Which statement is true regarding manganese and patients on long‑term parenteral nutrition (PN)?

Which statement is true regarding manganese and patients on long‑term parenteral nutrition (PN)?

• A. Hypermanganesemia has not been reported in any PN patients
• B. The best indicator of manganese status is urinary manganese
• C. Manganese deficiency occurs in PN for greater than 1 year
• D. Manganese in commercial trace element preparations may result in hypermanganesemia

Answer: (D)

Manganese balance in long-term parenteral nutrition is shaped by how the body handles this trace element and how PN supplements contribute to the total load. Manganese is excreted mainly via bile, so when liver function is impaired or bile flow is reduced—as can happen with prolonged PN—the element can accumulate in the body. Commercial trace element preparations provide a fixed manganese amount, and this added load can push Mn levels higher in patients with cholestasis or hepatic dysfunction, leading to hypermanganesemia and potential neurologic effects. Urinary excretion isn’t a reliable reflection of body manganese status because most of the elimination is biliary. Deficiency is not a common risk in long-term PN when Mn is included in trace elements. Therefore, the statement that manganese in commercial trace element preparations may result in hypermanganesemia correctly captures the risk in these patients.

Manganese balance in long-term parenteral nutrition is shaped by how the body handles this trace element and how PN supplements contribute to the total load. Manganese is excreted mainly via bile, so when liver function is impaired or bile flow is reduced—as can happen with prolonged PN—the element can accumulate in the body. Commercial trace element preparations provide a fixed manganese amount, and this added load can push Mn levels higher in patients with cholestasis or hepatic dysfunction, leading to hypermanganesemia and potential neurologic effects. Urinary excretion isn’t a reliable reflection of body manganese status because most of the elimination is biliary. Deficiency is not a common risk in long-term PN when Mn is included in trace elements. Therefore, the statement that manganese in commercial trace element preparations may result in hypermanganesemia correctly captures the risk in these patients.