Selenium administration to a ten-year-old patient receiving long-term total parenteral nutrition (TPN)--changes in selenium concentration in the blood and hair.

Muscle pain in the lower limbs occurred in a child with short bowel syndrome who has been receiving longterm total parenteral nutrition (TPN). Biochemical parameters revealed that the plasma and erythrocyte selenium concentrations were below the normal range for children and intravenous injection of selenium prepared from selenious acid was started at a dose of 100 micrograms per day. Muscle pain in the lower limbs disappeared one month afterwards. At this point in time, the elevation of the plasma selenium concentration was noted but the erythrocyte selenium concentration remained low. When administration was suspended due to catheter-induced fever five months later, the whole blood selenium concentration decreased again and the symptoms recurred. Accordingly, the dose of selenium was increased to 200 micrograms/day. Subsequently, the blood selenium concentration recovered to the normal range for children. After the dose increase to 200 micrograms/day, concentrations in hair samples collected at every centimeter distance from the root end were determined. The selenium concentration at the root end was found to be higher than the normal range for children, indicating that this was an excessive dose case. Although the dose was decreased from 200 micrograms/day to 120 micrograms/day, the plasma and erythrocyte selenium levels did not go down. Furthermore, the selenium level in the hair reached a plateau, and no recurrence of symptoms was observed. The above results indicate the usefulness of monitoring the selenium concentration in hair in addition to determining the blood selenium level and GSH-Px activity in administering selenium to children undergoing TPN.