What can occur as a result of water moving into the cells due to SIADH?

In cases of Syndrome of Inappropriate Antidiuretic Hormone (SIADH), the excess release of antidiuretic hormone (ADH) leads to increased water retention in the body. This condition causes water to move into the cells, resulting in a dilution of sodium levels in the extracellular fluid. As the water accumulates inside the cells, the concentration of sodium in the bloodstream decreases, leading to hyponatremia.

Hyponatremia is characterized by a serum sodium level that is lower than normal, typically defined as less than 135 mmol/L. The dilution of sodium occurs as a direct consequence of water retention, reflecting the imbalance created by the excess ADH. This condition can have several neurological effects, including confusion, seizures, and altered mental status, depending on the severity of the hyponatremia.

The other conditions listed do not result from the water retention associated with SIADH. Dehydration typically would lead to elevated sodium levels (hypernatremia), while hypercalcemia and hypernatremia are not direct consequences of the water shifts seen with SIADH. Therefore, recognizing hyponatremia as the correct outcome of water moving into cells due to SIADH is fundamental for