Hypermagnesemia

  • Etiology
    • Defined as serum magnesium > 2.2 mEq/L
      • Not symptomatic until >4
    • PTH release is impaired in Mg >6mg/dl
    • MCC is Renal Failure
      • Caused by real function impairment (decreased excretion) or supplements
      • Flushing with diminished reflexes to flaccid quadriplegia, apnea, and cardiac arrest, rare finding
    • Iatrogenic
      • Laxatives, IV mg treatment for preeclampsia
      • DKA, tumor lysis syndrome, Excessive tissue breakdown
      • Adrenal insufficiency
      • Rhabdomyolysis
  • Symptoms
    • Hyporeflexia (first sign)
    • Lethargy, Weakness, Paralysis
    • Facial Parethesias
    • Respiratory failure if the diaphragm is affected
    • Bradycardia, Hypotension, Cardiac Arrest
  • Imaging
    • EKG: Prolonged PR, QRS, and QT intervals
    • Complete Heart block or asystole if >15 mEq/dl
  • Labs
    • ± Hypocalcemia
  • Treatment
    • Quit mg containing agents
    • Normal Saline and a loop diuretic
    • Calcium gluconate (Cardioprotective)
    • Mechanical Ventilation
    • Dialysis if renal failure