post-CTC (p > 0.10). Serum magnesium increased by 0.11 mmol/L in 14 patients (p = 0.03) without clinical sequelae. Good overall preparation was achieved in 88% of patients, allowing confident identification of signs of colonic neoplasia in 20 patients (27%). A mild increase in serum magnesium but no other significant biochemical disturbance was observed.
  
  
  CONCLUSIONS
  In our group CTC with SPS-MC was safe and effective; however, we advise an alternate preparation be considered in patients with decreased renal function due to decreased magnesium clearance.
authors.affiliation: Department of Radiology, Cork University Hospital, Wilton, Cork, Ireland. mclaughlin.paddy@gmail.com
authors.forename: Patrick
authors.initials: P
authors.lastname: Mc Laughlin
authors.forename: Joseph
authors.initials: J
authors.lastname: Eustace
authors.forename: Sean
authors.initials: S
authors.lastname: Mc Sweeney
authors.forename: Sebastian
authors.initials: S
authors.lastname: Mc Williams
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Regan
authors.forename: Michael
authors.initials: M
authors.lastname: O'Connor
authors.forename: Denis
authors.initials: D
authors.lastname: Kelly
authors.forename: Michael M
authors.initials: MM
authors.lastname: Maher
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002400:Cathartics / Q000009:adverse effects*; D023881:Colonography, Computed Tomographic / Q000009:adverse effects*; D003287:Contrast Media / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007674:Kidney Diseases / Q000139:chemically induced* / Q000175:diagnosis; D008297:Male; D014883:Water-Electrolyte Imbalance / Q000139:chemically induced* / Q000175:diagnosis
chemical_list: D002400:Cathartics; D003287:Contrast Media