For pediatric PN patients, selenium supplementation is typically started after how long on PN?

• A. 2 weeks
• B. 3 weeks
• C. 1 month
• D. 2 months

Answer: (C)

Selenium is a trace element needed for antioxidant defense and immune function, and for thyroid metabolism. In children on parenteral nutrition, stores of selenium can support the body for several weeks, but as PN continues and growth proceeds, the risk of deficiency rises. Therefore, many pediatric PN protocols initiate selenium supplementation after about one month on PN to ensure ongoing adequacy during a growing child’s course of therapy, helping prevent deficiency without extending exposure longer than necessary in the early phase. Starting earlier (a couple of weeks) can be premature for some patients, while delaying beyond a month increases the chance of deficiency during continued PN. A month represents a balanced, commonly used timing for repletion as the PN plan becomes more stable.