Hyperchloremia may result from which condition?

• A. Head trauma
• B. Decreased glomerular filtration
• C. Increased perspiration
• D. Excessive administration of chloride relative to sodium

Answer: (D)

Chloride is the major extracellular anion, and its serum level rises when there is more chloride than the body can balance with sodium and bicarbonate. The most direct way this happens is by giving a large amount of chloride relative to sodium, such as administering chloride-rich IV fluids (for example, normal saline), which increases the extracellular chloride load and can lead to hyperchloremia.

Head trauma on its own doesn’t inherently raise chloride levels. Decreased glomerular filtration can contribute to accumulation of many solutes, including chloride, but the classic and most immediate cause is a disproportionate chloride load from fluids. Increased perspiration tends to lose chloride with sweat rather than raise serum chloride. So the condition that best explains hyperchloremia is excessive administration of chloride relative to sodium.