Bladder exstrophy: effects on bone age, bone mineral density, growth, and metabolism

Abstract

Bladder exstrophy patients with or without augmentation have not been investigated according to metabolic bone problems, bone ages and growth, and development in details yet. We studied alterations in growth, bone ages, biochemistry of bone, bone mineral densities (BMD) of the forearm, neck of femur and lumbar vertebrae, blood gases, glomerular filtration rates (GFR), and electrolytes of 15 bladder exstrophy patients with augmentation and in those who had no augmentation. In six patients, a sigmoid colon was used for bladder augmentation and one patient underwent a ureterosigmoidostomy. Growth charts of all children were analyzed for determination of the percentiles. The parameters were compared with normal children and a comparison between augmented and nonaugmented patients were made. Growth retardation and decreased bone age were detected in all of the children. Ten patients with bladder exstrophy were below the 10th percentile for height. The mean age/bone age ratio of the patients was 1.59. The mean lumbar and femoral Z scores of the patients were -1.00 and -0.49, respectively. Mean BMD for distal radius was 0.239 g/cm2. Seven patients had a marked BMD decrease, their femoral and/or lumbar Z scores were below -1. Four cases had a pH lower than 7.35. In five patients, a HCO3 level less than 19 mmol/l was detected, four of them had an augmentation. Chloride measurements were slightly increased in six patients and alkaline phosphatase levels in five cases. Reduced GFR values were detected in two patients. There were no significant difference in laboratory values, in percentile height, and weights, in BMDs of femur, vertebra, forearm nor were any differences noted in age/bone age ratios in patients with augmentation when compared with those who had no augmentation. We found varying alteration in bone mineral density and HCO3 levels in patients with bladder exstrophy. Patients with bladder exstrophy, with or without augmentation, may develop serious growth retardation. As much as 45% of them, regardless of presence of augmentation, have an osteopenia or osteoporosis. We found a considerable difference in percentiles of heights as well as bone ages in bladder exstrophy patients when compared with normal population. We recommend close follow up of children with bladder exstrophy for linear growth, development of osteopenia, and bone ages.