Annals of Medicine and Surgery · 10 authors, 2 centres
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A 2.5-month-old infant developed life-threatening vitamin D toxicity (serum calcium 6.0 mmol/L, 25-OHD >160 ng/mL) due to a manufacturer error that caused the supplement to contain 42,000 IU instead of 800 IU per dose. The infant presented with failure to thrive, hypercalcemia, nephrocalcinosis, and urinary tract infection. This case highlights the critical need for strict quality control in supplement manufacturing and careful monitoring of vitamin D dosing in infants.
**Background:** Vitamin D supplementation is recommended for breastfed infants due to low vitamin D content in breast milk (20–60 IU/L). However, increasing use of supplements has led to more cases of intoxication and overdose, causing hypercalcemia and related complications. This case report describes an unusual instance of vitamin D toxicity in a healthy term infant due to a concentration error in the supplement.
**Methods:** This is a case report following SCARE guidelines. A 2.5-month-old female infant was referred to the pediatric ward with fever, nasal blockage, refusal to feed, and failure to thrive. She had been receiving a vitamin D3 supplement (Biodee, batch no. 621-750) since the third day of birth. Investigations included complete blood count, urine culture, liver and renal function tests, serum calcium, phosphorus, 25-hydroxy vitamin D (25-OHD), intact parathyroid hormone (iPTH), spot urinary calcium, and abdominal ultrasound.
**Key Results:** The infant's birth weight was 3120 g, but at presentation weight was 3400 g (<−3 z-score), length 56 cm (0 to −2 z-score), and head circumference 36 cm (−2 to −3 z-score). Serum total calcium was elevated to 6.0 mmol/L (normal 2.1–2.5), 25-OHD >160 ng/mL (normal 30–50), and iPTH suppressed to 3.7 pg/mL (normal 15–68.3). Serum phosphorus was normal at 6.3 mg/dL. Urine culture grew Escherichia coli, confirming urinary tract infection. Abdominal ultrasound revealed bilateral medullary nephrocalcinosis. Further investigation revealed that the infant received 0.5 mL of vitamin D supplement containing 42,000 IU instead of the intended 800 IU, a dose 21 times the upper limit of the toxic dose (1800 IU in children). The infant was treated with intravenous fluids and prednisolone, and the supplement was discontinued. Over 2 months, serum calcium and 25-OHD normalized, and weight improved to 6400 g at 4.5 months (0 to −2 z-score). However, follow-up ultrasound showed persistent bilateral medullary nephrocalcinosis and new foci of linear calcification in the right hepatic lobe.
**Clinical Implications:** This case demonstrates that manufacturer errors in vitamin D supplement concentration can cause severe, life-threatening hypervitaminosis D in otherwise healthy infants, leading to hypercalcemia, nephrocalcinosis, and failure to thrive. Even after correction of calcium and vitamin D levels, renal and hepatic calcifications may persist. The authors emphasize the need for strict quality control in pharmaceutical manufacturing, correct dilution and conversion procedures, and careful supervision of vitamin D supplementation by healthcare providers. This case serves as an alert for pharmacists, clinicians, and parents to prevent similar incidents.