From the Research
The patient should follow up with nephrology as recommended for further evaluation of hypercalciuria, and in the meantime, continue calcium supplementation (1500 mg daily) and vitamin D supplementation to prevent bone loss. The patient's presentation of hypercalciuria with fluctuating parathyroid hormone (PTH) levels but normal serum calcium suggests secondary hyperparathyroidism likely due to renal calcium wasting rather than primary hyperparathyroidism, as supported by the negative parathyroid scan and neck ultrasound showing no evidence of parathyroid adenoma 1. The patient's urinary calcium excretion has been persistently elevated, ranging from 406 to 721 mg/day, significantly above normal, despite treatment attempts with thiazide diuretics. The discontinuation of hydrochlorothiazide was appropriate as it wasn't effectively controlling the hypercalciuria, and the patient requires potassium supplementation due to previous hypokalemia. Continuing calcium supplementation and vitamin D supplementation is appropriate to prevent bone loss, especially since the patient's ionized calcium was low-normal despite calcium supplementation, as seen in studies discussing the importance of calcium and vitamin D in bone health 2. However, it's essential to consider the potential risks of calcium and vitamin D supplementation, including the increased risk of kidney stones, as noted in some studies 3, 4. The normal bone density study is reassuring, but continued monitoring is warranted given the persistent calcium wasting. The nephrologist will likely investigate potential causes such as renal tubular acidosis, Dent disease, or other tubulopathies that can cause renal calcium wasting, and the patient should adhere to the recommended follow-up and treatment plan to manage their condition effectively. Key points to consider in the patient's management include:
- Continuing calcium supplementation (1500 mg daily) and vitamin D supplementation to prevent bone loss
- Monitoring urinary calcium excretion and adjusting treatment as necessary
- Investigating potential causes of renal calcium wasting
- Managing potassium levels due to previous hypokalemia
- Considering the potential risks of calcium and vitamin D supplementation, including kidney stones.