Low dose Vitamin D and Stoss Regimen

The management of nutritional rickets primarily involves the administration of Vitamin D and calcium. Historically, high-dose "Stoss" therapy was popular, but current guidelines favor daily low-dose regimens due to safety concerns.

1. Daily Low-Dose Vitamin D Therapy (Current Standard of Care)

This approach involves the administration of physiological or slightly pharmacological doses of Vitamin D over a prolonged period to gradually replenish body stores.

Regimen Details

• Dosage: The recommended dosage varies by age:
  • Infants (< 1 year): 2000 IU/day,.
  • Children (> 1 year): 3000–6000 IU/day,,.
• Duration: Therapy is typically continued for 12 weeks (3 months) to ensure complete healing of osteomalacia and replenishment of stores,.
• Maintenance: Following the 12-week intensive phase, the child is transitioned to a daily maintenance dose of 400 IU (infants) to 600 IU (children) to prevent recurrence,.
• Adjuncts: Oral calcium supplementation (30–75 mg/kg/day) is mandatory during the initial phase to prevent hypocalcemia caused by rapid bone remineralization ("hungry bone syndrome"),,.

Advantages

• Safety Profile: This method is significantly safer than high-dose therapy. It minimizes the large spikes in serum Vitamin D levels that can lead to toxicity.
• Reduced Renal Risk: There is a much lower risk of developing hypercalciuria (excess calcium in urine) and nephrocalcinosis (calcium deposition in kidneys) compared to Stoss therapy.
• Physiological Repletion: It allows for a more controlled and steady restoration of bone mineralization and Vitamin D status.
• Efficacy: Current guidelines state that this method is not only safer but also a more effective way to treat rickets compared to single massive doses.

Disadvantages

• Compliance: The primary drawback is the need for strict adherence to daily medication for a long duration (12 weeks).
• Reliability: In settings with poor social support or understanding, parents may forget doses, leading to treatment failure.

2. Stoss Therapy (Mega-Dose Therapy)

"Stoss" is derived from a German word meaning "push." This therapy involves administering a massive dose of Vitamin D to rapidly fill body stores.

Regimen Details

• Dosage: A massive dose of 300,000 to 600,000 IU of Vitamin D is administered,,.
• Administration:
  • It can be given as a single oral or intramuscular dose,.
  • Alternatively, it can be divided into 2–4 doses given over a 24-hour period.
  • If radiological healing is not observed within 2–3 weeks, the dose may sometimes be repeated.
• Mechanism: Vitamin D is fat-soluble and is stored in the adipose tissue and muscle, from where it is slowly released over months.

Advantages

• Guaranteed Compliance: Because the entire course is administered under medical supervision (often as a single observed dose), compliance is ensured.
• Convenience: It avoids the need for daily administration by parents, making it useful in populations where long-term adherence is questionable or follow-up is difficult,.
• Rapid Stores: It rapidly fills the body's Vitamin D pool.

Disadvantages

• Hypercalcemia: The massive influx of Vitamin D can lead to dangerously high serum calcium levels (hypercalcemia),.
• Hypercalciuria and Nephrocalcinosis: High calcium excretion in the urine is a frequent complication, which significantly increases the risk of renal stones and nephrocalcinosis (permanent calcium deposits in the kidney tissue),,.
• Toxicity: There is a narrow therapeutic index with such high doses, increasing the risk of Vitamin D toxicity (Hypervitaminosis D).
• Monitoring Requirements: Due to toxicity risks, closer monitoring of serum calcium and urinary calcium is ideally required, which may not always be feasible in resource-limited settings.

3. Intermediate/Alternative Strategies

To balance the safety of daily dosing with the convenience of Stoss therapy, alternative intermittent regimens have been proposed.

• Weekly/Fortnightly Dosing: In older children where daily compliance is doubtful, higher doses (e.g., 60,000 IU) can be given once weekly or once every two weeks for a total of roughly 300,000–600,000 IU over a few weeks,.
• Therapeutic Trial: A specific trial of Stoss therapy (600,000 IU) is sometimes used diagnostically to differentiate nutritional rickets from refractory rickets (X-linked hypophosphatemia or Vitamin D dependent rickets). If no healing occurs after 4-6 weeks of this massive dose, the rickets is termed "refractory",.

Summary of Differences