Case History: A 68-year-old gentleman was admitted to the hospital following a history of weight loss, lethargy, tiredness for about 6 months. His past history includes hiatus hernia, esophagitis and kidney stones. He reported taking over the counter vitamin D (60,000 IU daily) for more than 2 years. He was not on any other regular medications.
Investigations: His initial investigations showed acute kidney injury with severe PTH independent hypercalcaemia due to vitamin D toxicity [Creatinine: 467 umol/l (59-107 umol/l), Adjusted Calcium 3.26 mmol/l (2.2-2.6 mmol/l), PTH: 0.7 pmol/l (1.3-9.3pmol/l)]. His Total Vitamin D >525 nmol/l. CT TAP didnt show any abnormalities.
Results and treatment: Initially, he was treated with fluid resuscitation with slight initial improvement in his calcium levels and renal function. Subsequently, he was given one dose of IV Pamidronate 30mg after discussion with the renal team and due to limited treatment options for severe hypercalcaemia. He was then treated with increase in fluid intake with a trial of prednisolone 30mg once a day for a period of 1-2 weeks but due to side effects (fluid retention and ankle oedema), they were stopped. He then had a trial of ketoconazole 200mg once a day which resulted in significant improvement of calcium levels. Ketoconazole had to be stopped due to transaminitis. Subsequently, he was followed up regularly on ultra-low calcium diet and increase in fluid intake with intermittent IV fluid resuscitation with gradual improvement in vitamin D and calcium levels. Although, his calcium levels have now normalised, vitamin D levels have remained in toxic range for 17 months since initial presentation (Results in the table).
|Date||Adjusted Calcium level||Vitamin D||Creatinine levels|
|13/08/2020||3.26 mmol/l||>525 nmol/l||419 umol/l|
|08/10/2020||2.85 mmol/l||>525 nmol/l||306 umol/l|
|09/12/2020||2.67 mmol/l||>525 nmol/l||249 umol/l|
|22/03/2021||2.51 mmol/l||470 nmol/l||232 umol/l|
|21/01/2022||2.60 mmol/l||285 nmol/l||184 umol/l|
Conclusion and points for discussion: Vitamin D supplements are readily available over the counter without any restrictions. Due to its pharmacokinetic properties, it is stored in the body for long term once ingested. We hereby discuss calcium fall in our patient over a period of time with the different interventions, evidence and their mechanism of action. We will also discuss various other treatment options for vitamin D toxicity.