Vitamin D intoxication (VDI) is a well-known cause of hypercalcemia in children and leads to serious kidney, heart, and neurological problems. In the treatment of VDI, the goal is to correct hypercalcemia. Our aim was to evaluate the clinical features of patients with VDI, identify the causes of VDI in our region, and help guide precautions and treatment of VDI.

The medical records of patients with VDI presenting between January 2015 and December 2019 were retrospectively analyzed.

In total, 38 patients aged 0.3–4 years including 20 males (52.6%) were included in the study. Vomiting (65.8%), loss of appetite (47.4%), and constipation (31.6%) were the most common symptoms. The cause of intoxication was prescribed D₃ vials in 23 patients, non-prescribed D₃ vials in nine patients, and incorrectly produced fish oil supplement in six patients. Admission serum calcium and 25 (OH) D levels were 3.75±0.5mmol/L and 396±110ng/mL, respectively. A statistically significant correlation was found between the serum calcium levels at the time of diagnosis and the dose of vitamin D received, serum 25 (OH) D, phosphorus, and parathyroid (PTH) levels. Nephrocalcinosis was present in 15 (39.5%) patients. The mean time to achieve normocalcemia was 6.18±2 days. The mean time to achieve normocalcemia in patients treated with pamidronate was 5.94±0.7 days.

Stoss therapy should not be administered for children of families with problems of adherence to treatment. It should be noted that VDI may develop as a result of improperly produced nutritional supplements. General practitioners and pediatricians must be aware of VDI risks and explain them to parents. Pamidronate is effective for treating VDI in children.