Calcipenic and Phosphopenic Osteomalacia

Calcipenic osteomalacia arises primarily from vitamin D deficiency or resistance, or severe calcium malabsorption, resulting in impaired mineralization due to defective intestinal calcium transport and secondary hyperparathyroidism that accelerates bone resorption and hypophosphatemia. Phosphopenic osteomalacia stems from renal phosphate wasting, frequently driven by excess fibroblast growth factor 23 or hereditary tubular defects, which directly impairs hydroxyapatite crystal formation. Both entities manifest with bone pain, proximal muscle weakness, and pseudofractures, but precise differentiation via serum calcium, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, intact parathyroid hormone, and fibroblast growth factor 23 levels is essential to direct targeted replacement or mechanism-specific antineoplastic or biological therapies.