Magnesium Lecture Notes Review

Flashcards about Magnesium and related conditions.

How are Magnesium, Calcium and phosphate related?

Levels are closely related to Calcium and Phosphate. Direct relationship with Calcium, indirect relationship with Phosphate.

What are 3 common causes of Hypomagnesemia?

Chronic alcoholism (most common), Gastrointestinal Loss, Refeeding Syndrome

How does alcohol cause magnesium loss?

Vomiting, and increased renal excretion of magnesium.

How long does it usually take for magnesium levels to decrease?

2-3 days of admission

Which part of the GI system absorbs the most magnesium?

The distal small bowel. Damage from surgery or diseases (eg crohn’s) will reduce absorption.

How is magnesium lost through the gastrointestinal system?

Nasogastric suction, diarrhea or fistulas

Which area of gastrointestinal fluid has more magnesium the upper or the lower?

Lower has 10-14 mEq/L

What increases magnesium loss?

Malabsorption and steatorrhea (fatty stool)

During Refeeding Syndrome, which ions shift into cells, lowering their levels in the plasma?

Potassium, Magnesium, and Phosphate

What are the most dangerous cardiovascular effects of Hypomagnesemia?

Cardiac arrhythmias and sudden death.

Which treatments are often ineffective in cases of magnesium deficiency?

Standard antiarrhythmic treatments and defibrillation.

What ECG changes may be present in severe hypomagnesemia?

Prolonged PR, prolonged QT, widened QRS, ST segment depression, and T-wave flattening.

What is a significant neurological effect of Hypermagnesemia?

Decrease in neuromuscular transmission, leading to neuromuscular blockage.

What does magnesium inhibiting acetylcholine release do to muscles?

Reduces muscle excitability and slower or absent deep tendon reflexes.

How does magnesium affect neuromuscular junctions?

Magnesium acts as a calcium antagonist, inhibiting acetylcholine release from motor nerve terminals.

What happens as magnesium levels rise, and neuromuscular blockages develop?

Potential muscle paralysis, and respiratory depression

What are the key cardiovascular effects of Hypermagnesemia?

Hypotension due to vasodilation. Arrhythmias - bradycardia, AV block, asystole.

What ECG changes are associated with hypermagnesemia?

prolonged PR, widening of QRS complex, prolonged QT.