Phosphopenic Osteomalacia

Phosphopenic disorders encompass conditions characterized by systemic phosphate wasting or deficiency, driven primarily by renal tubular defects, fibroblast growth factor 23 excess, or impaired gastrointestinal absorption. Key clinical manifestations include osteomalacia, rickets, muscle weakness, and profound fatigue. Diagnostic evaluation requires rigorous assessment of serum phosphate, fractional excretion of filtered phosphate, fibroblast growth factor 23 levels, and 1,25-dihydroxyvitamin D status. Management focuses on targeted etiology-specific therapy, incorporating phosphate supplementation combined with active vitamin D analogs to restore biochemical homeostasis and skeletal integrity while avoiding hypercalciuria and nephrocalcinosis.