Magnesium, phosphate and chloride

Question 1

In adults, magnesium deficiencies are seen most frequently in patients with (5)

Answer 1

1 alcoholism, 
2 malnutrition, 
3 cirrhosis, 
4 pancreatitis, 
5 excessive GI fluid losses.

Question 2

Renal wasting of [Mg2+] can be seen with

Answer 2

1 loop diuretics, 
2 hypophosphatemia, 
3 ketoacidosis, 
4 aminoglycosides,  
5 nephrotoxic chemotherapeutic agents.

Question 3

The ECG changes seen with magnesium deficiencies include (4), especially in the precordial leads.

Answer 3

1 prolonged PR and QT intervals,
2 widened QRS complexes,
3 depression of ST segments,
4 inversion of T waves

Question 4

Approximately … of the administered [Mg2+] will be lost in the urine.

Answer 4

half

Question 5

Most likely hypermagnesemia presentation relevant to the ED (3)

Answer 5

1 untreated DKA
2 Rhabdomyolysis
3 Magnesium-containing laxatives, antacids, or enemas

Question 6

Symptoms and Signs of Hypermagnesemia

Answer 6

Level (mEq/L) Symptom

2. 0-3.0 Nausea
3. 0-4.0 Somnolence
4. 0-8.0 Loss of deep tendon reflexes
5. 0-12.0 Respiratory depression
6. 0-15.0 Hypotension, heart block, cardiac arrest

Question 7

The possibility of hypermagnesemia should be considered in patients with … or…

Answer 7

hyperkalemia

hypercalcemia.

Question 8

Hypermagnesemia in normal kidney

Answer 8

1) Dilution with IV fluid
2) Furosemide (40 to 80)
3) 5 ml of CaCl2 over 5 min [direct antagonizing effect]

*** HD in renal failure pt.

Question 9

Hypochloremia is usually caused by (3)

Answer 9

1 excessive diuresis,
2 vomiting, or
3 nasogastric tube drainage