Hypercalcemic crisis due to vitamin D toxicity

Abstract

Patient: 30-year-old female. History of Present Illness: The patient presented to the emergency department with a 5-day history of worsening abdominal pain, nausea, and vomiting. She had a multiyear history of gastrointestinal discomfort, but no formal workup or endoscopy to date. The patient also stated that she had a thyroid disorder, although she had not previously been treated for thyroid disease. She stated that she had been taking multiple vitamin supplements, including vitamins A, B, and D, as well as a calcium-containing zeolite supplement. Physical Examination: Her abdomen was diffusely tender but non-distended, with no masses or hepatosplenomegaly noted. She was afebrile (T=35.5°C) with normal blood pressure (124/78 mm Hg), normal respiratory rate (16/min), and an O2 saturation of 100% on room air. Radiographic Findings: Abdominal computerized tomography (CT) suggested that a "difficult to localize" small bowel obstruction may be present. Principal Laboratory Findings: See Table 1. Serum electrolyte testing demonstrated low sodium, low potassium, and markedly elevated calcium (Ca2+) of 18.4 mg/dL. Subsequently, ionized Ca2+ was also measured and found to be elevated while parathyroid hormone (PTH) was low. Serum and urine protein electrophoresis were normal with no monoclonal proteins detected. The patient was found to have a markedly elevated 25-hydroxyvitamin D (25[OH]D) level of 409 ng/mL measured by DiaSorin immunoassay (reference interval: optimal, 30-80 ng/mL; possible toxicity, >150 ng/mL) and an elevated 1,25-dihydroxyvitamin D (1,25[OH]2D) level measured by a DiaSorin radioimmunoassay. Further discussion with the patient revealed that she had been taking large quantities of vitamin D for an unknown period of time.