In fibrous osteodystrophy due to an all-meat diet, which mineral pattern is typically observed?

In fibrous osteodystrophy due to an all-meat diet, which mineral pattern is typically observed?

• A. Low calcium, high phosphate, high PTH.
• B. High calcium, high phosphate, high PTH.
• C. Low calcium, low phosphate, low PTH.
• D. Low calcium, high phosphate, low PTH.

Answer: (A)

This reflects disruption of the calcium‑phosphate‑PTH axis. An all‑meat diet is rich in phosphorus but low in calcium, so serum calcium falls. In response, the parathyroid glands release more PTH (secondary hyperparathyroidism). PTH acts to raise calcium levels by increasing bone resorption, increasing renal calcium reabsorption, and boosting vitamin D–mediated intestinal calcium absorption, but the high dietary phosphate keeps phosphate levels elevated. The combination of low calcium, high phosphate, and high PTH drives fibrous osteodystrophy through chronic bone remodeling and fibrous tissue replacement.

This reflects disruption of the calcium‑phosphate‑PTH axis. An all‑meat diet is rich in phosphorus but low in calcium, so serum calcium falls. In response, the parathyroid glands release more PTH (secondary hyperparathyroidism). PTH acts to raise calcium levels by increasing bone resorption, increasing renal calcium reabsorption, and boosting vitamin D–mediated intestinal calcium absorption, but the high dietary phosphate keeps phosphate levels elevated. The combination of low calcium, high phosphate, and high PTH drives fibrous osteodystrophy through chronic bone remodeling and fibrous tissue replacement.