title: Fractional excretion of magnesium in normal subjects and in patients with hypomagnesemia.
abstract: The aim of our study was the determination of fractional excretion of magnesium (FEMg++) in both normal subjects and hypomagnesemic patients. 142 subjects aged 26-72 years, recruited from our lipid clinic (control population) and 74 hypomagnesemic patients, aged 36-75 years, were studied. The mean FEMg++ in the control population was 1.8 per cent (range, 0.5-4 per cent). FEMg++ was not correlated with either serum magnesium or with serum creatinine. The mean FEMg++ in patients with hypomagnesemia of extrarenal origin was 1.4 per cent (range, 0.5-2.7 per cent), while the mean FEMg++ in hypomagnesemic patients in whom renal magnesium loss was the main etiologic factor for the pathogenesis of hypomagnesemia was 15 per cent (range, 4-48 per cent). In both groups of hypomagnesemic patients FEMg++ was positively correlated with the urinary magnesium to creatinine molar ratio, but was not correlated with serum magnesium or creatinine levels. FEMg++ could better distinguish the two groups of hypomagnesemic patients than the urinary magnesium to creatinine molar ratio. Hypomagnesemic patients exhibited a cluster of other acid-base and electrolyte abnormalities, mainly respiratory alkalosis, hypokalemia, hypophosphatemia, and hypocalcemia. In conclusion, in hypomagnesemic patients with normal renal function FEMg++ is a very useful tool for the diagnostic approach of hypomagnesemia. A value more than 4 per cent is indicative of inappropriate magnesium loss.
authors.affiliation: Department of Internal Medicine, University of Ioannina Medical School, Greece.
authors.forename: M
authors.initials: M
authors.lastname: Elisaf
authors.forename: K
authors.initials: K
authors.lastname: Panteli
authors.forename: J
authors.initials: J
authors.lastname: Theodorou
authors.forename: K C
authors.initials: KC
authors.lastname: Siamopoulos
mesh_terms: D000328:Adult; D000368:Aged; D000471:Alkalosis / Q000150:complications; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000150:complications; D007008:Hypokalemia / Q000150:complications; D017674:Hypophosphatemia / Q000150:complications; D008274:Magnesium / Q000097:blood / Q000652:urine*; D008275:Magnesium Deficiency / Q000150:complications / Q000652:urine*; D008297:Male; D008875:Middle Aged
chemical_list: D003404:Creatinine; D008274:Magnesium