Episodic generalized weakness can occur due to all of the following acute electrolyte disturbances, EXCEPT:

Disturbances in potassium, calcium, magnesium as well as hypophosphatemia can affect the muscle function dramatically. Hypocalcemia is known to cause tetany and not muscle weakness. Hypokalemia or hyperkalemia can cause flaccid paralysis of peripheral neurogenic type. Hypophosphatemia causes peripheral weakness. Early signs of hyponatremia are muscle cramps, weakness, and fatigue, they reflect the effects of hyponatremia on skeletal muscle function. Early signs of hypercalcemia includes drowsiness, lethargy, muscle weakness, headache, constipation and a metallic taste in mouth. ECG changes includes shoened QT interval and hea block. Severe hypercalcemia can cause arrhythmias, cardiac arrest and coma. Ref: Fundamentals of Neurology: An Illustrated Guide By Marco Mumenthaler, page 126. Poable Pathophysiology, page 518.