From the Guidelines
Hypervitaminosis D symptoms typically manifest as hypercalcemia, hyperphosphatemia, suppressed parathyroid hormone, and hypercalciuria, which can lead to nausea, vomiting, weakness, and kidney problems. These symptoms occur when excessive vitamin D builds up in the body, usually from supplement overuse rather than from diet or sun exposure 1. Common symptoms include:
- Nausea and vomiting
- Weakness and frequent urination
- Kidney problems and bone pain
- Calcium deposits in soft tissues The condition develops because too much vitamin D increases calcium absorption, leading to hypercalcemia (high blood calcium) 1. Early signs may include digestive issues like constipation, loss of appetite, abdominal pain, and excessive thirst. As it progresses, patients may experience confusion, fatigue, irregular heartbeat, and in severe cases, kidney failure. Treatment involves stopping vitamin D supplements, limiting dietary calcium, increasing fluid intake, and sometimes medications like bisphosphonates or corticosteroids to lower calcium levels. In severe cases, hospitalization may be necessary. Most people should not exceed 4,000 IU of vitamin D daily unless specifically directed by a healthcare provider, as the body cannot effectively eliminate excess vitamin D due to its fat-soluble nature. It is essential to be aware of the risks associated with vitamin D toxicity, as the 25-(OH)D level associated with toxicity is well above the level considered to be sufficient 1.
From the Research
Hipervitaminosis D Symptoms
- Confusion, apathy, recurrent vomiting, abdominal pain, polyuria, polydipsia, and dehydration are common clinical symptoms of vitamin D toxicity (VDT) or hypervitaminosis D 2
- Severe hypercalcemia is a potentially life-threatening complication of hypervitaminosis D, and its symptoms include nausea, vomiting, dehydration, confusion, somnolence, and coma 3, 4
- Mild hypercalcemia due to hypervitaminosis D may be asymptomatic, but can cause constitutional symptoms such as fatigue and constipation in approximately 20% of people 4
- Hypercalcemia caused by hypervitaminosis D can also lead to nephrocalcinosis, a condition characterized by the deposition of calcium salts in the kidneys, which can impair renal function 3
Treatment and Management
- Treatment of hypercalcemia due to hypervitaminosis D typically involves hydration, glucocorticoids, and bisphosphonates 5, 4
- Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption, such as in vitamin D intoxication 4
- Bisphosphonates, such as zoledronic acid or pamidronate, can reduce bone resorption and lower serum calcium levels 3, 4
- In some cases, treatment with calcitonin may also be effective in reducing serum calcium levels 3
Diagnosis and Prevention
- Serum 25-hydroxyvitamin D [25(OH)D] concentrations higher than 150 ng/ml (375 nmol/l) are a hallmark of VDT due to vitamin D overdosing 2
- Laboratory testing during routine clinical examinations may reveal asymptomatic hypercalcemia caused by the intake of vitamin D, even in doses recommended for the general population and considered safe 2
- Increased public awareness of vitamin D-related health benefits may increase the risk of VDT due to self-administration of vitamin D in doses higher than recommended for age and body weight or even higher than the established upper limit intake values 2