Question
How should vitamin D-resistant osteomalacia be treated?
Answer
Vitamin D-resistant osteomalacia can be divided into two types: hypophosphatemic and hypocalcemic. For the common hypophosphatemic form of vitamin D-resistant rickets, the treatment principles include preventing skeletal deformities, raising blood phosphorus levels to above 0.97mmol/L (3mg/dl) to promote ossification, and maintaining normal growth rates while avoiding symptoms of hypercalcemia and hyperuricemia caused by excessive vitamin D. Here’s a brief overview of the treatment measures: Firstly, simply taking oral phosphate may require the use of phosphate preparations. Generally, 18g of sodium dihydrogen phosphate and 145g of sodium monohydrogen phosphate are used, dissolved in 1000ml of water, taken five times a day, with each dose ranging from 15 to 20ml. A daily intake of 2g of elemental phosphorus is required. Phosphate preparations have an unpleasant taste and may cause diarrhea. To enhance intestinal absorption of phosphorus, it is best to also administer vitamin D or DHT. Secondly, the simultaneous use of phosphate and vitamin D involves a daily dosage of 1 to 50,000 IU of vitamin D, with a maximum not exceeding 100,000 IU. Vitamin D can accumulate in body fat, potentially leading to toxicity, while DHT, a drug similar to vitamin D, is less likely to accumulate in body fat and is considered safer. The initial dose for the first 2 to 4 weeks of treatment should be close to 2mg/d, and then the maintenance dose can be 0.5 to 1.5mg/d.