Hypermagnesemia

Background

• High >3.5
• Magnesium is an effective calcium channel blocker both extracellularly and intracellularly
• Intracellular magnesium profoundly blocks several cardiac potassium channels.

Diagnosis

• 2–3 - Nausea
• 3–4 - Somnolence
• 4–8 - Loss of DTRs
• 8–12 - Respiratory depression
• 12–15 - Hypotension, heart block, Cardiac Arrest

DDX

1. Renal Failure
2. Lithium
3. Volume depletion
4. Rhabdo
5. IV Mg (goal in PET/eclampsia 5-7 mEq/L)
6. Massive PO intake (laxative abusers, Epsom salts)
7. Magnesium enemas

Treatment

1. IVF (NS)
2. Furosemide 20-40mg IVP
3. CaCl 10% 5mL IV over 5min
4. HD for Mg > 8 or poor renal function

See Also

• Electrolyte Abnormalities (Main)

Hypomagnesemia

Source

Tintinalli