Your child has been diagnosed and treated for hyponatremia. This is a low level of sodium in the blood. Sodium helps the body work normally. Too little sodium can cause health problems. Very low sodium can cause death. A low level of sodium has many causes. In small babies, it's commonly caused by formula that is watered down. Or it's caused by giving too much plain water to drink. In older children, it can be caused by drinking excessive amounts of water, some medicines, dehydration, or severe burns. Kidney, heart, and liver conditions can also cause it. Preventing hyponatremia includes getting treatment for the condition that caused low sodium levels. Below is what you need to know about home care. Your child's doctor may give you other instructions.