Endocrine Abstracts

Background: Vitamin D supplements are readily available without prescription. Although vitamin D toxicity is infrequent, rising use may lead to an increase in reported cases. We present a case of hypercalcemia and acute kidney injury due to excess vitamin D intake

Case: A 46-year-old woman was admitted with three-month history of lethargy, reduced oral intake, and constipation. She also experienced intermittent nausea and vomiting, but did not report any abdominal pain or significant weight loss. Her medical history included bronchiectasis and reactive arthritis. She had a COVID-19 infection six months ago, and since then, her symptoms had progressively worsened. Blood tests revealed elevated calcium 3.44mmol/l (normal: 2.20-2.60mmol/l), and low phosphate at 0.66mmol/l, along with acute kidney injury. Further investigations revealed suppressed parathyroid hormone (0.8 pmol/l; normal range: 1.6-7.2) and an increased 24-h urine calcium/creatinine ratio of 2.14mmol/mmolcreat (normal range: 0-0.70). Her thyroid function tests, B12, folate, ferritin, magnesium, albumin, and angiotensin-converting enzyme levels were all normal. No urinary Bence Jones protein was detected, and serum immunoglobulin levels were normal. A CT scan of the thorax, abdomen, and pelvis did not reveal any abnormalities. Upon further questioning, patient disclosed that she had been taking over-the-counter vitamin D drops and calcium supplements since her COVID-19 infection, as she believed they were beneficial and continued to take them. Her vitamin D3 levels were significantly elevated at 614 nmol/l, with a low vitamin D2 level (< 8 nmol/l). With intravenous fluids and discontinuation of vitamin D, her kidney function and calcium improved, and at six-month follow-up, remained normal.

Conclusion: Hypervitaminosis D is an infrequently reported condition that typically arises from an excessive intake of vitamin D. It is crucial to acknowledge that, though rare, hypervitaminosis D can cause hypercalcemia. Patients should receive proper education about benefits and potential risks of vitamin D supplementation.