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Deficiency of 1,25-dihydroxyvitamin D plays an important role in the pathogenesis of secondary hyperparathyroidism. Adequate replacement of this hormone is required to normalize parathyroid gland function and restore bone homeostasis in patients with advanced renal failure. Controversy exists regarding the best method of administering 1,25-dihydroxyvitamin D. Although initial, uncontrolled clinical trials suggested the superiority of intravenous calcitriol treatment, more recent controlled investigations have shown that different routes (oral versus intravenous), frequency (daily versus intermittent) and dosing (physiologic versus pharmacologic) of calcitriol administration are equivalent. Overall, the response to calcitriol treatment depends more on the severity of secondary hyperparathyroidism and the presence of confounding variables, such as hyperphosphatemia and acquired abnormalities of parathyroid cell function, than on the method of calcitriol administration.

Recent studies of the incidence of acute kidney injury (AKI) are largely based on estimated baseline serum creatinine values. The aim of this study was to more accurately determine the incidence of AKI using the RIFLE criteria for intensive care unit (ICU) patients of a whole population.All adult patients admitted to the ICUs of Landspitali - The National University Hospital of Iceland in 2007 (n = 1026) were studied with meticulous search for baseline creatinine. The underlying risk factors and contributing causes for AKI were defined, and survival and ratio of end-stage renal failure evaluated.A measured baseline creatinine value was found for all but two patients with AKI. The incidence of AKI according to RIFLE criteria was 21.7% [95% confidence interval (CI): 19.0-24.1%], with 7.1% (95 CI: 5.6-8.9%), 6.8% (95 CI: 5.3-8.5%) and 7.8% (95 CI: 6.2-9.6%) in the risk, injury and failure subgroups. Using estimated baseline creatinine overestimated the incidence of AKI by 3.5%. The sensitivity and specificity of the RIFLE criteria using estimated baseline creatinine were 76% and 95%. Renal replacement therapy was required for 17% of the AKI patients. One year survival of AKI patients was 51%, but only 2.5% of patients surviving 90 days required chronic renal replacement therapy.The incidence of AKI in the ICU was lower than previously published, perhaps due to overestimation of AKI using estimated baseline creatinine or bias from tertiary referrals. AKI patients have high mortality, but the survivors have a low incidence of end-stage renal failure.

Continuous ambulatory peritoneal dialysis (CAPD) is now a recognised treatment for end stage renal disease. An estimated number of 27.000 patients was being treated by CAPD world-wide in the year 1985. The most important complication is infection, peritonitis. The CAPD program started in Iceland in April 1985 at the dialysis department of the National University Hospital. The aim of this study was to estimate the incidence of infection associated with peritoneal dialysis during the first five years. All positive cultures of peritoneal dialysates from the Department of Bacteriology, and the hospital records of patients on CAPD, during the time period 12.04.1985 to 12.04.1990, were studied retrospectively. CAPD was considered started as soon as the peritoneal catheter had been inserted. Peritonitis was considered to be present when the white blood cell count was100/ul or there were clinical signs of infection together with a positive culture from the dialysate. During the study period 27 patients were treated by CAPD for 609.6 treatment months. Peritonitis was diagnosed 83 times in 18 of these patients, giving an incidence of 1.63/treatment year. The most common cause was Staphylococcus aureus, which was isolated 35 times (42%). Other causative organisms were: 17 coagulase negative staphylococci (21%), three Gram negative rods (4%), one yeasts and three mixed cultures. In 12 (14%) of the peritonitis episodes, no organisms were isolated. Admission to hospital was considered necessary in 74% of the episodes. One patient died of peritonitis. Studies have demonstrated various infection rates (0.23-6.3 infections/year), but has usually been between 0.8 and 1.2 infections/year. It is of interest to note that the most common causative organism in this study was S. aureus, as opposed to coagulase negative staphylococci, that have normally been the most prevalent. S. aureus usually causes tunnel infections, that are difficult to clear, without removing the catheter. This study demonstrates an above average prevalence of infection, which should prompt a reevaluation of the current management protocols.

In renal failure, several factors lead to parathyroid gland overactivity, manifested by hypersecretion of parathyroid hormnone (PTH) and glanudal hyperplasia eventually leading to monoclonal expansion of glandular cells in severe cases. Main factors contributing to this secondary hyperparathyoidism are increased end-organ resistance to PTH, low serum calcium and high serum phosphate concentrations and decreased production of 1,25-dihydroxyvitamin D3 by the kidneys. Treatment is directed towards correction of these underlying disturbances in meneral metabolism, however, such maneuvers are not always successful in controlling parathyroid gland activity. Functional disturbances within the parathyroid glands e.g., decrements in vitamin D or calcium sensing receptor number or function and/or increased cell mass have been implicated in therapeutic resistance. This article discusses the role of such functional derangements and details the results of a recent study demonstrating the importance of gland mass in this context.

Comparison of treatments for mild secondary hyperparathyroidism in hemodialysis patients.In the management of patients with mild secondary hyperparathyroidism, it is not known whether calcium supplementation alone is sufficient to correct abnormalities in bone and mineral metabolism or if calcitriol is needed in either physiologic oral or intravenous pharmacologic doses.This was a 40-week prospective nonmasked trial of 52 patients [parathyroid hormone (PTH) 150 to 600 pg/mL] who were randomized to receive escalating doses of either calcium carbonate (CaCO3) alone (calcium group, N = 11), daily oral calcitriol (oral group, N = 20), or intermittent intravenous calcitriol (IV group, N = 21). The groups were compared with regard to changes in serum intact PTH, serum bone-specific alkaline phosphatase (BAP), incidence of hypercalcemia (10.5 mg/dL), and hyperphosphatemia (6.5 mg/dL).PTH levels decreased in all groups (P0.01, paired t-test). In the calcium group, PTH (mean +/- SEM) decreased from 325 +/- 46.2 to 160 +/- 44.5 pg/mL. In the oral group, it decreased from 265 +/- 26.4 to 125 +/- 23.7 pg/mL, and in the IV group, it decreased from 240 +/- 27.7 to 65 +/- 10.0 pg/mL. Upon analysis of covariance, controlling for the initial PTH level, we found no differences in the PTH response between the groups (P0.10). In contrast, the BAP concentration increased from 20.7 +/- 7.6 to 27.5 +/- 7.0 microg/L in the calcium group (P = 0.17), decreased from 20. 6 +/- 3.9 to 17.8 +/- 4.5 microg/L in the oral group (P = 0.26), and from 19.1 +/- 2.6 to 10.6 +/- 1.1 microg/L in the IV group (P = 0. 007). Serum calcium increased significantly in all groups from 8.4 +/- 0.25 to 9.0 +/- 0.28, 8.5 +/- 0.16 to 9.2 +/- 0.27, and 8.7 +/- 0.16 to 9.4 +/- 0.18 mg/dL in the calcium, oral, and IV groups, respectively (P = NS difference between groups). Serum phosphorus was significantly lower in the calcium group throughout the study (P = 0.02). Hypercalcemic episodes were 2.0 +/- 0.8, 3.0 +/- 0.6, and 3. 4 +/- 0.6 per patient-year (P0.10), and hyperphosphatemic episodes were 0.9 +/- 0.56, 4.2 +/- 0.79 and 4.9 +/- 0.84 in the calcium, oral, and IV groups, respectively (P0.01).In mild secondary hyperparathyroidism, all three strategies are effective. High-dose CaCO3 alone may be sufficient to control PTH with a favorable side-effect profile, but calcitriol appears to have additional suppressive effects on bone that are greater following the intravenous route of administration and may increase the risk of adynamic bone disease.