Prof A. Wiecek Professor of Internal Medicine and Nephrology Head of the Department of Nephrology, Endocrinology and Metabolic Diseases Silesian University School of Medicine Katowice, Poland

 

A 55-years old patient with chronic renal failure due to chronic glomerulonephritis on haemodialysis for 10 years was admitted to the orthopaedic department due to the peritrochanteric fracture of the left femur. During the entire period of renal replacement therapy this patient was uncompliant with respect to a low phosphorus diet and was treated regularly with calcium carbonate (3-6 g per day) and periodically with aluminium hydroxide as phosphate binders. Seven years later severe secondary hyperparathyroidism was diagnosed (iPTH 750 pg/ml), and active vitamin D metabolites were introduced. Repeated measurements of bone mineral density showed a continuous decrease of bone mineralisation.
Twelve months before the fracture occurred, the patient started to complain of pain in the left hip. Radiological examination revealed large periarticular femoral soft tissue calcification and calcification of the vascular wall of the aorta and both iliac arteries. Administration of vitamin D metabolites were suspended and sevelamer with low calcium dialysis fluid (1,25 mmol/l) were introduced. Nevertheless, radiological examination 8 months later showed an enlargement of metastatic calcifications.

Figure 1	Figure 2

After admission to the orthopaedic department, the fractured bone was stabilised with a Wagner revision prosthesis. During the following days, the patient developed hypercalcaemia (total serum calcium 3,2 mmol/l, ionised blood calcium 2,1 mmol/l). Serum phosphorus was elevated (2,1-2,4 mmol/l). Haemodialysis sessions performed daily with low calcium dialysate (1,25 mmol/l) and intravenous bisphosphonates were ineffective to treat the high serum calcium. A month after the incidence, the Wagner revision prosthesis was removed and the fracture fragments were joined surgically with 3 proximal femoral nails.

Question 1

The treatment of hypercalcaemia was continued with oral bisphosphonates for the next 2 months but was not effective (total serum calcium 3.1 mmol/l). In spite of persistent hypercalcaemia, the plasma parathyroid hormone concentration decreased from over 1000 pg/ml to 130 pg/ml. After visualisation of 4 enlarged parathyroid glands, the patient was referred to a surgeon. Successful subtotal parathyreoidectomy was followed by normalisation of serum concentrations of calcium and phosphorus.
Twelve moths later, repeated radiological examination of the left femur revealed nearly complete disappearance of periarticular calcification; however the fracture had still not entirely healed.

Figure 3

Question 2 and 3

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