In an adult patient presenting with severe nutritional osteomalacia, which of the following laboratory profiles is most characteristic prior to the initiation of definitive treatment?

Explanation:
Nutritional osteomalacia (severe Vitamin D deficiency) leads to decreased intestinal absorption of calcium and phosphate. This hypocalcemia triggers secondary hyperparathyroidism (elevated PTH). The high PTH levels stimulate bone resorption (elevating alkaline phosphatase) and increase renal phosphate excretion, leading to hypophosphatemia. Therefore, the classic profile is low/low-normal calcium, low phosphate, high alkaline phosphatase, and high PTH. Reference: Orthopaedic Basic Science, 4th Edition.