Definition: Magnesium (Mg) > 2.4 mEq/L (3 mg/dL)

Classification/Severity

• Mild: > 2.4 mEq/L (3 mg/dL)
• Moderate: > 4 mEq/L (5 mg/dL)
• Severe: > 10 mEq/L (12 mg/dL)

Causes

• Overdose in Renal Failure Patients on Laxatives or Antacids (PPI)
• Massive Oral Ingestion
• Magnesium Enemas

Presentation

• Mild Hypermagnesemia:
  • Mostly Asymptomatic
• Moderate Hypermagnesemia:
  • Hyporeflexia/Diminished Deep Tendon Reflexes (DTR)
  • Bradycardia
  • Headache
  • Lethargy
  • Nausea and Vomiting
• Severe Hypermagnesemia:
  • Muscle Paralysis
  • Third Degree AV Block (Complete Heart Block)
  • Respiratory Failure
  • Coma and Death

Treatment

• Primary Treatment: Normal Saline and Furosemide (Lasix)
• First Step: Give IV Calcium
  • To Antagonize the Cardiovascular and Neuromuscular Effects of Hypermagnesemia
• Severe Cases May Require Dialysis
• Patients with Normal Renal Function Generally Require No Treatment, Just Cessation of Magnesium Therapy