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Objective: To evaluate 25 hydroxyvitamin D (25-OH-D) deficiency in a cohort ofpredialysis CKD patients and the treatment effect and safety of high dose ergocalciferol supplement in predialysis CKD., Material and Method: Fifty-six predialysis CKD patients who came for a regular visit at a single hospital with calculated glomerular filtration rate < or =60 mL/min/1.73 m2 were screened for 25-OH-D levels. Forty-four patients with 25-OH-D deficiency were recruited into this prospective observational study that examined the effect of high dose oral ergocalciferol supplementation. After eight weeks, 37 patients completed the follow-up and biochemical parameters were reevaluated and analyzed., Results: The mean 25-OH-D level of 56 patients was 25.6 +/- 8 ng/mL. Forty-four (78.5%) patients had 25-OH-D levels less than 30 ng/mL and four (7.1%) had severe deficiency with the level less than 15 ng/mL. High dose ergocalciferol supplement successively increased 25-OH-D levels in 35 (95%) patients. 25-OH-D levels increased significantly from 22 +/- 4.8 to 34.5 +/- 10.8 ng/mL after eight weeks (p < 0.001). During the study period, there were no changes in serum calcium, phosphate, and PTH. There was no other side effect associated with the treatment., Conclusion: 25-OH-D deficiency were found in this cohort of predialysis CKD patients. Ergocalciferol was a safe and effective supplement for the 25-OH-D in predialysis CKD.

Objective: To survey the urinary risk factors associated with recurrent calcium stone and the contribution of renal tubular acidosis to the prevalence of recurrent calcium stone formation in Thai recurrent stone formers., Material and Method: There were 86 consecutive recurrent calcium stone formers. Three-day dietary record, serum biochemical parameters, first morning urine pH, and two 24-hour urine collections were obtainedfrom each subject. Urinary risk factors for calcium stone formation were determined from the average of the 2-day urine collection. Normal controls were 34 subjects matched for aged, sex, and weight, and without a history of renal stone formation., Results: Seven patients (8.1%) were diagnosed as incomplete renal tubular acidosis (iRTA). Among the 79 idiopathic calcium stone formers (ISF), 69.6%, 15.2%, 10.1%, 7.2% and 1.3% of patients were hypocitraturia, hypercalciuria, low urinary volume, hyperuricosuria and hyperoxaluria, respectively. The common combinations of risk factors were hypocitraturia plus low urine output (8.9%) or plus hypercalciuria (7.6%). There were significant differences between ISF and normal controls in urinary oxalate excretion (0.16 +/- 0.01 vs 0.12 +/- 0.01, p < 0.05), urinary calcium/citrate ratio (4.49 +/- 0.50 vs 2.83 +/- 0.34, p < 0.01) and ion activity product for calcium oxalate stone (0. 46 +/- 0.03 vs 0. 33 +/- 0.03, p < 0. 05). Urinary citrate in ISF varied directly with net alkaline absorption (r = 0.34, p < 0.005) and urinary potassium (r = 0.54, p < 0.001). There were significant correlations between urinary calcium excretion and both sodium excretion (r = 0.42, p < 0.001) and urea excretion (r = 0.41, p < 0.001) in ISE There were seven (8.1%) with incomplete renal tubular acidosis. Patients with iRTA tended to have less urinary citrate and higher calcium/citrate ratio than did ISF, but hypercalciuria was uncommon., Conclusions: Hypocitraturia was the most common urinary risk factor found in Thai recurrent idiopathic calcium stone formers followed by hypercalciuria and low urinary volume. Almost one-fourth of the stone formers had multiple risk factors. Hypocitraturia might result from low potassium and low alkaline intake. iRTA was common among recurrent calcium stone formers. Determination of morning urine pH should be a part of the investigations for urinary risk factors to avoid overlooking the diagnosis of iRTA.

Cystine urinary stone is an autosomal recessive hereditary disease, frequently recurring and resisting fragmentation by Shockwave lithotripsy. As cases have never been reported before in Thailand, five cases of renal cystine stones at Ramathibodi Hospital were reported. Two were in the same family. In all cases the stones were removed by open surgery or percutaneous nephrolithotomy. Postoperatively, all the stones were analyzed by infrared spectroscopy for cystine. In two cases, cystine stones were also identified by scanning electron microscopy. Urine was analyzed for cystine by sodium cyanide-nitroprusside test, its concentration by spectrophotometry and cystine crystals were identified by the new crystal induction technique under light microscopy. By high-performance liquid chromatography (HPLC) test, urinary dibasic amino acids (ornithine, lysine, arginine) in these cases were also found to be significantly elevated. Clinical findings, diagnosis, treatment and prevention of cystine stones are reviewed.

