Last updated: November 7, 2022

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Hypomagnesemia (low serum magnesium) is very common in critically unwell patients but can occur in the community, particularly secondary to medication use. Magnesium has a vital role in membrane stabilization and while the symptoms of mild deficiency can be nonspecific, severe hypomagnesemia can cause serious complications, such as cardiac arrhythmias and seizures. Hypomagnesemia is commonly seen alongside other electrolyte abnormalities, and magnesium levels should always be checked in patients with hypokalemia or hypocalcemia. Management consists of magnesium replacement, treatment of associated electrolyte imbalances, and addressing the underlying causes.

  • Serum magnesium concentration < 1.5 mEq/dL [1]
  • Severe hypomagnesemia: magnesium concentration < 1.0 mEq/dL [1]
Causes of hypomagnesemia
Causes [1][2]
Cell shifts

Low body magnesium stores can affect many organ systems. The presence and severity of symptoms do not always correlate with serum magnesium levels. [2]

Parenteral administration of magnesium can reduce serum calcium levels, which can worsen preexisting hypocalcemia.

We list the most important complications. The selection is not exhaustive.

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  1. Martin KJ, González EA, Slatopolsky E. Clinical Consequences and Management of Hypomagnesemia. Journal of the American Society of Nephrology. 2008; 20 (11): p.2291-2295. doi: 10.1681/asn.2007111194 . | Open in Read by QxMD
  2. Hansen B-A, Bruserud Ø. Hypomagnesemia in critically ill patients. Journal of Intensive Care. 2018; 6 (1). doi: 10.1186/s40560-018-0291-y . | Open in Read by QxMD
  3. Nardone R, Brigo F, Trinka E. Acute Symptomatic Seizures Caused by Electrolyte Disturbances. J Clin Neurol. 2016; 12 (1): p.21-33. doi: 10.3988/jcn.2016.12.1.21 . | Open in Read by QxMD
  4. Efstratiadis G, Sarigianni M, Gougourelas I. Hypomagnesemia and cardiovascular system.. Hippokratia. 2006; 10 (4): p.147-52.
  5. Safavi M, Badiei S, Daftari-Fard N, Honarmand A. Different doses of intravenous Magnesium sulfate on cardiovascular changes following the laryngoscopy and tracheal intubation: A double-blind randomized controlled trial. J Res Pharm Pract.. 2015; 4 (2): p.79-84. doi: 10.4103/2279-042x.154365 . | Open in Read by QxMD
  6. Garnier A-S, Duveau A, Planchais M, Subra J-F, Sayegh J, Augusto J-F. Serum Magnesium after Kidney Transplantation: A Systematic Review. Nutrients. 2018; 10 (6): p.729. doi: 10.3390/nu10060729 . | Open in Read by QxMD
  7. Hypomagnesemia. https://www.msdmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypomagnesemia. Updated: March 1, 2018. Accessed: December 6, 2019.
  8. Ahmed F, Mohammed A. Magnesium: The Forgotten Electrolyte—A Review on Hypomagnesemia. Med Sci (Basel). 2019; 7 (4): p.56. doi: 10.3390/medsci7040056 . | Open in Read by QxMD
  9. Deheinzelin D, Negri EM, Tucci MR, et al. Hypomagnesemia in critically ill cancer patients: a prospective study of predictive factors. Braz J Med Biol Res. 2000; 33 (12): p.1443-1448. doi: 10.1590/s0100-879x2000001200007 . | Open in Read by QxMD

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