pediatrics
Hypophosphatemic Rickets
Treatment of Hypophosphatemic Rickets
Oral phosphate andcalcitriol Burosumabfor X-linked hypophosphatemia Treatment of hypophosphatemic rickets consists of neutral phosphate solution or tablets. Starting dose in children is 10 mg/kg (based on elemental phosphorus) 4 times a day. Phosphate supplementation lowers ionized calcium concentrations and further inhibitscalcitriolconversion, leading to secondary hyperparathyroidism and exacerbating urinary phosphate wasting. Therefore, oralvitamin Dis given ascalcitriol, initially 5 to 10 ng/kg 2 times a day. This, however, is not the case with HHRH or HHN (hypophosphatemia, hypercalcemia, and nephrocalcinosis), where 1,25-dihydroxyvitamin D3 levels are elevated and dosing withcalcitriolcan be detrimental. Phosphate dose may need to be increased to achieve bone growth or relieve bone pain. Diarrhea may limit oral phosphate dosage. Increase in plasma phosphate and decrease in alkaline phosphatase concentrations, healing of rickets, and improvement of growth rate occur. Hypercalcemia, hypercalciuria, and nephrocalcinosis with reduced renal function may complicate treatment. Patients undergoing treatment need frequent follow-up evaluations. is an anti–FGF-23 monoclonal antibody that has become the treatment of choice for X-linked hypophosphatemia (XLH) and has replaced the conventional therapy described above ( Treatment reference ). Dosing in children < 10 kg is started at 1 mg/kg (rounded to nearest 1 mg) subcutaneously every 2 weeks. For children 6 months to < 18 years and > 10 kg, starting dose is 0.8 mg/kg (rounded to the nearest 10 mg) subcutaneously every 2 weeks. For adults ≥ 18 years, starting dose is 1 mg/kg (rounded to the nearest 10 mg) subcutaneously every 4 weeks. The dose may be titrated upwards according to the Iron Deficiency upregulates expression of bone FGF-23 and can exacerbate conditions with high FGF-23 levels/impaired FGF cleavage. Therefore, Adults with oncogenic rickets may dramatically improve once the mesenchymal tumor that causes the disorder is removed. Otherwise, oncogenic rickets is treated withcalcitriol5 to 10 ng/kg orally 2 times a day and elemental phosphorus 250 mg to 1 g orally 3 or 4 times a day. 1.Imel EA, Glorieux FH, Whyte MP, et al:Burosumabversus conventional therapy in children with X-linked hypophosphataemia: A randomised, active-controlled, open-label, phase 3 trial.Lancet393(10189):2416–2427, 2019. doi: 10.1016/S0140-6736(19)30654-3.Clarification and additional information.Lancet394(10193):120, 2019. doi: 10.1016/S0140-6736(19)31426-6 