I myself am looking to see if there is indeed such a condition. Well, what I mean is that generally it is called hypokalemia. Hypo, meaning not enough, is exactly what this is talking about. Hypopotassium, if you ever indeed write it that way, is having too little or not enough potassium in the body where as hyper would be having too much. It is an important electrolyte in the body, and too much or too little can be a bad thing. However, it is generally called hypokalemia.