Hyponatremia is a medical condition characterized by low levels of sodium in the blood. Sodium is an essential electrolyte that helps regulate water balance in the body, and when its levels drop, it can lead to various health issues. Common causes include excessive fluid intake, certain medications, and underlying health conditions such as heart failure or kidney disease. Symptoms of hyponatremia can range from mild to severe and may include headache, confusion, nausea, and in extreme cases, seizures or coma. Treatment typically involves addressing the underlying cause and may include fluid restriction or sodium replacement, depending on the severity of the condition.