From the Guidelines
Hypervitaminosis D is a condition that requires immediate medical attention, and treatment involves stopping all vitamin D supplements and limiting dietary calcium, with medications and hospitalization necessary in severe cases, as supported by the US Preventive Services Task Force recommendation statement 1.
Causes and Symptoms
Hypervitaminosis D is caused by excessive vitamin D intake, leading to high calcium levels in the blood. Symptoms include:
- Nausea and vomiting
- Weakness and frequent urination
- Bone pain and kidney problems
- Confusion or coma in extreme cases
Treatment and Management
Treatment involves:
- Immediately stopping all vitamin D supplements
- Limiting dietary calcium
- Increasing fluid intake
- Avoiding sun exposure
- Medications like bisphosphonates, corticosteroids, or calcitonin to lower calcium levels in severe cases
- Hospitalization for IV fluids and monitoring if symptoms are severe
Importance of Monitoring
Regular blood tests are crucial during recovery to monitor calcium and vitamin D levels, as supported by the studies 1. Most people recover fully once vitamin D levels normalize, but kidney damage may be permanent in severe cases.
Prevention
Prevention is key, and individuals should be aware of the risks of excessive vitamin D intake, especially from supplements, and consult with their healthcare provider before taking any vitamin D supplements, as recommended by the US Preventive Services Task Force 1.
From the Research
Definition and Causes of Hypervitaminosis D
- Hypervitaminosis D is a relatively uncommon etiology of hypercalcemia, usually caused by very high doses of vitamin D, mostly secondary to erroneous prescription or administration of vitamin D, and less commonly, contaminated foods or manufacturing errors of vitamin D-containing supplements 2.
- The use of dietary supplements is highly prevalent and should be considered a potential source of toxicity when an alternative source cannot be found, regardless of the product label 2.
Symptoms and Diagnosis of Hypervitaminosis D
- Symptoms of hypervitaminosis D can include nonspecific symptoms such as fatigue, gastrointestinal complaints, acute kidney injury, and hypercalcemia 2.
- Investigations may show markedly elevated 25-hydroxyvitamin D levels, and mass spectrometry analysis of supplements can estimate vitamin D content 2.
- Hypercalcemia, hypercalciuria, and hyperphosphatemia are considered initial signs of vitamin D intoxication, and prolonged consumption of vitamin D supplementation may induce these conditions even without developing hypervitaminosis D 3.
Treatment of Hypervitaminosis D
- Treatment of hypervitaminosis D may include intravenous hydration, calcitonin, and pamidronate, and patients may require low-calcium diets and laboratory testing for months after exposure 2.
- Pamidronate, a bone resorption inhibitor, has been used to treat hypercalcemia secondary to acute vitamin D intoxication and can normalize calcium concentrations within 24 hours 4, 5.
- The hypercalcemia of vitamin D intoxication is mediated by increased bone resorption, and bisphosphonates such as pamidronate have a role in its management 5.
Prevalence of Hypervitaminosis D
- Hypervitaminosis D is found in approximately 1.86% of samples, with 11.1% of these displaying hypercalcemia 6.
- Hypercalcemia due to vitamin D represents less than 4% of the total hypervitaminosis D detected and less than 0.1% of the tests performed 6.
- A highly variable response is observed, and most subjects present hypercalcemia at serum concentrations of 25-OH-vitamin D less than 375 nmol/L 6.