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  • Clinician



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 [2][1]
Cell shifts

Clinical features

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.

  • 1. Martin KJ, González EA, Slatopolsky E. Clinical Consequences and Management of Hypomagnesemia. Journal of the American Society of Nephrology. 2008; 20(11): pp. 2291–2295. doi: 10.1681/asn.2007111194.
  • 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.
  • 3. Nardone R, Brigo F, Trinka E. Acute Symptomatic Seizures Caused by Electrolyte Disturbances. J Clin Neurol. 2016; 12(1): pp. 21–33. doi: 10.3988/jcn.2016.12.1.21.
  • 4. Efstratiadis G, Sarigianni M, Gougourelas I. Hypomagnesemia and cardiovascular system. Hippokratia. 2006; 10(4): pp. 147–52. pmid: 22087052.
  • 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): pp. 79–84. doi: 10.4103/2279-042x.154365.
  • Lewis, J. Hypomagnesemia. https://www.msdmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypomagnesemia. Updated March 1, 2018. Accessed December 6, 2019.
  • Ahmed F, Mohammed A. Magnesium: The Forgotten Electrolyte—A Review on Hypomagnesemia. Med Sci (Basel). 2019; 7(4): p. 56. doi: 10.3390/medsci7040056.
  • 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): pp. 1443–1448. doi: 10.1590/s0100-879x2000001200007.
last updated 09/22/2020
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