Periodic Paralysis is a rare disease defined as recurrent episodes of flaccid paralysis which may occur in inherited or in sporadic forms.

According to the plasma K⁺ level during attack, periodic paralysis can be classified as Hypokalemic, Hyperkalemic and Normokalemic type.

Weakness or paralysis are caused by conduction block in neuromuscular junction and along the muscle membrane.

3 cases of Hypokalemic periodic paralysis and 1 case of probable Hyperkalemic periodic paralysis are presented with blood chemistry, urinalysis, EKG, muscle biopsy and with EMG findings during attacks compared with normal status.

Keywords :Periodic paralysis, Electromyography, Hypokalemia, Hyperkalemia