Chronic Kidney Disease-mineral Bone Disorder and Active Vitamin D Analogs for Treating Severe Hyperparathyroidism in Children Receiving Chronic Peritoneal Dialysis

PURPOSE: The aims of this study were to assess the clinical and laboratory profiles of chronic kidney disease-mineral bone disorder (CKD-MBD) and to assess the effects of treatment of active vitamin D analogs on severe hyperparathyroidism (SHPT) in pediatric patients on chronic peritoneal dialysis. METHODS: This is a retrospective study included 53 patients who had been undergoing dialysis for more than 1 year, between January 2003 and December 2012. RESULTS: Even after treatment with phosphate binders and active vitamin D analogs, the mean+/-standard deviation of the percentage of time during peritoneal dialysis that the patients' serum concentrations of phosphorus, corrected total calcium, and parathyroid hormone (PTH) fell within the Kidney Disease Outcomes Quality Initiative recommended ranges was 25.06+/-17.47%, 53.30+/-23.03%, and 11.52+/- 9.51%, respectively. Clinical symptoms or radiological signs of CKD-MBD were observed in 10 patients (18.9%). There were significant differences in percentage of time that the serum intact PTH concentration was outside of the recommended range between patients with and without symptoms or signs of CKD-MBD (below recommended range, 11.74+/-7.37% vs. 40.77+/-25.39%, P<0.001; above the recommended range, 63.79+/-27.86% vs. 37.09+/-27.76%, P=0.022). Of the 25 patients with SHPT, high-dose alfacalcidol treatment was required in 13 patients that controlled SHPT in 7 of these patients, without marked complications. CONCLUSION: Despite our efforts to manage CKD-MBD, patients' met the recommended ranges from relevant guidelines at a low frequency. The treatment of high-dose active vitamin D analogs was required in about half of the patients with SHPT and effective in about half of them.

Disorders of Potassium Metabolism

Hypokalemia usually reflects total body potassium deficiency, but less commonly results from transcellular potassium redistribution with normal body potassium stores. The differential diagnosis of hypokalemia includes pseudohypokalemia, cellular potassium redistribution, inadequate potassium intake, excessive cutaneous or gastrointestinal potassium loss, and renal potassium wasting. To discriminate excessive renal from extrarenal potassium losses as a cause for hypokalemia, urine potassium concentration or TTKG should be measured. Decreased values are indicative of extrarenal losses or inadequate intake. In contrast, excessive renal potassium losses are expected with increased values. Renal potassium wasting with normal or low blood pressure suggests hypokalemia associated with acidosis, vomiting, tubular disorders or increased renal potassium secretion. In hypokalemia associated with hypertension, plasam renin and aldosterone should be measured to differentiated among hyperreninemic hyperaldosteronism, primary hyperaldosteronism, and mineralocorticoid excess other than aldosterone or target organ activation. Hypokalemia may manifest as weakness, seizure, myalgia, rhabdomyolysis, constipation, ileus, arrhythmia, paresthesias, etc. Therapy for hypokalemia consists of treatment of underlying disease and potassium supplementation. The evaluation of hyperkalemia is also a multistep process. The differential diagnosis of hyperkalemia includes pseudohypokalemia, redistribution, and true hyperkalemia. True hyperkalemia associated with decreased glomerular filtration rate is associated with renal failure or increased body potassium contents. When glomerular filtration rate is above 15 mL/min/1.73m2, plasma renin and aldosterone must be measured to differentiate hyporeninemic hypoaldosteronism, primary aldosteronism, disturbance of aldosterone action or target organ dysfunction. Hyperkalemia can cause arrhythmia, paresthesias, fatigue, etc. Therapy for hyperkalemia consists of administration of calcium gluconate, insulin, beta2 agonist, bicarbonate, furosemide, resin and dialysis. Potassium intake must be restricted and associated drugs should be withdrawn.

Treatment of chronic kidney disease in children / 소아과

The treatment of pediatric patients with chronic renal disease comprises management of nutritional imbalance, fluid, electrolyte, and acid-base disturbances, mineral bone disease, anemia, hypertension, and growth retardation. The treatment also includes administration of appropriate renal replacement therapy, if required. Adequate dietary intake of carbohydrates, fats, and proteins and caloric intake must be encouraged in such patients to ensure proper growth and development. In addition, fluid, electrolyte, and acid-base status must be regularly monitored and should be well maintained. Serum calcium, phosphorus, and parathyroid hormone levels must be maintained at their target range, which are determined on the basis of the glomerular filtration rate, to avoid the development of mineral bone disease. This can be achieved by using phosphorus binders and vitamin D analogues. An erythropoiesis-stimulating agent must be administered along with iron supplementation to maintain the hemoglobin level of the patients between 11-12 g/dL. Hypertension must be controlled with adequate water and sodium balance and appropriate antihypertensive agents. Administration of recombinant human growth hormone is recommended to improve the final adult heights.

