Question
Which of the following are approximate daily requirements of the common electrolytes in an adult?
- Sodium 50–90 mM/day
- Calcium 1 mM/day
- Potassium 50 mM/day
- Magnesium 1 mM/day
| A. |
1, 2, and 3
|
| B. |
1, 2, and 4
|
| C. |
2, 3, and 4
|
| D. |
1, 3, and 4
|
Show Answer
|
Correct Answer » D
Explanation
|
|
Normal Daily Adult Electrolyte Requirements
| Electrolyte |
Approximate Daily Requirement |
| Sodium (Na⁺) |
50–100 mmol/day |
| Potassium (K⁺) |
40–80 mmol/day (≈50 mmol/day) |
| Calcium (Ca²⁺) |
10–20 mmol/day |
| Magnesium (Mg²⁺) |
0.5–1 mmol/kg/day (≈1 mmol/day supplementation requirement often quoted in fluid therapy) |
Evaluation of Statements
1. Sodium: 50–90 mmol/day
This is the approximate daily sodium requirement in adults.
2. Calcium: 1 mmol/day
Incorrect.
Daily calcium requirement is approximately:
- 1000 mg/day
- ≈ 25 mmol/day
Therefore, 1 mmol/day is far too low.
3. Potassium: 50 mmol/day
The usual maintenance requirement is approximately 40–80 mmol/day.
4. Magnesium: 1 mmol/day
Maintenance magnesium requirement is approximately 0.5–1 mmol/kg/day