Background: Distal renal tubular acidosis (RTA) is a common cause of intractable calcium nephrolithiasis. In adults, the use of potassium citrate (PC) in distal RTA effectively decreases metabolic acidosis and the risk of calcium oxalate stone but it cannot decrease the risk of calcium phosphate stone. However, there is no report for the optimal dose of PC and the risk of calcium stone in distal RTA in children., Objective: To evaluate the optimal dose of PC that minimizes the risk of calcium nephrolithiasis in children with distal RTA., Method: Prospective study, Patients: Children who have distal RTA and were followed-up for 4 months. Patients were studied in a control phase, 1 month of PC 2 mEq/kg/day, 2 months of PC 3 mEq/kg/day and 1 month of PC 4 mEq/kg/day. The urine specimens of 41 normal children were measured for the reference value of the parameters determining the risk of calcium stone., Results: Eight children (mean age of 10 +/- 3.7 years, female : male = 6: 2) with distal RTA were studied during the control phase and after receiving PC 2 mEq/kg/day for I month. Treatment with PC 2 mEq/kg/day was not able to normalize serum bicarbonate and caused no significant change in the urine citrate/creatinine ratio, and activity production of calcium phosphate stone but it caused a significant decrease in the urine calcium/citrate ratio. Although PC 3 mEq/kg/day for I month normalized plasma bicarbonate, only this dose given for 2 months caused a significant increase in the urine citrate/creatinine ratio and urine calcium/ citrate ratio to values that were not different from normal children, while the activity production of calcium phosphate stone did not decrease to normal level. The effect of PC 4 mEq/kg/day was similar to that of 3 mEq/kg/day., Conclusion: Potassium citrate 3 mEq/kg/day for 2 months effectively normalized serum bicarbonate and decreased the risk of calcium oxalate stone but this treatment was theoretically unable to reduce the risk of calcium phosphate stone in children with distal RTA.

Unlabelled: The spectrum and clinical relevance of renal osteodystrophy in Thai dialysis patients are unknown. A study was conducted on the prevalence and clinico-pathological correlation of renal osteodystrophy in chronic dialysis patients who attended Ramathibodi Renal Transplant Clinic between September 1996 and March 1998. All possible volunteers were enrolled irrespective of musculoskeletal symptoms. Fifty six dialysis patients, including 17 (30.4%) CAPD and 39 (69.6%) hemodialysis patients, participated in this study. Serum calcium, phosphate, iPTH, and bone specific alkaline phosphatase were determined. Transiliac crest bone specimens were measured with an average of 30 fields/specimen by a specific computer program for bone histomorphometry (Osteomeasure), and were also studied for dynamic by double tetracycline label. Bone mineral density (BMD) was also determined by DEXA scan. The type of bone pathology was based on Fournier's criteria for renal osteodystrophy. The mean +/- SEM for age was 45.52 +/- 1.74 years, dialysis duration 42.26 +/- 5.54 (range 1-156) months, calcium phosphate product 52.31 +/- 2.77, and iPTH 307.73 +/- 62.04 pg/ml. The following types of renal osteodystrophy were found: adynamic bone 23 (41.1%), hyperparathyroid 16 (28.6%), mixed type 11 (19.6%), mild lesion 3 (5.4%), osteomalacia 2 (3.6%), and osteosclerosis 1 (1.8%) cases. Two cases of aluminum related bone disease were found. The distribution of different bone diseases was not affected by mode of dialysis or vitamin D supplement, but it was affected by dialysis duration. High turnover bone diseases were associated with longer dialysis duration (63.19 +/- 8.9 vs 23 +/- 4.73 months), higher iPTH (541.53 +/- 109.32 vs 87.77 +/- 15.76 pg/ml), and higher bone specific alkaline phosphatase (25.43 +/- 5.04 vs 9.62 +/- 1.34 mg/ml) when compared to low turnover bone diseases, p < 0.05. Intact PTH of greater than 200 pg/ml was a good predictor for high turnover bone diseases (74% sensitivity and 96% specificity). BMD at torch and wards areas varied inversely with dialysis duration (r = -0.3 and r = -0.4, respectively; p < 0.05). Chronic dialysis patients had a greater tendency of bone loss compared to the general Thai population. There was no difference in BMD between CAPD and hemodialysis patients or different types of bone lesions., Conclusion: Significant bone diseases are common among Thai chronic dialysis patients. Adynamic bone disease is the most common bone lesion followed by hyperparathyroid and mixed type. The spectrum of bone diseases is affected mainly by dialysis duration. Intact PTH is a good predictor of high turnover bone disease. Greater bone loss than in the general population is common in our patients and is also accentuated by longer dialysis duration.