Compared effects of calcium and sodium polystyrene sulfonate on mineral and bone metabolism and volume overload in pre-dialysis patients with hyperkalemia.

BACKGROUND: Hyperkalemia is prevalent in end-stage renal disease patients, being involved in life-threatening arrhythmias. Although polystyrene sulfonate (PS) is commonly used for the treatment of hyperkalemia, direct comparison of effects between calcium and sodium PS (CPS and SPS) on mineral and bone metabolism has not yet been studied. METHODS: In a randomized and crossover design, 20 pre-dialysis patients with hyperkalemia (>5 mmol/l) received either oral CPS or SPS therapy for 4 weeks. RESULTS: After 4-week treatments, there was no significant difference of changes in serum potassium (K) from the baseline (ΔK) between the two groups. However, SPS significantly decreased serum calcium (Ca) and magnesium (Mg) and increased intact parathyroid hormone (iPTH) values, whereas CPS reduced iPTH. ΔiPTH was inversely correlated with ΔCa and ΔMg (r = -0.53 and r = -0.50, respectively). Furthermore, sodium (Na) and atrial natriuretic peptide (ANP) levels were significantly elevated in patients with SPS, but not with CPS, whereas ΔNa and ΔANP were significantly correlated with each other in all the patients. We also found that ΔNa and Δ(Na to chloride ratio) were positively correlated with ΔHCO3-. In artificial colon fluid, CPS increased Ca and decreased Na. Furthermore, SPS greatly reduced K, Mg, and NH3. CONCLUSION: Compared with SPS, CPS may be safer for the treatment of hyperkalemia in pre-dialysis patients, because it did not induce hyperparathyroidism or volume overload.

First reported case of collagenofibrotic glomerulopathy with a full-house pattern of immune deposits.

Collagenofibrotic glomerulopathy is a very rare glomerular disease characterized by the deposition of Type III collagen fibrils within the subendothelial and mesangial areas, and by elevated serum levels of pro-collagen Type III peptide. We reported here an elderly patient representing the first case of collagenofibrotic glomerulopathy with a "full-house" pattern of glomerular immunoglobulin and complement deposits by immunofluorescence. A 79-year-old Japanese woman was admitted to our hospital for clinical examinations of leg edema. A renal biopsy specimen showed a remarkable enlargement of the glomerular tufts due to the deposition of periodic acid-Schiff- and Masson's trichrome-positive material. All three immunoglobulins, complements, and light chains were detected in the subendothelial space and capillary walls of the glomeruli. Electron microscopy of tannic acid staining showed spiraled and frayed fibers in the subendothelial areas, which were positive for Type III collagen staining. Serum levels of pro-collagen Type III peptide were increased. Therefore, even in cases where the renal biopsy sample displays a "full-house" immunofluorescence pattern of glomerulopathy, as in systemic lupus erythematosus, we may not always rule out the diagnosis of collagenofibrotic glomerulopathy.