Muscle Weakness, Spasms, Cramps and Tetany
In order for muscle cells to contract, a marked difference in intracellular and extracellular potassium concentrations must exist. As potassium levels drop, this concentration difference decreases and the muscles are unable to function normally. This causes generalized fatigue and a variety of muscular symptoms including weakness, spasms, twitching and cramps. In cases of extreme hypokalemia, the muscles can go into a sustained involuntary state of contraction called tetany.
Read more:
http://www.livestrong.com/article/92806-symptoms-potassium-deficiency/#ixzz2T2yMlaRD