From the Guidelines
The initial approach to managing hypercalcemia, hypophosphatemia, and low Parathyroid Hormone (PTH) in children involves treating them with a combination of oral phosphorus and active vitamin D, as soon as the diagnosis is established, with an initial dose of 20–60mg/kg body weight daily of elemental phosphorus and 20–30ng/kg body weight daily of calcitriol or 30–50ng/kg body weight daily of alfacalcidol 1. This approach is based on the clinical practice recommendations for the diagnosis and management of X-linked hypophosphatemia, which suggests that treating children with overt X-linked hypophosphatemia phenotype with a combination of oral phosphorus and active vitamin D can improve rickets, growth, and alkaline phosphatase levels 1.
Key Considerations
- The dose of phosphate supplements should be adjusted according to the improvement of rickets, growth, alkaline phosphatase, and parathyroid hormone levels, with a progressive increase in the dose in cases of insufficient clinical response, but avoiding doses >80mg/kg daily to prevent gastrointestinal discomfort and hyperparathyroidism 1.
- Phosphate supplements should be taken as frequently as possible, for example, 4–6 times daily in young patients with high alkaline phosphatase levels, and the frequency can be lowered to 3–4 times daily when alkaline phosphatase has normalized 1.
- To prevent nephrocalcinosis, calciuria levels should be kept within the normal range, and large doses of phosphate supplements should be avoided, with measures such as regular water intake, administration of potassium citrate, and limited sodium intake if necessary 1.
Monitoring and Adjustments
- Regular monitoring of serum calcium, phosphorus, magnesium, and renal function is essential, with frequency determined by severity, to adjust the treatment plan accordingly 1.
- Secondary hyperparathyroidism should be managed by increasing the dose of active vitamin D and/or decreasing the dose of oral phosphate supplements, and treatment with calcimimetics might be considered in patients with persistent secondary hyperparathyroidism despite these measures 1.
From the Research
Initial Approach to Managing Hypercalcemia, Hypophosphatemia, and Low Parathyroid Hormone (PTH) in Children
- The initial approach to managing hypercalcemia in children involves hydration, with the administration of sufficient quantities of isotonic saline sometimes with loop diuretic agents being the first and fundamental step 2.
- In cases of severe hypercalcemia, calcitonin can be administered for immediate short-term management, with glucocorticoids also being effective in certain cases, such as hypercalcemia due to lymphoma or granulomatous diseases 3.
- For long-term control of severe or symptomatic hypercalcemia, the addition of bisphosphonates, such as zoledronic acid or pamidronate, is typically required 3, 4.
- In children with hypercalcemia due to diabetic ketoacidosis, rigorous hydration with the correct fluid choice can usually correct the hypercalcemia, with specific medications to treat the hypercalcemia often being avoided 5.
Considerations for Hypophosphatemia and Low PTH
- The management of hypophosphatemia and low PTH in children with hypercalcemia requires careful consideration of the underlying cause of the hypercalcemia, as well as the potential effects of treatment on phosphate and PTH levels 6.
- In some cases, treatment of the underlying cause of the hypercalcemia, such as primary hyperparathyroidism, may be necessary to manage hypophosphatemia and low PTH 4.
Treatment Options
- Treatment options for hypercalcemia in children include:
- Hydration with isotonic saline
- Loop diuretic agents
- Calcitonin
- Glucocorticoids
- Bisphosphonates, such as zoledronic acid or pamidronate
- The choice of treatment will depend on the severity of the hypercalcemia, the underlying cause, and the presence of any other medical conditions 2, 3, 4.