A 52-year-old man on haemodialysis for six years complains of deep bone pain. Labs show calcium 8.8 mg/dL, phosphate 6.5 mg/dL, intact PTH 950 pg/mL, alkaline phosphatase 480 U/L. Hand radiographs show subperiosteal resorption on the radial aspect of the middle phalanges. Which lesion of renal osteodystrophy does this represent?
- A Osteitis fibrosa cystica ✓
- B Osteomalacia of aluminium toxicity
- C Adynamic bone disease
- D Mixed uraemic osteodystrophy with low turnover
Correct answer: A. Osteitis fibrosa cystica
Explanation
Chronic phosphate retention and reduced calcitriol drive secondary hyperparathyroidism, producing the high-turnover lesion, osteitis fibrosa cystica. Hallmarks are very high PTH, high alkaline phosphatase, subperiosteal resorption classically on the radial side of the index and middle phalangeal cortex, periosteal new bone and brown tumours. Adynamic bone disease shows suppressed PTH and low turnover, and aluminium-related osteomalacia shows low ALP with normal PTH, so both fit poorly here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.