F+E: Magnesium Imbalances

Magnesium deficit (hypomagnesemia)

Serum magnesium <1.8 mg/dL

Hypomagnesemia Contributing Factors:

Chronic alcoholism, hyperparathyroidism, hyperaldosteronism, diuretic phase of acute kidney injury, malabsorptive disorders, diabetic ketoacidosis, refeeding after starvation, parenteral nutrition, chronic laxative use, diarrhea, acute myocardial infarction, heart failure, decreased serum K+ and Ca++ and certain pharmacologic agents (e.g., gentamicin, cisplatin, cyclosporine)

Hypomagnesemia Signs and Symptoms:

Neuromuscular irritability, positive Trousseau sign and Chvostek sign, insomnia, mood changes, anorexia, vomiting, increased tendon reflexes, and ↑ BP.

ECG: PVCs, flat or inverted T waves, depressed ST segment, prolonged PR interval, and widened QRS, Torsade’s De Point

Hypomagnesemia Signs and Symptoms: Think Everything HIGH!

High HR

High BP

High RR

Hyperactive state: irritability, seizures, twitches, confusion, Trousseau’s + Chvostek’s

What is an important route of magnesium loss, and in what situations can it occur?

The GI tract; losses can occur with nasogastric suction, diarrhea, or fistulas.

Hypomagnesemia Interventions:

• Magnesium sulfate IV.

• Monitor cardiac rhythm.

Magnesium excess (hypermagnesemia)

Serum magnesium >2.6 mg/dL

Hypermagnesemia Contributing Factors:

Oliguric phase of acute kidney injury (particularly when magnesium-containing medications are given), adrenal insufficiency, excessive IV magnesium administration, diabetic ketoacidosis, and hypothyroidism, magnesium containing antiacids and laxatives.

Hypermagnesemia Signs and Symptoms:

Flushing, hypotension, muscle weakness, drowsiness, hypoactive reflexes, depressed respirations, cardiac arrest and coma, diaphoresis.

ECG: tachycardia → bradycardia, prolonged PR interval and QRS, peaked T waves

Hypermagnesemia Signs and Symptoms: Think Everything LOW!

Low energy: drowsiness/coma

Low HR

Low BP

Low RR

Low DTR (hyporeflexia)

Low bowel activity (sounds)

Hypermagnesemia Interventions:

• IV calcium gluconate.

• Diuretics or dialysis.

Magnesium Rich foods:

Choclate, Avocado, Bananas, Pumpkin, Cauliflower, Carrots, Meats, Nuts, Seafood, Whole-grain breads and cereals