A serum sodium level below 135 mEq/L indicates which condition?

• A. Hypernatremia
• B. Hyponatremia
• C. Hypokalemia
• D. Hyperkalemia

Answer: (B)

A serum sodium level below 135 mEq/L indicates hyponatremia, a condition characterized by low sodium concentrations in the blood. Sodium is a key electrolyte in the body that plays a crucial role in maintaining fluid balance, blood pressure regulation, and proper muscle and nerve function. When sodium levels drop below the normal range, it can lead to various clinical symptoms, including headache, confusion, seizures, and in severe cases, coma.

Hyponatremia can occur due to several factors, such as excessive fluid retention, loss of sodium through vomiting or diuretics, or medical conditions affecting hormone levels. Understanding hyponatremia is vital for managing patients, as treatment often involves correcting the sodium imbalance carefully to prevent complications.