Severe Hypocalcemia and Vitamin D Deficiency in Adolescence - A Case Series

Abstract

Background: Hypocalcemia due to vitamin D (vit D) deficiency is uncommon among adolescents in the US. Only 3% to 6% of those ages 12- to 19-years-old have a vit D level <12 ng/ml.1 We present three cases of severe hypocalcemia secondary to vit D deficiency in non-obese adolescents with restricted diets and limited sun exposure. Clinical Cases: A 14-year-old Ethiopian male with history of absence seizures presented with bloody stool. Incidentally, labs revealed: Ca 5.6 (8.4–10.2) mg/dL, iCal 0.71 (1.2–1.38) mmol/L, PTH 295.1 (10.0–65.0) pg/mL, 25(OH)D <4 (20–100) ng/mL, Mg 1.9 (1.7–2.2) mg/dL, PO4 3.8 (2.5–4.5) mg/dL. He endorsed weight loss and knee pain, but denied paresthesias, tetany and seizures. He was a vegetarian and had minimal sun exposure. EKG and femur X-ray were unremarkable. He was started on IV calcium gluconate initially. Oral calcium carbonate and cholecalciferol were started on days three and four. He was discharged on day ten with iCal 0.84 on oral calcium carbonate and calcitriol.A 16-year-old male with history of autism, ADHD and bipolar disorder presented with a seizure. Labs revealed: Ca 5.7, iCal 0.62, PTH 372, 25(OH)D <4, Mg 1.9, PO4 3.5. Exam showed tetany, carpopedal spasms and positive Trousseau and Chvostek signs. EKG revealed prolonged QTc of 480 (<450) ms. He had a restricted diet and minimal sun exposure. His mother described his gait as “waddling” for the past two years. X-ray revealed bilateral femoral head fractures and evidence of rickets. He underwent bilateral surgical repair. He was started on IV calcium gluconate initially. Oral calcium carbonate and cholecalciferol were started on days two and four. He was discharged on day 14 with iCal 1.01 on oral calcium carbonate and cholecalciferol.A 16-year-old male with history of severe food allergies and restricted diet presented with a seizure. He visited urgent care three months prior for perioral tingling, muscle cramps and chest pain. He started a multivitamin for “low Ca” and “prolonged QTc.” The ED labs revealed: Ca 4.8, PTH 414.8, 25(OH)D 11, Mg 1.9, PO4 5.0, Alk Phos 539 (44–147) IU/L. Exam showed upper extremity twitching and QTc was 543 ms. He received 2 g calcium gluconate IV, then began oral calcium carbonate and cholecalciferol and continued supplementation following discharge on day six. Conclusions: Vit D deficiency among adolescents is re-emerging, likely due to decreasing sun exposure, unbalanced diets and increasing obesity.2 Adolescents with restricted diets due to allergy or behavioral disorders may be at higher risk of vit D deficiency. Increased screening of high-risk adolescents may lead to early identification of cases.