Bone density and skeletal metabolism in patients with orthotopic ileal neobladder.
The interposition of a bowel segment as a bladder substitute into the urinary tract may result in impaired calcium metabolism. We studied 25 male patients (aged 45 to 77 yr) who had undergone a Vescica Ileale Padovana (VIP) reconstruction following cystectomy 29 to 75 mo before. Bone mineral density of the spine and femur was measured by dual x-ray absorptiometry. Blood and 24-h urine samples were analyzed for the main parameters of bone metabolism. Sixteen healthy men were enrolled as a control group. Although blood pH did not differ between patients and control subjects, VIP subjects showed lower levels of plasma HCO3- (P < 0.005) and higher serum chloride (P < 0.001). Bone alkaline phosphatase was higher (P < 0.001), and urine calcium, phosphate, and creatinine levels were lower in VIP patients (P < 0.01, P < 0.01, and P < 0.05, respectively). Bone mineral density at the femoral neck (P < 0.03) and Ward's triangle (P < 0.05) was decreased in VIP patients. When subdivided according to time since operation, patients who had the ileal neobladder implanted for a shorter period of time showed lower blood pH (P < 0.03) and urine calcium (P < 0.05) levels and higher urinary hydroxyproline (P < 0.02). Duration of the ileal neobladder was positively correlated with PTH (r = 0.46, P < 0.03) and blood pH (r = 0.47, P < 0.02). Furthermore, pH values were positively correlated with urine calcium (r = 0.48, P < 0.02). In conclusion, in patients with ileal neobladder, a mild metabolic acidosis is responsible for an increased bone turnover and lower bone mass. Moreover, a decrease over time in the absorption capacity of the ileal pouch might result in calcium malabsorption, which represents an additional risk factor for reduced bone mass in these patients.
Giannini
S
S
Institute of Internal Medicine and National Research Council, Centre for Aging Studies of Padova, Italy.
Nobile
M
M
Sartori
L
L
Aragona
F
F
Ruffato
A
A
Dalle Carbonare
L
L
Ciuffreda
M
M
Liberto
L
L
Artibani
W
W
D'Angelo
A
A
Crepaldi
G
G
Pagano
F
F
D000368:Aged; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism* / Q000652:urine; D016022:Case-Control Studies; D015653:Cystectomy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007082:Ileum / Q000637:transplantation; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D016042:Transplantation, Heterotopic; D001743:Urinary Bladder; D014547:Urinary Diversion / Q000009:adverse effects* / Q000379:methods
D010281:Parathyroid Hormone; D002118:Calcium