Magnesium deficiency in critical illness.

Area of Science:

• Critical Care Medicine
• Biochemistry
• Clinical Pathology

Background:

• Magnesium (Mg) deficiency is prevalent in critically ill patients, associated with increased mortality and adverse clinical outcomes in the intensive care unit (ICU).
• Mg plays a role in conditions such as hypokalemia, hypocalcemia, tetany, dysrhythmia, acute coronary syndromes, acute cerebral ischemia, and asthma.
• Mg regulates numerous enzyme systems, including those controlling intracellular calcium, thereby influencing smooth muscle vasoconstriction, a key factor in critical illness pathophysiology.

Purpose of the Study:

• To review the role of magnesium in critical illness.
• To discuss the challenges in diagnosing magnesium deficiency.
• To evaluate the evidence for magnesium therapy in various critical care scenarios.

Main Methods:

• Literature review of studies concerning magnesium's role in critical illness.
• Analysis of diagnostic limitations for magnesium deficiency, including serum Mg levels.
• Examination of clinical trial data supporting magnesium therapy for specific conditions.

Main Results:

• Serum Mg levels have limitations in assessing Mg status, making diagnosis difficult.
• Alternative assessments like magnesium tolerance testing and ionized Mg2+ have challenges in the ICU setting.
• Magnesium therapy is supported for symptomatic hypomagnesemia, preeclampsia, and torsade de pointes; its use in acute myocardial infarction is not supported.

Conclusions:

• Magnesium deficiency is a significant concern in critical illness with diagnostic challenges.
• Further evaluation is needed for magnesium therapy in severe asthma exacerbations, post-coronary bypass grafting dysrhythmias, and as a neuroprotective agent.
• Understanding magnesium's complex role is crucial for optimizing patient care in the ICU.