Vitamin D Induced Hypercalcemia In Myelodysplastic Syndrome: A Case of Uncommon But Reversible Cause

Hypercalcemia is a common metabolic complication, most frequently associated with primary hyperparathyroidism and malignancy, while vitamin-D intoxication is an under-recognized but potentially reversible cause, particularly in patients with underlying comorbidities; a 63-year-old male with myelodysplastic syndrome presented with gastrointestinal symptoms and was found to have severe hypercalcemia with suppressed parathyroid hormone levels, with medication review revealing prolonged vitamin-D supplementation as the probable cause, and the patient was managed with cessation of vitamin-D, intravenous hydration, calcitonin, and zoledronic acid, resulting in normalization of serum calcium levels and clinical recovery, emphasizing the need for cautious use and regular monitoring of vitamin-D supplementation, especially in patients with comorbid conditions that predispose them to metabolic complications.