A 66-year-old woman on long-term hemodialysis has a serum PTH of 45 pg/mL (normal 15 to 65). Bone biopsy shows reduced bone turnover, thin osteoid seams, and few osteoblasts and osteoclasts. She has been receiving large doses of calcium based phosphate binders and active vitamin D analogues. The diagnosis is:
- A Osteitis fibrosa cystica
- B Adynamic bone disease ✓
- C Mixed uraemic osteodystrophy
- D Beta-2 microglobulin amyloid arthropathy
Correct answer: B. Adynamic bone disease
Explanation
Adynamic bone disease is the low-turnover lesion of renal osteodystrophy, driven by over-suppression of PTH, commonly from calcium containing binders and active vitamin D therapy. Biopsy shows paucity of cells and thin osteoid seams. Osteitis fibrosa cystica is the high-turnover lesion with woven bone and marrow fibrosis from severe hyperparathyroidism, so the suppressed PTH of 45 pg/mL in dialysis kills option A. It predisposes to fracture and vascular calcification and is managed by reducing suppressive therapy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.