6928 Vitamin D excess in a patient with hypoparathyroidism after parathyroidectomy

Abstract Disclosure: Z. Zavgorodneva: None. A. Barsegian: None. F. Zhang: None. Introduction. We describe a case of a patient with mild persistent hypoparathyroidism after parathyroidectomy with autotransplantation, which was indicated for ESRD-related secondary hyperparathyroidism. The patient presented with nonspecific complaints and was found to have a high Vitamin D level after long-term moderate-dose Vitamin D supplementation. Case report. A 71-year-old male with a past medical history of end-stage renal disease (ESRD) undergoing hemodialysis for the past 18 years, as well as a history of parathyroidectomy with autoimplantation of parathyroid glands in the forearm in 2010 due to severe secondary hyperparathyroidism, presented to the hospital complaining of generalized weakness and lower extremity cramps that had been ongoing for a few weeks. Further investigations did not reveal evidence of infectious processes. A review of medications indicated the absence of statins among his outpatient medications. No focal neurological deficits or objective signs of muscle weakness were identified. Laboratory findings showed no significant metabolic derangements or haematological abnormalities. Inflammatory markers and creatine phosphokinase were within normal ranges. As part of the workup for generalized subjective weakness and ESRD, Vitamin D levels were checked, revealing a result of of120 ng/mL. The patient reported taking over-the-counter 2000 IU of Vitamin D twice daily for the past six years despite having a normal level of Vitamin D checked five years prior to admission. Calcium supplements were initiated in the postoperative period and continue to be administered at a dose of 600 mg daily. Analysis of the PTH-calcium axis demonstrated persistent mild hypoparathyroidism with hypocalcemia since the time of the surgery. However, there was an observed tendency for calcium levels to improve, especially in the last six years. Vitamin D supplement was discontinued, and the patient was subsequently discharged home with the continuation of physical therapy. Discussion. Explaining the origin of the high level of Vitamin D in this patient poses a challenge. There is limited data in the literature regarding the long-term effects of vitamin D use when the initial Vitamin D levels are normal. Additionally, there are numerous abstracts suggesting significantly higher doses of Vitamin D received for up to 6 years without any evident biochemical or clinical consequences. Moreover, the typical consequences of Vitamin D toxicity, such as hypercalcemia, can not be present in patients who underwent parathyroidectomy. Therefore, it is possible to consider that the severe generalized subjective weakness may be a sign of Vitamin D toxicity itself. Presentation: 6/1/2024