Renal osteodystrophy is a bone pathology, characterized by defective mineralization, that results from renal disease. renal - refers to kidney, osteo - refers to bone, and dystrophy - means degenerative disorder (like dystrophy in muscular dystrophy).

There are different forms of renal osteodystrophy. Renal osteodystrophy that is characterized by high bone turnover, and renal osteodystrophy that is characterized by low bone turnover.

Signs and symptoms

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• Silent (no symptoms).
• Bone pain.
• Joint pain.
• Bone deformation.
• Fractures.

Diagnosis

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Usually diagnosed after treatment for end-stage renal disease (ESRD) begins.

• Blood tests - calcium (is decreased), phosphate (is elevated), calcitriol (vitamin D) (is decreased), PTH (is elevated).
• Bone biopsy (bone has abnormal structure).

Can be recognized on X-ray (but may be difficult to differentiate from other conditions). Features on X-ray:

• Calcification of cartilage (chondrocalcinosis) - typically at the knees and pubic symphysis.
• Bone loss - "patchy" appearance (osteopenia)
• Fractures

Pathogenesis

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Renal osteodystrophy results from an abnormally elevated serum phosphate (hyperphosphatemia) and low serum calcium (hypocalcemia), both of which are due to decreased excretion/no excretion of phosphate by the damaged kidney, low vitamin D levels and/or tertiary hyperparathyroidism (a dysfunction of the parathyroid gland due to constant stimulation).

Differential diagnosis

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• osteoporosis
• osteopenia
• osteomalacia
• hyperparathyroidism
• multiple myeloma
• soft tissue calcification including collagen-vascular disease
• hydroxyapatite crystal deposition disease
• hypervitaminosis

Treatment

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• calcium supplementation
• dietary phosphate restriction
• vitamin D
• phosphate binders calcium carbonate (Tums), calcium acetate (PhosLo), sevelamer hydrochloride (Renagel), or lanthanum carbonate (Fosrenol)
• cinacalcet - a calcimimetic
• frequent hemodialysis (five times a week) is thought to be of benefit.
• renal transplantation

Prognosis

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Recovery from renal osteodystrophy has been observed post renal transplantation. Renal osteodystrophy is a chronic (persistent) condition with a conventional hemodialysis schedule.

References

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1. Bonomini V, Mioli V, Albertazzi A, Scolari P. Daily-dialysis programme: indications and results. Nephrol Dial Transplant. 1998 Nov;13(11):2774-7; discussion 2777-8. PMID 9829478 Full Text
2. Ibid.

External links

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• Osteomalacia and Renal Osteodystrophy - emedicine.com
• Renal Osteodystrophy - NKUDIC, NIH
• Renal osteodystrophy - wrongdiagnosis.com
• Symptoms of renal osteodystrophy

Organ failure | Nephrology