Final answer:
Hyponatremia is a condition characterized by a lower-than-normal concentration of sodium in the blood. It can lead to swelling of cells and potentially result in brain damage or death. Hyponatremia can be caused by various factors such as sodium imbalance, water retention, or abnormal loss of sodium.
Step-by-step explanation:
Hyponatremia is a lower-than-normal concentration of sodium in the blood, usually associated with excess water accumulation in the body. This dilutes the sodium and can lead to various complications. At the cellular level, hyponatremia causes increased entry of water into cells, leading to swelling of cells and potentially resulting in brain damage or death. Hyponatremia can be caused by an imbalance of sodium in other fluid compartments of the body, water retention related to edema or congestive heart failure, or abnormal loss of sodium due to conditions such as excessive sweating, vomiting, or diarrhea.