1. Introduction Case Description Discussion
Vitamin D Toxicity, A Case Report
Michelle Valentine, D.O., and Tom Schulz, M.D.,
College of Medicine, University of Arkansas Northwest Campus,
Fayetteville, Arkansas, Drake Rippelmeyer, M.D., Veterans Health Care
System of the Ozarks, Fayetteville, Arkansas
Introduction
10-24 ng/mL
25-80 ng/mL
> 150 ng/mL(1)
Mild to moderate deficiency
Toxic effects
Optimal Levels
Vitamin D intoxication has been rarely reported in the literature (2,3). However, it is the opinion of the authors that Vitamin D toxicity will become more common due to increases in Vitamin D supplementation.
Thankfully the patient in this article was prescribed high doses of Vitamin D by his physician resulting in documentation in the patient’s medical record. This allowed for quick recognition that toxicity could be the driving factor for the patient’s symptoms and hypercalcemia.
It is important that practitioners routinely inquire about supplement use and include Vitamin D toxicity in the differential diagnosis of hypercalcemia. Physicians should also use caution when prescribing high-dose cholecalciferol and monitor calcium and Vitamin D 25-OH levels frequently for early detection of toxicity.
With the recent prevalence of Vitamin D supplementation, the risk for toxicity has increased.
Sales of Vitamin D supplements have doubled in the last 8-10 years(4)
This may be due to reports that approximately 40% of adults are Vitamin D deficient prompting clinicians to prescribe Vitamin D more frequently (5, 6, 7)
In the National Health and Nutrition Examination Survey, up to 50% of adults reported taking supplements (8), and as most clinicians are already aware, many patients do not disclose their supplement use
Case Description
Cause: Patient was noted to be taking 50,000 IU Cholecalciferol (Vitamin D3) daily as prescribed by his primary care provider 5 months prior to admission due to medical error.
Treatment for patient:
There are no known long-term side-effects from appropriately treated hypercalcemia secondary to iatrogenic Vitamin D toxicity.
Patient: 70 year old male
Previous medical history: laryngeal carcinoma, esophageal strictures, Crohn’s Disease, hypothyroidism
Differential Diagnosis: malignancy, hyperparathyroidism, hyperthyroidism and kidney disease
Workup: CBC, CMP, iPTH, PTHrp, TSH, CT chest/abdomen/pelvis and EGD
Pertinent Findings:
Calcium
(Normal = 8.50 – 10.20)
Ionized calcium*
(Normal = 4.4 – 5.4)
Vitamin D 25-0H – 203.9
*Most active form of calcium
Isotonic IV Fluids
Calcitonin (reduction in calcium = sensitivity. Does can be repeat Q6-12 hours)
Pamidronate (zoledronic acid also an option)
Patient’s symptoms for past months:
Weakness
Confusion
Weight loss
Nausea
Discussion
Most patients with symptomatic hypercalcemia have an underlying malignancy or hyperparathyroidism, but these diagnoses were unlikely given the patient's negative workup. That coupled with the maintenance of normal calcium levels for 4 months after discontinuing high-dose Vitamin D suggests hypercalcemia was secondary to toxicity.
References: 1. Holick MF. Vitamin D deficiency.  N Engl J Med. 2007;357(3): Hathcock JN, Shao A, Vieth R, Heaney R. Risk assessment for vitamin D.  Am J Clin Nutr. 2007;85(1): Jansen TL, Janssen M, de Jong AJ. Severe hypercalcaemia syndrome with daily low-dose vitamin D supplementation.  Br J Rheumatol. 1997;36(6): The Evolving Natural Lifestyle: SPINS Natural Products Market Review. In: Series of report. Mintel International Group Ltd December. 5. Forrest KY, et.al Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res 31: Holick MF, et.al Evaluation, treatment, and prevention of vitamin d deficiency: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 96: Qato DM, et.al Use of prescription and over-the-counter medications and dietary supplements among older adults in the United States. JAMA 300: Radimer K, et.al Dietary supplement use by US adults: data from the National Health and Nutrition Examination Survey, Am J Epidemiol 160: