Definition
- Toxicity from excess vitamin D intake causing hypercalcaemia, hyperphosphataemia and hypercalciuria
Aetiology
- Excessive supplementation, including children over treated for rickets
- Formulation or prescribing errors with high dose preparations
- Granulomatous disease and lymphoma produce a similar picture through excess calcitriol
Clinical Features
- Mimics hyperparathyroidism clinically through hypercalcaemia
- Bones, stones, abdominal moans and psychic groans
- Lassitude, somnolence, confusion and depression
- Polyuria, polydipsia and dehydration
- Anorexia, vomiting, constipation and abdominal pain
- Failure to thrive in children
Investigations
- High calcium and high 25 hydroxyvitamin D with suppressed PTH
- Phosphate normal or raised, unlike primary hyperparathyroidism
- Hypercalciuria and impaired renal function
- Shortened QT on ECG
- X-ray shows dense metaphyseal bands in children, metastatic soft tissue and vascular calcification
Differential Diagnosis
- Primary hyperparathyroidism, with raised PTH
- Malignancy related hypercalcaemia
- Sarcoidosis
- Immobilisation hypercalcaemia
Management
- Stop vitamin D and calcium supplements and restrict dietary calcium
- IV normal saline to restore volume and promote calciuresis
- Loop diuretic only after rehydration
- Glucocorticoids reduce gut calcium absorption
- Bisphosphonate or calcitonin for severe or persistent hypercalcaemia
Complications
- Nephrocalcinosis and chronic kidney disease
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.