Hipofosforemia en unidades de diálisis crónica / Hypophosphatemia in dialysis units

RESUMEN

La hipofosforemia (Hf) se describe raramente en los pacientes en hemodiálisis (HD) crónica. Hemos recogido retrospectivamente los casos de Hf ocurridos durante 3 años en un mismo centro. Revisamos todas las determinaciones de P realizadas (n = 2.201), considerándose Hf una concentración de P plasmático menor de 2,5 mg/dL. Posteriormente, se recogieron los datos clínicos y bioquímicos de cada caso para analizar las causas, síntomas y el tratamiento aplicado. Recogimos 22 episodios de Hf (0,9% del total de mediciones de P) en 11 pacientes sobre un total de 149 enfermos (7,3%) en tratamiento con HD convencional. Separamos dos grupos según presentaran Hf repetida (grupo A, n = 3) o aislada (grupo B, n = 8). Las concentraciones de P y albúmina y la nPCR, fueron menores en el grupo A, mientras que el B presentaba un calcio plasmático significativamente mayor (p 3 mg/dL. Concluimos que la Hf en HD no es tan infrecuente como se suele considerar, pudiendo aparecer de forma mantenida en pacientes con baja ingesta. La disminución aguda de la ingesta manteniendo los ligantes habituales, unida a la administración de antiácidos es la causa más frecuente de Hf esporádica en pacientes con buen control del P, que pueden tener incluso un hiperparatiroidismo secundario

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, ocurring 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: lowprotein diet and alcoholism, Group B: decreased dietary intake due to non-digestive problems (n = 2) or due to digestive problems plus antacids (n = 4), phosphate 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 requiered 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 lowprotein 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