Background: We investigated the effect of vitamin D deficiency on cardiovas-cular risk profiles in an Asian population with chronic kidney disease (CKD). Methods: A total of 210 participants (62 non-dialysis CKD patients and 148 hemodialysis [HD] patients) were enrolled between December 2009 and February 2010. Vitamin D deficiency was determined using the serum 25- hydroxyvitamin D [25(OH)D] concentration. Blood pressure and arterial stiff ness were measured. Subjects were divided into groups according to 25 (OH)D concentration based on a cut-off of 13.5 ng/mL in non-dialysis CKD patients and 11.3 ng/mL in HD patients. Results: The mean age was 61.7±12.3 years in non-dialysis CKD patients and 57.0±12.7 years in HD patients. In the non-dialysis CKD group, mean esti-mated glomerular filtration rate (eGFR) was 29.7±15.4mL/min/1.73m2. Mean 25(OH)D concentration was 13.6±7.8 ng/mL in non-dialysis CKD patients and 11.3±6.7 ng/mL in HD patients. More than half of the subjects had vitamin D deficiency (67.6% in non-dialysis CKD patients and 80.4% in HD patients). There were no significant differences in systolic blood pressure, pulse press-ure, and arterial stiffness between higher and lower 25(OH)D groups among non-dialysis CKD and HD patients. Multivariate analysis revealed that female sex (odds ratio [OR]: 5.890; 95% confidence interval [CI]: 2.597-13.387; p<0.001) and presence of diabetes (OR: 2.434; 95% CI: 1.103- 5.370; p=0.028) were significantly associated with lower serum 25(OH)D levels in HD patients. Conclusion: The prevalence of vitamin D deficiency was high in both non-dialysis CKD patients and HD patients. Serum 25(OH)D concentration was not a significant factor associated with blood pressure and arterial stiffness among non-dialysis CKD and HD patients.

• Blood pressure
• Cardiovascular risk
• Chronic kidney disease
• 25-Hydroxyvitamin D

Amyotrophic lateral sclerosis (ALS) patients rarely present with either syn-drome of inappropriate antidiuretic hormone secretion or generalized edema. Tolvaptan is a selective vasopressin V2 receptor antagonist that produces effective aquaresis, and its use in ALS patients has not been previously reported. A 50-year-old male ALS patient was admitted be-cause of both generalized edema and dilutional hyponatremia. These manifestations were refractory to conventional diuretics and fluid therapy, but a very brisk diuresis was induced by tolvaptan administration. Edema and hyponatremia were also improved, and the patient was able to be discharged without tolvaptan. In this case report, we postulate how edema and dilutional hyponatremia developed in the patient, and discuss the mechanism of tolvaptan in treating hypervolemic hyponatremia. Further experience is necessary to evaluate the usefulness of tolvaptan in pa-tients with neurological disorders.

• Amyotrophic lateral sclerosis
• Diuresis
• Edema
• Hyponatremia
• Tolvaptan

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of euvolemic hypo-osmotic hyponatremia. There are several etiologies of SIADH including neuroendocrine tumor, pulmonary disease, infection, trauma, and medications. Here, we report a case of SIADH asso-ciated with a schwannoma involving the mediastinum in a 75-year-old woman who presented with nausea, vomiting, and general weakness. Laboratory testing showed hypo-osmolar hyponatremia, with a serum sodium level of 102mmol/L, serum osmolality of 221mOsm/kg, urine osmolality of 382mOsm/ kg, urine sodium of 55 mmol/L, and plasma antidiuretic hormone (ADH) of 4.40 pg/mL. Chest computed tomography identified a 1.5-cm-sized solid enhancing nodule in the right lower paratracheal area. A biopsy specimen was obtai-ned by video-assisted thoracoscopic surgery, which was diagnosed on pat-hology as a schwannoma. The hyponatremia was completely resolved after schwannoma resection and plasma ADH level decreased from 4.40 pg/mL to 0.86 pg/mL. This case highlights the importance of suspecting and iden-tifying the underlying cause of SIADH when faced with refractory or recur-rent hyponatremia, and that on possibility is mediastinal schwannoma

• Hyponatremia
• Syndrome of Inappropriate ADH (SIADH) Secretion
• Mediastinal schwannoma