In the sodium level table, which condition is associated with high sodium?

• A. Acute diarrhea
• B. Chronic diarrhea
• C. Burns
• D. Severe burns

Answer: (B)

High sodium shows up when there is a loss of free water without a matching loss of sodium, leading to a concentrating of sodium in the blood. In chronic diarrhea, there is a persistent, ongoing loss of large volumes of watery stool. If a person cannot replace the lost water adequately, their total body water declines more than their sodium loss, causing the plasma sodium concentration to rise. That’s why, in a sodium level table, chronic diarrhea is associated with higher sodium levels.

Think of it as the body running low on water relative to potassium and sodium; the remaining fluid becomes more concentrated, so the sodium reading goes up.