Symptomatic hypomagnesemia in children.

Between January 1996 and June 1998, 24 children with symptomatic hypomagnesemia were enrolled for analysis of their symptomatology, causes, and treatment outcome. Hypocalcemia and hyperphosphatemia suggesting impaired parathyroid function were the most common electrolyte disorders. Hypokalemia was also frequently noted. The related symptoms including seizure, tetany, and weakness were common. Drug-induced renal magnesium wasting was the most common cause of symptomatic hypomagnesemia, and tended to occur in older children using aminoglycoside, furosemide, and amphotericin-B. The associated gastrointestinal causes might add a minor contribution to the development of hypomagnesemia. Analyses of PTH levels in 13 children suggested that inhibition of PTH synthesis or secretion was responsible for hypomagnesemic hypocalcemia in most patients. However, peripheral PTH resistance might also account for the mechanism in a few patients. In most patients, symptomatic hypomagnesemia was transient, and improved after magnesium provision. Only one child with congenital renal magnesium wasting and two with primary hypomagnesemia needed long-term magnesium treatment.