Hypervitaminosis D (Q39979)

Hypervitaminosis D is secondary to excessive intake of vitamin D. It can occur with long-term high intake or with a substantial, acute ingestion. Excess amounts result in abnormally high concentrations of calcium and phosphate in the serum. The signs and symptoms of vitamin D intoxication are secondary to hypercalcaemia. Gastrointestinal manifestations include nausea, vomiting, constipation, abdominal pain and pancreatitis. Possible cardiac findings are hypertension, decreased Q-T interval and arrhythmias. The central nervous system effects of hypercalcaemia include lethargy, hypotonia, confusion, disorientation, depression, psychosis, hallucinations and coma. Hypercalcaemia impairs renal concentrating mechanisms, which can lead to polyuria, dehydration and hypernatremia. Hypercalcaemia can also lead to acute renal failure, nephrolithiasis and nephrocalcinosis, which can result in chronic renal insufficiency. Deaths are usually associated with arrhythmias or dehydration.