Hypomagnesemia

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Presentation :

• Neuromuscular irritability
• Commonly associated with hypocalcemia, and hypokalemia.

Pathophysiology :

• Most common causes include:
  • GI losses (diarrhea, steatorrhea, intestinal bypass, pancreatitis)
  • Renal losses (loop and thiazide diuretics, alcohol induced)
  • Medications (cisplatin, aminoglycosides, amphotericin B, cyclosporine)
  • Hungry bone syndrome following parathyroidectomy
• Hypomagnesemia is often associated with hypokalemia because of urine potassium wasting.
• Hypomagnesemia is also associated with hypocalcemia because of lower PTH secretion and end-organ resistance to PTH.

Diagnostic Testing:

• Commonly associated with hypocalcemia, and hypokalemia.
• GI and kidney losses can be differentiated by measuring the 24-hour urine magnesium excretion (elevated in kidney losses, low in GI losses).

Treatment :

• Min goal Mg > 1 mg/dL
  • Oral slow-release magnesium (mild to moderate)
  • IV magnesium sulfate (severe)
• Correction of associated hypokalemia and hypocalcemia AFTER Mg correction

Prognosis:

References: