eMedicine: Hyponatremia: Sandy Craig, MD explains how the body controls sodium levels, causes, lab work, treatment, and follow-up care.eMedicine: Hyponatremia: Clinical article disusses this electrolyte abnormality is often a complication of other medical illnesses. Includes definition, physical and neurological symptoms, causes, diet, and medication.Hyponatremia: Brief article discusses causes, signs and symptoms, and treatment.Hyponatremia: Details include definition, description, causes and symptoms, diagnosis, treatment, prognosis, and key terms.MedlinePlus: Hyponatremia: Illustrated article offers alternative names, incidence and risk factors, signs and tests, treatment, and prognosis.