Hyponatremia is defined as which of the following?

Hyponatremia is defined as which of the following?

• A. Blood sodium less than 136 mEq/L; excess of water to salt.
• B. Blood sodium over 145 mEq/L.
• C. Blood potassium over 5.1 mEq/L.
• D. Blood pH below 7.35.

Answer: (A)

Hyponatremia means there is not enough sodium in the blood, defined by a serum sodium level below about 136 mEq/L. This usually reflects an excess of water relative to salt, diluting the sodium concentration rather than a large loss of sodium on its own. So the description of a blood sodium below 136 mEq/L with an excess of water to salt fits hyponatremia best. In contrast, a high sodium level indicates hypernatremia, a high potassium level indicates hyperkalemia, and a low pH indicates acidosis rather than hyponatremia.

Hyponatremia means there is not enough sodium in the blood, defined by a serum sodium level below about 136 mEq/L. This usually reflects an excess of water relative to salt, diluting the sodium concentration rather than a large loss of sodium on its own. So the description of a blood sodium below 136 mEq/L with an excess of water to salt fits hyponatremia best. In contrast, a high sodium level indicates hypernatremia, a high potassium level indicates hyperkalemia, and a low pH indicates acidosis rather than hyponatremia.