Bone Pathology Database

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2nd image
AP of Pelvis
Chronic renal failure on dialysis. Slow development of masses in both thighs. The Xray of the femur shows massive calcification in the soft tissues as well as osteolysis in the femur. The AP view of the pelvis shows the extent of her calcification in the soft issues.
Chronic renal failure results in secondary and later tertiary hyoparathyroidism.
- early stages of CKD-Mineral and Bone Disorder:
- effects on bone are primarily due to action of parathyroid hormone on osteocyte-osteoblast
lining cell system, which is probably result of decreased phosphate excretion by the kidney;
- w/ decreased phosphate excretion, there is elevation of plasma phosphate & complexing
of calcium & phosphate in bone fluid;
- as result, increasing amounts of PTH hormone are required to move the same amount of calcium from bone in order to maintain the plasma calcium at a constant level;
- due to elevated parathyroid hormone levels, there is increase in number of bone remodelling centers & increase in bone turnover;
- late stages:
- when the glomerular filtration falls below 25% of normal, increased secretion of PTH is no longer able to maintain normal phosphate levels, and the serum phosphate increases;
- mineralization of previously osteomalacic bone then occurs, and osteosclerosis develops; (see ossification of soft tissue);
- end stages:
- diminished ability of kidney to hydroxylate Vitamin D leads to a decrease in circulating levels of 1,25(OH)2D3 & produces decrease in intestinal calcium absorption;
- calcification of osteoid is inhibited owing to deficiency of 1,25(OH)2D3, and owing to metabolic acidosis and other circulating inhibitors of mineralization that occur in uremic state;
- net effect of renal dz on bone:
- is combination of secondary hyperparathyroidism, osteomalacia, and osteosclerosis;
- when bone disease becomes severe, pathologic fractures may occur, esp in ribs, pelvis, and hips;
- uremic pts w/ advanced hyperparathyroidism appear prone to nontraumatic aseptic necrosis of the hips;
- bone pain, frx, and concomitant muscle disease may be the major impediment to rehabilitation in chronic uremia;
The above patient is in a late stage of CKD-Mineral and Bone Disorder.
Treatment The role of surgery is limited. In the early stages parathyroidectomy may limit the decalcification caused by excessive parathyroid hormone. Excision of the calcified masses has only a limited success. The calsification is in normal muscle and other soft tissue and cannot easily be excised
as in this case. Control of renal function by conservative methods, as well as dialysis is necessary Patients on chronic renal dialysis often have CKD-Mineral and Bone Disorder ( renal osteo dystrophy). If the bone stock is normal ( was no period of hyperparathyroidosis) the condition is known as Tumoral Calcinosis.

Record 18