Severe hypermagnesemia

Q: 52 years old male with End Stage Renal Disease (ESRD) presented to Emergency Department (ED) with respiratory failure and hypotension. Patient was intubated in the field. In ED patient was found to have a complete heart block. ER physician emergently inserted an intravenous pacemaker which stabilizes the hemodynamics. On clinical exam, the patient is unresponsive and has lost reflexes. Labs showed abnormalities, but the most pronounced was a magnesium level of 17.0 mEq/L. Intravenous calcium is given. What should be the next step?



Answer: Emergent Dialysis

Magnesium has a fairly good therapeutic margin, but hypermagnesemia is a risk in some patients, particularly renal failure. Mild hypermagnesemia may cause weakness, nausea, vomiting, and hypotension, but it can become progressively life-threatening. Following are the ballpark clinical signs/symptoms depending on magnesium level.

• 4.0 mEq/L hyporeflexia
• 5.0 mEq/L Prolonged atrioventricular conduction
• 7.0-10.0 mEq/L - loss of patellar reflex
• 10.0-13.0 mEq/L - respiratory depression and various heart block
• Above 13.0 mEq/L - cardiac arrest/Asystole.

The mainstay of treatment is withdrawing magnesium supplementation, intravenous calcium, diuretics, and in severe cases, dialysis.

#electrolytes

Reference:

Bansal AD, Negoianu D, Warburton KM. An Unusual yet "Mg"nificent Indication for Hemodialysis. Semin Dial. 2016 May;29(3):247-50. doi: 10.1111/sdi.12479. Epub 2016 Feb 25. PMID: 26915350; PMCID: PMC5492508.