Current Status of Children on Peritoneal Dialysis in Korea: A Cross-Sectional Multicenter Study

PURPOSE: Peritoneal dialysis (PD) is the major form of dialysis in use for infants and children with end-stage renal disease (ESRD). The aim of this study was to gain insight into the current status of children on PD in Korea. METHODS: In May 2008, questionnaires were sent to the pediatric nephrologists via e-mail. Four centers replied and those data were reviewed. RESULTS: A total of 103 patients were included in this study. Male to female ratio was 1.6:1. Mean age was 11.5+/-4.9 years (0-19 years). Primary renal diseases diagnosed were as follows: primary glomerular disease (34%), chronic pyelonephritis-reflux nephropathy (14.6%), systemic disease (9.7%), renal hypoplasia/dysplasia (8.7%), heredofamilial disease (6.8%), vascular disease (3.9%), drug-induced nephropathy (1.0%), and unknown (12.6%). PD modalities were as follows: CAPD (42.7%), CCPD (27.2%), NIPD (11.7%), and Hybrid (18.4%). Weekly total Kt/V was 2.1+/-0.7 (0.3- 4.1). Results of peritoneal equilibrium test were as follows: low 36.8%, low average 31.6%, high average 19.7%, and high 11.8%. Z-score for weight was -1.00+/-1.20 (-4.54~+2.50). Z-score for height was -1.55+/-1.65 (-9.42~+1.87). Growth hormone was administered in 24.3% of patients. Anti-hypertensive drugs were administered in 64.0% of patients. Laboratory findings were as follows: hemoglobin 10.5+/-1.4 g/dL, calcium 9.7+/-0.7 mg/dL, phosphorus 5.4+/-1.4 mg/dL, and parathyroid hormone 324.2+/-342.8 pg/mL. CONCLUSION: Primary glomerular disease was the most common cause of ESRD. CAPD was the most prevalent PD modality. Low and low average peritoneal transport type were common. Growth disturbance were noted in many patients. Some patients had hypertension even with anti- hypertensive drugs. Calcium-phosphorus levels were maintained adequately, but many patients had secondary hyperparathyroidism.

The clinical manifestations, the short- and long-term outcomes of Bartter syndrome / 소아과

PURPOSE: Bartter syndrome is a renal tubular defect in electrolyte transport characterized by hypokalemia, metabolic alkalosis and other clinical signs and symptoms. The aims of this study were to analyze the clinical manifestations and the short- and long-term outcomes of Bartter syndrome. METHODS: We retrospectively reviewed clinical history, laboratory finding of blood and urine, renal ultrasonography, and hearing tests of five patients who were diagnosed and managed with Bartter syndrome at Asan Medical Center from April 1992 to May 2007. We also evaluated height and body weight periodically after institution of therapy. RESULTS: All patients had poor oral intake, failure to thrive and polyuria. Three of them had maternal history of polyhydramnios and premature delivery. The mean age at diagnosis was 11.8 months. All children presented with hypokalemia, metabolic alkalosis, hyperreninemia. Their blood pressures were normal. One patient had nephrocalcinosis on renal ultrasonography and all of them had normal result in hearing tests. After treatment with indomethacin or other prostaglandin inhibitors and potassium supplementation, their clinical features improved with catch-up growth and improvement in the development during long-term follow-up. CONCLUSION: We emphasize that early diagnosis and proper treatment in patient with Bartter syndrome are related to better prognosis.

A Case of Renal Osteodystrophy with Severe Bone Deformity

With the advent of hemodialysis, the success of renal transplants in the 1960s and the wide use of continuous ambulatory peritoneal dialysis at the end of the 1970s, children with renal failure now enjoy an extended life span. As a result, several children experience renal osteodystrophy and growth retardation. Renal osteodystrophy is induced by phosphorus retention, hypocalcemia, low vitamin D levels and hyperparathyroidism. The pharmacologic interventions are used to prevent bone deformities and to normalize growth velocity. But surgical intervention is required sometimes when osteodystrophy is severe and poorly controlled. We report an eight-year-old boy with chronic renal failure who developed severe bone deformities and needed osteotomy.