PEDIATRIC UROLOGY

Ileal enterocystoplasty and B12 deficiency in pediatric patients
Rosenbaum DH, Cain MP, Kaefer M, Meldrum KK, King SJ, Misseri R, Rink RC
Division of Pediatric Urology, Riley Hospital for Children, Indianapolis, Indiana, USA
J Urol. 2008; 179: 1544-7; discussion 1547-8

• Purpose: Vitamin B12 deficiency is a feared complication of enterocystoplasty but it has never been demonstrated in pediatric patients who have undergone ileal enterocystoplasty. We reviewed our series of more than 500 bladder augmentations in an attempt to define the timing and risk of vitamin B12 deficiency in pediatric patients after bladder augmentation.
• Materials and Methods: From October 2004 to present we obtained serum B12 values in patients who had undergone bladder augmentation at our institution. We looked at patients who had undergone ileal enterocystoplasty and who were 18 years or younger at the time of augmentation. Any B12 value that was obtained while on any form of B12 supplementation was excluded. These criteria resulted in 79 patients with 105 B12 values. B12 values of 200 pg/mL or less were considered “low”, and values between 201 and 300 pg/mL were considered “low-normal”.
• Results: There was a statistically significant correlation between follow-up time and serum B12 (p = 0.0001). The probability of low B12 increased as follow-up time increased (p = 0.007), as did the probability of low-normal B12 (p = 0.005). Starting at 7 years postoperatively 6 of 29 patients (21%) had low B12 values, while 12 of 29 (41%) had low-normal values.
• Conclusions: Pediatric patients who have undergone ileal enterocystoplasty are at risk for development of vitamin B12 deficiency. These patients are at the highest risk beginning at 7 years postoperatively, and the risk increases with time. We recommend an annual serum B12 value in children beginning at 5 years following bladder augmentation.
  
  
• Editorial Comment
  This research project involved the measurement of B12 levels starting in October 2004 on all bladder augmentation patients that had terminal ileum utilized for the bladder augmentation. Eighty-six patients with B12 levels were available for evaluation and 10 of those patients were being treated for B12 deficiency and were excluded. Seventy-nine percent were studied with B12 levels. Seven of 79 patients (9%) had low B12 levels and 29% had low normal levels. The patients with the longest follow up had the lower B12 levels in general. Sixty-two percent of patients who had been followed for longer than 7 years (29 patients), had lower or normal B12 values. The authors suggest that B12 levels be obtained in patients who have had an ileocystoplasty beginning at 5 years postoperatively.
  It is not surprising that if terminal ileum has been “resected” and used as a bladder augmentation that B12 metabolism may be affected. There were only 7 patients who were truly below the lowest limits of normal B12 values in their institution and the authors include a number of patients that have values in the normal range and consider them low normal. There was no megaloblastic anemia in their study and no neurologic deficits, although there study raises the concern that long-term follow up will be necessary and treatment before the megaloblastic anemia or neurologic symptoms occur, would obviously be in the patient’s best interest.

Dr. Brent W. Snow
Division of Urology
University of Utah Health Sci Ctr
Salt Lake City, Utah, USA
E-mail: brent.snow@hsc.utah.edu