Magnesium disorder

Question 1

Normal values of Magnesium

Answer 1

-1.5 - 2 mEq/L
-intracellular

Question 2

What are the important functions of Magnesium?

Answer 2

-important cellular protein synthesis cofactor

-controls potassium excretion: Hypomagnesemia leads to increased potassium excretion

-low Magnesium and low potassium often seen together

Question 3

Causes of Hypomagnesemia

Answer 3

-below 1.5 mEq/L

-Causes
Decreased intestinal absorption (cant absorb Mg effectively)
Alcohol abuse (malnourishment/ vomiting)
Medications: Amphotericin (antifungal), cisplatin, aminoglycoside, diuretics

Question 4

Symptoms and Signs of Hypomagnesemia

Answer 4

-CV: heart palpation/ arrhythmias

-Neuro: tetany (involuntary muscle contraction, overstimulated peripheral nerves), twitching, convulsion

-low K, low Ca

Question 5

IV Treatment of Hypomagnesemia

Answer 5

-IV magnesium (preferred)
if mild (1-1.5 mEq/L): give 1-2g IV once
if severe (<1 or symptoms): give 3-4g IV once

Rate:
normally: 1-2g per hour
life-threatening: 2g Mg sulfate in D5W pushed over 2-15 minutes

Question 6

PO Treatment of Hypomagnesemia

Answer 6

Outpatient
400 mg of Magnesium Oxide PO q8h
ADR: diarrhea

Question 7

How long does it take to replete Magnesium stores?

Answer 7

3-5 days especially with oral drugs

Question 8

Causes of Hypermagnesemia

Answer 8

-more than 2.4 mEq/L
-CKD
-Magnesium consumption: antacids, laxatives (abuse)

Question 9

Signs and symptoms of Hypermagnesemia

Answer 9

-CV: arrhythmias
-(if severe) Neuro: loss of deep tendon reflexes, lethargy, confusion

Question 10

Treatment of Hypermagnesemia

Answer 10

-Diuretics and normal saline - to dilute the Mg and eliminate it through the kidneys

-IV calcium: not to treat the hypermagnesemia but to stabilize the myocardium and to prevent arrhythmias from occurring

-in severe cases: Hemodialysis
(A E I O U; electrolyte (Magnesium) is one of the indicators of hemodialysis use)