What is the treatment for vitamin D toxicity?

Treatment for Vitamin D Toxicity

The treatment for vitamin D toxicity should include discontinuation of vitamin D supplementation, a low calcium and phosphorus diet, intravenous hydration with saline, and possibly loop diuretics, glucocorticoids, calcitonin, and bisphosphonates for severe cases. 1, 2

Diagnosis of Vitamin D Toxicity

• Vitamin D toxicity is typically defined as serum 25(OH)D levels exceeding 150 ng/ml (375 nmol/L) 1, 2
• Clinical manifestations include hypercalcemia and its symptoms: fatigue, weakness, nausea, vomiting, altered mental status, constipation, and kidney injury 1, 3
• Laboratory findings typically show:
  • Hypercalcemia (often >11 mg/dL)
  • Normal or high serum phosphorus
  • Normal or low alkaline phosphatase
  • Low serum parathyroid hormone (PTH)
  • High urine calcium/creatinine ratio 2

Treatment Algorithm

For Mild to Moderate Toxicity (Calcium <14 mg/dL, minimal symptoms):

1. Immediate discontinuation of all vitamin D supplements 2, 4
2. Low calcium and phosphorus diet to reduce calcium absorption 2
3. Adequate hydration to promote calcium excretion 2
4. Regular monitoring of serum calcium, phosphorus, and renal function 1

For Severe Toxicity (Calcium >14 mg/dL or significant symptoms):

1. Emergency intervention is necessary due to risk of cardiac, neurological, renal, and gastrointestinal complications 2
2. Aggressive intravenous hydration with normal saline to increase renal calcium excretion 2, 3
3. Loop diuretics (e.g., furosemide) after adequate hydration to enhance calcium excretion 2
4. Glucocorticoids to decrease intestinal calcium absorption and vitamin D activity 2
5. Calcitonin for rapid but short-term reduction of serum calcium 2, 3
6. Bisphosphonates for persistent hypercalcemia 2, 3

Duration of Treatment

• Effects of vitamin D toxicity may persist for months since vitamin D is stored in fat tissues 2
• Normalization of serum calcium can occur within a week of stopping supplementation, but complete normalization of vitamin D levels may take 6-18 months 4
• Regular monitoring of calcium levels and renal function is essential during recovery 1, 4

Special Considerations

• Patients with granulomatous disorders (e.g., sarcoidosis) are at higher risk due to dysregulated vitamin D metabolism 1
• Acute kidney injury is common in vitamin D toxicity and may require temporary renal support 3, 5
• The most common cause of vitamin D toxicity is iatrogenic overdose due to prescription errors or manufacturing errors in supplements 3, 5

Prevention of Recurrence

• Educate patients about the potential dangers of vitamin D overdose 4
• Question parents of infants about dietary supplements to avoid excessive intake 2
• Verify vitamin D status before initiating high-dose therapy 2, 3
• Consider that dietary supplements, including those not labeled as containing vitamin D, may be contaminated with high doses 5

Monitoring During Recovery

• Regular assessment of serum calcium levels until normalization 1
• Periodic monitoring of 25(OH)D levels until return to normal range 4
• Assessment of renal function until complete recovery 3
• Maintenance of low calcium diet may be necessary for months after exposure 5