The functional response to furosemide in a case of de Toni-Debre-Fanconi disease

The case of a 13-year-old boy with the advanced clinical picture of the idiopathic DeToni-Debré-Fanconi syndrome is described, on whom acute studies of proximal tubular functions and of the effect of furosemide thereon were performed. Sodium bicarbonate loading corrected the hyperchloremic acidosis, but induced an increase of urinary bicarbonate loss of over 20% of the filtered amount. Furosemide corrected bicarbonate reabsorption in spite of the presence of metabolic alkalosis. The urinary excretion of alpha-amino nitrogen, glucose, and phosphates decreased and tubular reabsorption of the two latter increased under furosemide. On a chronic treatment with furosemide and dietary sodium chloride restriction, correction of hyperchloremic acidosis, hypophosphatemia and rickets was achieved.