Parenteral magnesium load evaluation of malnourished Thai children

Abstract

Parenteral magnesium load tests were conducted to evaluate the magnesium status of 32 malnourished Northern Thai children. A 56 hour test was elaborated to study electrolyte and creatinine excretion before and after an intramuscular magnesium load of 0.49 mEq. per kilogram. No diurnal excretion pattern for magnesium was found, and the magnesium rejected by the kidney was excreted within 16 hours. A 24 hour test with an 8 hour preload and a 16 hour postload collection period provided the same information as the longer trial, and hence 24 hour tests were conducted. The mean retention on admission was 56.67 per cent, unchanged on Day 7, and 17.15 per cent on Day 70. The magnesium load increased the urinary excretion of calcium and sodium but not that of potassium, creatinine, or water. Low plasma magnesium values usually related to high magnesium retention, but some patients with high retention had normal plasma values. Low magnesium content of urine on admission was not a useful guide to the magnesium status. High magnesium retention was related to severe antecedent gastroenteritis.