[Hypophosphatemia in dialysis units]

Abstract

Hypophosphatemia (Hf) is infrequently reported in chronic hemodialysis patients. The objective of this report is to describe the incidence, etiology, symptoms and treatment of Hf in a Dialysis Unit (defined as phosphorus < 2.5 mg/dL). In a retrospective study over a period of three years, we identified 22 cases of Hf, occurring on 11 among 149 patients. A two-groups distribution was made: Group A, patients with more than one episode (n = 3, 14 episodes of Hf) and Group B, patients with only one isolated episode of Hf (n = 8, 8 episodes of Hf). Plasma Ca, P, Albumin and nPCR were significant lower in group A (p < 0.05). Only two patients of group B had symptoms. Cases of Hf were: Group A: low-protein diet and alcoholism, Group B: decreased dietary intake due to non-digestive problems (n = 2) or due to digestive problems plus antacids (n = 4), phos-phate binders (n = 1) and dietary phosphorus restriction (n = 1). Three patients had secondary hyperparathyroidism. Treatment consisted on oral supplementarion by diet and changes in oral calcium salts. Intravenous supplementation was required acutely to raise serum P in a patient with auricular fibrilation. Two group A patients who has plasma 1.25 vitamin D < 5 pg/mL received vitamin D, and the third oral supplements of P. In all the cases, Hf resolved with these measures. We concluded that Hf is not so infrequent in hemodialysis. In patients with low-protein diet and low vitamin D concentration, Hf can be sustained. On the other hand, a decreased dietary intake maintaining similar phosphate binder's supplementation is the most frequent cause of occasional and symptomatic Hf, even in patients with secondary hyperparathyroidism.