summary Renal Osteodystrophy is a form of metabolic bone disease seen in patients with chronic renal insufficiency characterized by bone mineralization deficiency due to electrolyte and endocrine abnormalities. Patients present with osteomalacia, osteonecrosis and pathologic fractures. Diagnosis is made based on a thorough evaluation of serum labs, clinical features, and radiographic findings. Treatment involves medical management to resolve the etiology of the underlying renal condition. Etiology Pathophysiology hypocalcemia due to the inability of the damaged kidney to convert vitamin D3 to calcitrol (the active form) because of phosphate retention (hyperphosphatemia) hyperparathyroidism and secondary hyperphosphatemia caused by hypocalcemia and lack of phosphate excretion by damaged kidney uremia related phosphate retention is a key pathological step Associated conditions orthopaedic manifestations osteomalacia (adults) and growth retardation (children) AVN tendinitis and tendon rupture carpal tunnel syndrome login to view 1 more bullet pathologic fracture login to view 1 more bullet osteomyelitis and septic arthritis Classification Two different forms: High-turnover renal bone disease (high PTH disease) chronically elevated phosphate leads to secondary hyperparathyroidism login to view 4 more bullets associated lab values login to view 1 more bullet Low turnover renal bone disease (normal PTH disease) characterized by lack of secondary hyperparathyroidism normal levels of PTH with characteristic bone lesions marked by low levels of bone formation excess deposition of aluminium into bone affects bone mineralization login to view 3 more bullets Presentation Symptom weakness bone pain pathological fracture commonest complication skeletal deformity symptoms of hypocalcemia abdominal pain muscle cramps dyspnea convulsions/seizures mental status changes Physical exam provocative tests for tetany Trousseau's Sign login to view 1 more bullet Chvostek's Sign login to view 1 more bullet Imaging Radiographs findings Looser's zones brown tumor osteosclerosis login to view 2 more bullets widened growth plate and zone of provisional calcification (children) varus deformity of the femurs (children) fracture soft-tissue calcification osteopenia CT osseous resorption Evaluation Histology thinned trabeculae amyloid stains pink on Congo red stain Labs decreased serum calcium increased serum phos increased PTH Treatment Nonoperative treat underlying renal condition or relieve urologic obstruction