Vitamin D Toxicity Due to Self-Medication During the COVID-19 Pandemic – a Case Report

Abstract Introduction During the COVID-19 pandemic, vitamin D was used along with vitamin C and zinc as a preventive and curative therapy against SARS-CoV-2 infection. Vitamin D toxicity, even if it is rare, occurs when serum concentrations exceed 150 ng/mL and is usually manifested by hypercalcemia phenomena. Case report We hereby report a case of two twin sisters who self-medicated with vitamin D in a dose of 4 × 4,000 IU/day for almost 10 months as a method of ‘protection’ against COVID-19, influenced by mass media advertising. The patients presented to the emergency department with hypervitaminosis D-related symptoms such as hypertension, headache, nausea, vomiting, and diffuse abdominal pain. Laboratory investigations revealed high levels of vitamin D and calcium. Conclusions Vitamin D toxicity can lead to difficulties in positive and differential diagnosis because of the multiple complications of hypercalcemia.