## Diagnosis: Nutritional Rickets The clinical presentation—bowing of legs, frontal bossing, delayed fontanelle closure, elevated alkaline phosphatase, and hypocalcemia—is classic for **nutritional rickets due to vitamin D deficiency**, common in children with inadequate sun exposure and poor dietary intake of fortified foods. ## Drug of Choice: Cholecalciferol (Vitamin D3) **Key Point:** Cholecalciferol (Vitamin D3) is the first-line and preferred agent for nutritional rickets because it is: - The most physiologic form of vitamin D (same as endogenous synthesis) - Long-acting with better compliance (weekly or monthly dosing) - Cost-effective and widely available - Converted to active metabolites by the liver and kidney as needed ## Dosing in Nutritional Rickets **High-Yield:** Standard dosing for nutritional rickets: - **Therapeutic dose:** 60,000 IU weekly for 6–12 weeks, OR 600,000 IU as a single IM dose - **Maintenance:** 400–600 IU daily after healing - Calcium supplementation (500 mg elemental calcium daily) is given concurrently ## Why Cholecalciferol Over Alternatives | Agent | Indication | Limitation | |-------|-----------|------------| | **Cholecalciferol (D3)** | Nutritional rickets (1st-line) | Requires hepatic & renal conversion | | Ergocalciferol (D2) | Alternative if D3 unavailable; less potent | Shorter half-life, less stable | | Calcitriol (active 1,25-OH D3) | Hypoparathyroidism, renal rickets | Expensive, risk of hypercalcemia, requires monitoring | | Alfacalcidol (1α-OH D3) | Renal osteodystrophy | Expensive, not first-line for nutritional rickets | **Clinical Pearl:** In nutritional rickets, the kidneys and liver are intact, so the body can efficiently convert cholecalciferol to its active form. Active metabolites (calcitriol, alfacalcidol) are reserved for conditions of impaired conversion (chronic kidney disease, hypoparathyroidism). **Warning:** Do NOT use calcitriol as first-line in nutritional rickets—it is expensive, requires careful monitoring to avoid hypercalcemia, and is unnecessary when the conversion pathway is intact. [cite:IAP Guidelines on Vitamin D Deficiency in Children; Park 26e Ch 10]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.