Hyponatremia is a metabolic condition marked by a lack of sodium in the body fluids outside the cells. This imbalance of salt to water is typically caused by three conditions: euvolemic hyponatremia, hypervolemic hyponatremia, or hypovolemic hyponatremia. It is the most common electrolyte disorder in the United States, and it has a number of debilitating symptoms.
Read more about hyponatremia symptoms and treatment options in this 2009 article in Clinical Geriatrics: Hyponatremia in the Elderly: Risk Factors, Clinical Consequences, and Management.
You might also like this related case report: Hyponatremia in an Elderly Woman: Making a Beside Diagnosis