Secondary hyperparathyroidism due to Vitamin D deficiency shows:
High-Yield Explanation
Vitamin D deficiency decreases GI absorption of calcium and phosphate, causing hypocalcemia and also hypomagnesemia. Decreased serum calcium will stimulate PTH secretion leading to the elevation of calcium level towards normal along with phosphaturia. Phosphaturia inturn will lead to hypophosphatemia. Ref: Endocrine Physiology : Mosby Physiology Monograph Series, 3rd Edition, Page 101; Ganong's Review of Medical Physiology, 23rd Edition, Chapter 23; The Endocrine System at a Glance By Ben Greenstein, 3rd Edition, Page 117.