Hyponatremia is defined as:

Hyponatremia is defined as:

• A. High sodium content of blood
• B. Normal sodium content
• C. Elevated sodium in tissues
• D. Low sodium content of blood and tissues

Answer: (D)

Hyponatremia means there is too little sodium in the circulating fluid. The defining measure is a low serum (blood) sodium concentration, which reflects a reduced extracellular sodium amount and can cause water to shift into cells. The option that describes low sodium content of blood and tissues best aligns with this systemic low-sodium state (clinical focus is on serum sodium, typically below 135 mEq/L). The other choices describe high sodium, normal sodium, or elevated sodium in tissues, which do not define hyponatremia.

Hyponatremia means there is too little sodium in the circulating fluid. The defining measure is a low serum (blood) sodium concentration, which reflects a reduced extracellular sodium amount and can cause water to shift into cells. The option that describes low sodium content of blood and tissues best aligns with this systemic low-sodium state (clinical focus is on serum sodium, typically below 135 mEq/L). The other choices describe high sodium, normal sodium, or elevated sodium in tissues, which do not define hyponatremia.