1Serum 25(OH)D Interpretation
Vitamin D3 (cholecalciferol) functions as a fundamental pro-hormone in calcium homeostasis, bone mineralization, and neuromuscular stability. In India, despite geographic tropical latitude, widespread Vitamin D deficiency (VDD) persists (estimated between 70% and 90%). Contributing factors include cutaneous melanin pigmentation, dense particulate atmospheric pollution blocking UV-B wavelengths (290–315 nm), and clothing practices limiting direct sunlight exposure.
| Status | ng/mL | nmol/L | Pathophysiological Correlate |
|---|---|---|---|
| Deficiency | < 20 | < 50 | Associated with secondary hyperparathyroidism, osteomalacia, and rickets. |
| Insufficiency | 21 – 29 | 51 – 74 | Subclinical bone resorption; suboptimal calcium absorption efficiency. |
| Sufficiency | 30 – 100 | 75 – 250 | Target optimal range for bone health and parathyroid suppression. |
| Toxicity | > 150 | > 375 | Hypercalcaemia, nephrocalcinosis, polyuria, systemic ectopic calcification. |
2The "60,000 IU" Weekly Protocol
In Indian outpatient medicine, the 60,000 IU weekly dose represents the clinical cornerstone for correcting adult deficiency. Because daily low-dose compliance is traditionally poor, pulse weekly oral dosing with 60,000 IU cholecalciferol capsules or granules for 8 consecutive weeks delivers a cumulative replacement load of 480,000 IU, reliably raising serum levels into the target range (>30 ng/mL).
3Stoss Therapy for Nutritional Rickets
In paediatric cases with florid rachitic skeletal signs (craniotabes, widened wrists, rachitic rosary, bow legs) where medication adherence over 6 to 12 weeks cannot be verified, Stoss therapy provides an effective pulse intervention:
- Infants < 10 kg: 300,000 IU administered as a single oral or intramuscular dose.
- Children ≥ 10 kg: 600,000 IU administered as a single oral or intramuscular dose.
4Calcium Co-Supplementation & "Hungry Bone" Risk
5Hypervitaminosis D (Toxicity)
Vitamin D toxicity occurs almost exclusively via iatrogenic or over-the-counter excessive supplementation, presenting with hypercalcaemia:
- Impaired renal concentration: polyuria, polydipsia, dehydration.
- Gastrointestinal: nausea, intractable constipation, anorexia.
- Central nervous system: confusion, lethargy, psychomotor retardation.
- Renal: nephrolithiasis, nephrocalcinosis, acute kidney injury.