Hypokalemic periodic paralysis (HPP) is a rare disorder characterized by attacks of muscle weakness due to hypokalemia. Although it is transmitted autosomal dominantly it can also be seen sporadically.

A 37-year-old female patient was admitted to our hospital with complaints of weakness in both arms and legs, and fatigue lasting for 8-24 hours and repeating once in every 10-15 days. The clinical signs of the disease initiated in the first decade and she was followed up with a diagnosis of conversion disorder. She had flask paralysis in four extremities and decrease in deep tendon reflexes during the attacks. Between the attacks serum potassium level was 3.9 mEq/l, however during the attacks it was 3.0 mEq/l. With this clinical status and laboratory findings, we diagnosed the patient with hypokalemic periodic paralysis.

Hypokalemic periodic paralysis which is characterized by attacks, can be misdiagnosed as a conversion disorder, because the patient is neurologically normal. For this reason HPP must be considered in differential diagnosis of similar paroxismal disorders.

Hypokalemia Periodic paralysis Conversion disorder Electromyography