This document discusses hyponatremia, which refers to low sodium levels in the blood. It defines hyponatremia as a change in the ratio of sodium to total body water. Various causes of hyponatremia are described, including thiazide diuretics, liver failure, heart failure, and renal failure. Hypertonic hyponatremia caused by high blood glucose is explained in more detail. Potential treatments discussed include isotonic saline, tolvaptan, demeclocycline, and restricting free water intake. The document cautions that certain treatments like tolvaptan are contraindicated in liver failure due to toxicity risks.