Hypermagnesemia

Hypermagnesemia is defined as a serum magnesium concentration exceeding the normal value. It refers to a condition where blood [Mg2+] > 1.05 mmol/L. Apart from a few iatrogenic factors causing excessive magnesium entry into the body, it is mostly due to decreased excretion caused by renal dysfunction. As with hypomagnesemia, serum magnesium concentration is not a reliable indicator of increased magnesium, because 25% of serum magnesium is bound to protein and this portion does not exert physiological effects; magnesium ions are mainly intracellular, so when the body's magnesium content increases, serum magnesium may remain within the normal range. However, in general, the degree of hypermagnesemia is consistent with the degree of increased body magnesium. Just as the kidney's regulation of sodium ions, potassium ions, and bicarbonate ions has a certain delayed effect, the kidney's regulation of magnesium does not rapidly exert an obvious effect either. Therefore, if large amounts of intravenous magnesium preparations are administered without monitoring, severe hypermagnesemia can also occur. If combined with renal dysfunction, the kidney's regulatory role is severely weakened, making hypermagnesemia more likely to occur.