From the Guidelines
The best next step in management for this patient is to discontinue calcitriol. This 60-year-old woman with end-stage kidney disease on peritoneal dialysis has developed a stress fracture in her right tibia, likely due to renal osteodystrophy. Her laboratory values show elevated phosphorus (5.4 mg/dL) and calcium (10.3 mg/dL) levels, while her parathyroid hormone level is suppressed (26 pg/mL) relative to what would be expected in kidney disease. This pattern suggests adynamic bone disease, a form of renal osteodystrophy characterized by low bone turnover. Calcitriol, a vitamin D analog, increases calcium and phosphorus absorption and can worsen this condition by further suppressing parathyroid hormone 1. Discontinuing calcitriol will allow the parathyroid hormone level to increase, which should improve bone turnover and strength. The patient should continue other medications including phosphate binders (sevelamer) to help control phosphorus levels, as maintaining normal serum levels of phosphorus is critical for preventing abnormalities in parathyroid hormone metabolism and reducing morbidity and mortality 1. After stopping calcitriol, regular monitoring of calcium, phosphorus, and parathyroid hormone levels is essential to guide further management of her mineral bone disorder.
Key considerations in managing this patient's condition include:
- Monitoring and managing phosphorus levels to prevent hyperphosphatemia, which is associated with increased morbidity and mortality in CKD patients 1
- Avoiding hypercalcemia when treating secondary hyperparathyroidism, as it can worsen bone disease 1
- Regularly assessing and adjusting treatment based on trends in laboratory values rather than a single abnormal result 1
From the FDA Drug Label
Treatment of Hypercalcemia and Overdosage in Dialysis Patients and Hypoparathyroidism Patients General treatment of hypercalcemia (greater than 1 mg/dL above the upper limit of the normal range) consists of immediate discontinuation of calcitriol therapy, institution of a low-calcium diet and withdrawal of calcium supplements The patient has hypercalcemia (Calcium 5.4 mg/dL) and is undergoing peritoneal dialysis. The best next step in management is to discontinue calcitriol therapy and institution of a low-calcium diet and withdrawal of calcium supplements. Serum calcium levels should be determined daily until normocalcemia ensues.
- Discontinue calcitriol therapy
- Institution of a low-calcium diet
- Withdrawal of calcium supplements
- Monitor serum calcium levels daily until normocalcemia ensues 2
From the Research
Patient Management
The patient has a history of end-stage kidney disease and is undergoing peritoneal dialysis. The laboratory results show normal levels of 25-Hydroxyvitamin D, phosphorus, and calcium, but elevated alkaline phosphatase and intact parathyroid hormone. The X-ray reveals a stress fracture in the tibia.
Next Steps
Considering the patient's condition and laboratory results, the next steps in management could be:
- Evaluating the risk of fractures in the patient with chronic kidney disease, taking into account the same risk factors as the general population, such as low body weight, menopause, and personal or familial history of osteoporosis 3
- Assessing the patient's bone mineral density and considering the use of tools such as fracture risk assessment (Frax™) or quantitative computed tomography (QCT) to evaluate bone loss and fracture risk 3
- Reviewing the patient's current medication regimen, including epoetin alfa, sevelamer, calcitriol, and multivitamin, to ensure that it is optimized for managing mineral and bone disorders associated with chronic kidney disease 4, 5
- Considering the use of intermittent parathyroid hormone (PTH) administration to prevent further bone damage and reduce the risk of fractures, although its effectiveness and safety in patients with CKD-MBD need to be critically assessed in long-term prospective studies 4
Treatment Options
Treatment options for the patient could include:
- Vitamin D supplementation to maintain normal levels of 25-Hydroxyvitamin D, although the effect of supplementation on parathyroid hormone concentrations is inconsistent between studies 5
- Calcifediol or analogues to suppress parathyroid hormone, but with caution due to the potential increase in Fibroblast Growth Factor 23 (FGF23) 5
- Management of mineral and bone disorders associated with chronic kidney disease, including the use of phosphate binders and calcitriol or analogues, depending on the patient's stage of kidney disease and individual characteristics 4, 5