Evaluation and treatment of hypomagnesemia
- Alan S L Yu, MB, BChir
Alan S L Yu, MB, BChir
- Harry Statland and Solon Summerfield Professor of Medicine
- University of Kansas Medical Center
Most of the body's magnesium stores are intracellular, principally within bone. In the extracellular fluid, magnesium can be ionized (free), bound to anions, or bound to protein. (See "Regulation of magnesium balance".)
The plasma magnesium concentration is not usually measured as part of routine blood tests. Thus, the identification of patients with hypomagnesemia often requires clinical suspicion in patients with risk factors for hypomagnesemia (eg, chronic diarrhea, proton pump inhibitor therapy, alcoholism, diuretic use) or with clinical manifestations of hypomagnesemia (eg, unexplained hypocalcemia, refractory hypokalemia, neuromuscular disturbances, ventricular arrhythmias) [1,2]. (See "Causes of hypomagnesemia" and "Clinical manifestations of magnesium depletion".)
This topic will review the evaluation and treatment of hypomagnesemia. The regulation of magnesium balance, and the causes and clinical manifestations of hypomagnesemia are presented in detail elsewhere. (See "Regulation of magnesium balance" and "Causes of hypomagnesemia" and "Clinical manifestations of magnesium depletion".)
In patients diagnosed with hypomagnesemia, the cause can usually be obtained from the history. (See "Causes of hypomagnesemia".)
If no etiology is apparent, the distinction between gastrointestinal and renal losses can be made by measuring the 24-hour urinary magnesium excretion or the fractional excretion of magnesium on a random urine specimen.
- Weisinger JR, Bellorín-Font E. Magnesium and phosphorus. Lancet 1998; 352:391.
- Agus ZS. Hypomagnesemia. J Am Soc Nephrol 1999; 10:1616.
- al-Ghamdi SM, Cameron EC, Sutton RA. Magnesium deficiency: pathophysiologic and clinical overview. Am J Kidney Dis 1994; 24:737.
- Elisaf M, Panteli K, Theodorou J, Siamopoulos KC. Fractional excretion of magnesium in normal subjects and in patients with hypomagnesemia. Magnes Res 1997; 10:315.
- Ryzen E, Nelson TA, Rude RK. Low blood mononuclear cell magnesium content and hypocalcemia in normomagnesemic patients. West J Med 1987; 147:549.
- Hébert P, Mehta N, Wang J, et al. Functional magnesium deficiency in critically ill patients identified using a magnesium-loading test. Crit Care Med 1997; 25:749.
- Ryzen E, Elbaum N, Singer FR, Rude RK. Parenteral magnesium tolerance testing in the evaluation of magnesium deficiency. Magnesium 1985; 4:137.
- Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122:S729.
- Kraft MD, Btaiche IF, Sacks GS, Kudsk KA. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm 2005; 62:1663.
- Gunn VL, Nechyba C. The Harriet Lane Handbook, 16th ed, Mosby, 2002.
- Kleinman ME, Chameides L, Schexnayder SM, et al. Part 14: pediatric advanced life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122:S876.
- Reed BN, Zhang S, Marron JS, Montague D. Comparison of intravenous and oral magnesium replacement in hospitalized patients with cardiovascular disease. Am J Health Syst Pharm 2012; 69:1212.
- Dai LJ, Raymond L, Friedman PA, Quamme GA. Mechanisms of amiloride stimulation of Mg2+ uptake in immortalized mouse distal convoluted tubule cells. Am J Physiol 1997; 272:F249.
- Normomagnesemic magnesium depletion
- Patients with severe symptoms
- - Inefficiency of intravenous magnesium supplementation
- Patients with no or minimal symptoms
- - Oral repletion if available and tolerable
- - Intravenous repletion in stable hospitalized patients
- Correction of the underlying disease
- Treating patients with impaired renal function
- Duration of therapy
- SUMMARY AND RECOMMENDATIONS