Tertiary hyperparathyroidism in X-linked hypophosphatemic rickets.

Area of Science:

• Endocrinology
• Pediatric Nephrology
• Metabolic Bone Disease

Background:

• X-linked hypophosphatemic rickets (XLH) is a rare genetic disorder characterized by phosphate wasting and bone deformities.
• Treatment typically involves calcitriol and oral phosphate supplementation to correct hypophosphatemia and rickets.
• Long-term management requires careful monitoring to prevent complications.

Observation:

• A case of tertiary hyperparathyroidism developed in an XLH patient receiving high doses of oral phosphate (2.4-3.6 g/day) and calcitriol.
• The patient self-adjusted phosphate intake based on serum phosphate levels, leading to sustained high intake.
• Tertiary hyperparathyroidism is an uncommon but significant complication in XLH patients undergoing treatment.

Findings:

• High phosphate administration may contribute to parathyroid gland hyperplasia and tertiary hyperparathyroidism in XLH.
• Sustained high phosphate levels can exacerbate the condition, potentially leading to secondary hyperparathyroidism.
• Regular monitoring of serum calcium, phosphate, alkaline phosphatase, and parathyroid hormone is essential.

Implications:

• Avoiding excessive phosphate supplementation is critical to prevent parathyroid gland stimulation in XLH patients.
• Early detection of secondary hyperparathyroidism allows for reversible treatment with calcitriol and dose reduction of phosphate.
• This case highlights the importance of individualized treatment adjustments and vigilant monitoring in managing XLH.